SlideShare a Scribd company logo

Declare Your Language: Virtual Machines & Code Generation

Eelco Visser, profile picture
Eelco Visser

The document summarizes virtual machines and code generation. It discusses how high-level programming languages are abstracted from low-level machine details through virtual machines. The Java Virtual Machine architecture and bytecode instructions are described, including its stack-based design, threads, heap, and method area. Code generation mechanics like string operations are also covered.

Software
1 of 133
Download to read offline
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
Eelco Visser IN4303 Compiler Construction TU Delft November 2017 Declare Your Language Chapter 10: Virtual Machines & Code Generation
Virtual Machines & Code Generation 2 backend frontend parse desugar analyse normalise generate optimise format
Linguistic Abstraction - High-level programming languages abstract from low-level machine mechanics - Abstractions in imperative and object-oriented languages - Calling Conventions - Register machines vs stack machines Java Virtual Machine - Architecture - Operation stack - Constant pool - Local variables - Heap - Stack frames - Class ïŹles Code Generation Mechanics - Printing strings - String concatenation - String interpolation - Transformation Outline 3
Reading Material 4
5
Java Virtual Machine Tim Lindholm, Frank Yellin: The Java Virtual Machine SpeciïŹcation, 2nd edition. Addison-Wesley, 1999. Bill Venners: Inside the Java 2 Virtual Machine. McGraw-Hill, 2000. Activation Records Andrew W. Appel, Jens Palsberg: Modern Compiler Implementation in Java, 2nd edition. 2002 Literature: VMs & Compilation 6
Imperative Languages - Carl A. Gunter: Semantics of Programming Languages: Structures and Techniques. MIT Press, 1992 - Kenneth C. Louden: Programming Languages: Principles and Practice. Course Technology, 2002 Object-Oriented Languages - Martin Abadi, Luca Cardelli: A Theory of Objects. Springer, 1996. - Kim B. Bruce: Foundations of Object-Oriented Programming Languages: Types and Semantics. MIT Press, 2002. - Timothy Budd: An Introduction to Object-Oriented Programming. Addison- Wesley, 2002. Literature: Semantics of Programming Languages 7
State & Control 8
Machine state - a pile of data stored in memory - memory hierarchy: registers, RAM, disk, network, 
 Imperative program - computation is series of changes to memory - basic operations on memory (increment register) - controlling such operations (jump, return address, 
) - control represented by state (program counter, stack, 
) State 9
General purpose registers - accumulator AX - arithmetic operations - counter CX - shift/rotate instructions, loops - data DX - arithmetic operations, I/O - base BX - pointer to data - stack pointer SP, base pointer BP - top and base of stack - source SI, destination DI - stream operations Special purpose registers - segments SS, CS, DS, ES, FS, GS - ïŹ‚ags EFLAGS Registers: x86 Family 10
Example: x86 Assembler 11 mov AX [1] mov CX AX L: dec CX mul CX cmp CX 1 ja L mov [2] AX read memory write memory calculation jump
Example: Java Bytecode 12 .method static public m(I)I iload 1 ifne else iconst_1 ireturn else: iload 1 dup iconst_1 isub invokestatic Math/m(I)I imul ireturn read memory calculation jump
Memory abstractions - variables: abstract over data storage - expressions: combine data into new data - assignment: abstract over storage operations Control-ïŹ‚ow abstractions - structured control-ïŹ‚ow: abstract over unstructured jumps - ‘go to statement considered harmful’ Edgser Dijkstra, 1968 Memory & Control Abstractions 13
Example: C 14 int f = 1 int x = 5 int s = f + x while (x > 1) { f = x * f ; x = x - 1 } variable expression assignment control flow
Example: Tiger 15 /* factorial function */ let var f := 1 var x := 5 var s := f + x in while x > 1 do ( f := x * f ; x := x - 1 ) end variable expression assignment control flow
Procedures 16
Control-ïŹ‚ow abstraction - Procedure: named unit of computation - Procedure call: jump to unit of computation and return Memory abstraction - Formal parameter: the name of the parameter - Actual parameter: value that is passed to procedure - Local variable: temporary memory Recursion - Procedure may (indirectly) call itself - Consequence? Procedural Abstraction 17
Example: Procedures in C 18 #include <stio.h> /* factorial function */ int fac( int num ) { if (num < 1) return 1; else return num * fac(num - 1) ; } int main() { int x = 10 ; int f = fac( x ) ; int x printf(“%d! = %dn”, x, f); return 0; } formal parameter actual parameter local variable recursive call
Procedures in Tiger 19 /* factorial function */ let function fac( n: int ) : int = let var f := 1 in if n < 1 then f := 1 else f := (n * fac(n - 1) ); f end var f := 0 var x := 5 in f := fac( x ) end formal parameter actual parameter local variable recursive call
Stack - temporary storage - grows from high to low memory addresses - starts at SS Stack frames - return address - local variables - parameters - stack base: BP - stack top: SP Implementing Procedures with Stack and Stack Frames 20
General purpose registers - accumulator AX - arithmetic operations - counter CX - shift/rotate instructions, loops - data DX - arithmetic operations, I/O - base BX - pointer to data - stack pointer SP, base pointer BP - top and base of stack - source SI, destination DI - stream operations Special purpose registers - segments SS, CS, DS, ES, FS, GS - ïŹ‚ags EFLAGS Reminder: Registers in x86 Family 21
Example: Procedures in x86 Assembler 22 push 21 push 42 call _f add SP 8 push BP mov BP SP mov AX [BP + 8] mov DX [BP + 12] add AX DX pop BP ret pass parameter access parameter new stack frame old stack frame free parameters
Caller - push parameters right-to-left on the stack - clean-up stack after call Callee - save old BP - initialise new BP - save registers - return result in AX - restore registers - restore BP Calling Conventions: CDECL 23 push 21 push 42 call _f add ESP 8 push EBP mov EBP ESP mov EAX [EBP + 8] mov EDX [EBP + 12] add EAX EDX pop EBP ret
caller - push parameters right-to-left on the stack callee - save old BP - initialise new BP - save registers - return result in AX - restore registers - restore BP Calling Conventions: STDECL 24 push 21 push 42 call _f@8 push EBP mov EBP ESP mov EAX [EBP + 8] mov EDX [EBP + 12] add EAX EDX pop EBP ret 8
Caller - passes parameters in registers - pushes additional parameters right-to-left ‹ on the stack Callee - save old BP, initialise new BP - save registers - return result in AX - restore registers - restore BP - cleans up the stack Calling Conventions: FASTCALL 25 mov ECX 21 mov EDX 42 call @f@8 push EBP mov EBP ESP mov EAX ECX add EAX EDX pop EBP ret
Procedure declarations - in principle: full freedom - project constraints - target platform constraints Procedure calls - need to match procedure declarations Precompiled libraries - avoid recompilation - source code not always available Standardization - compilers / high-level languages standardize use of calling conventions - portable code: does not depend on particular calling convention Calling Conventions 26
Object-Oriented Languages (home work) 27
Objects - generalisation of records - identity - state - behaviour Messages - objects send and receive messages - trigger behaviour - imperative realisation: method calls Modularity: Objects & Messages 28
Classes - generalisation of record types - characteristics of objects: attributes, ïŹelds, properties - behaviour of objects: methods, operations, features Encapsulation - interface exposure - hide attributes & methods - hide implementation Modularity: Classes 29 public class C { public int f1; private int f2; public void m1() { return; } private C m2(C c) { return c; } }
Inheritance - inherit attributes & methods - additional attributes & methods - override behaviour - nominative subtyping Interfaces - avoid multiple inheritance - interface: contract for attributes & methods - class: provide attributes & methods - nominative subtyping Inheritance vs Interfaces 30 public class C { public int f1; public void m1() {
} public void m2() {
} } public class D extends C { public int f2; public void m2() {
} public void m3() {
} } public interface I { public int f; public void m(); } public class E implements I { public int f; public void m() {
} public void m’() {
} }
Ad-hoc polymorphism - overloading ‣ same method name, independent classes ‣ same method name, same class, diïŹ€erent parameter types - overriding ‣ same method name, subclass, compatible types Universal polymorphism - subtype polymorphism ‣ inheritance, interfaces - parametric polymorphism Polymorphism 31
Dispatch - link method call to method Static dispatch - type information at compile-time Dynamic dispatch - type information at run-time - single dispatch: one parameter - multiple dispatch: more parameters Static vs. Dynamic Dispatch 32
Single Dispatch in Java 33 public class A {} public class B extends A {} public class C extends B {} public class D { public A m(A a) { System.out.println("D.m(A a)"); return a; } public A m(B b) { System.out.println("D.m(B b)"); return b; } } public class E extends D { public A m(A a) { System.out.println("E.m(A a)"); return a; } public B m(B b) { System.out.println("E.m(B b)"); return b; } } A a = new A(); B b = new B(); C c = new C(); D d = new D(); E e = new E(); A ab = b; A ac = c; D de = e; d. m(a); d. m(b); d. m(ab); d. m(c); d. m(ac); e. m(a); e. m(b); e. m(ab); e. m(c); e. m(ac); de.m(a); de.m(b); de.m(ab); de.m(c); de.m(ac);
Methods - parameter types - return type Covariance - method in subclass - return type: subtype of original return type Contravariance - method in subclass - parameter types: supertypes of original parameter types Overriding 34
Overloading vs Overriding 35 public class F { public A m(B b) { System.out.println("F.m(B b)"); return b; } } public class G extends F { public A m(A a) { System.out.println("G.m(A a)"); return a; } } public class H extends F { public B m(B b) { System.out.println("H.m(B b)"); return b; } } A a = new A(); B b = new B(); F f = new F(); G g = new G(); H h = new H(); A ab = b; f.m(b); g.m(a); g.m(b); g.m(ab); h.m(a); h.m(b); h.m(ab);
Invariance 36 public class X { public A a; public A getA() { return a ; } public void setA(A a) { this.a = a ; } } public class Y extends X { public B a; public B getA() { return a ; } public void setA(B a) { this.a = a ; } } A a = new A(); B b = new B(); X y = new Y(); y.getA(); y.setA(b); y.setA(a); String[] s = new String[3] ; Object[] o = s ; o[1] = new A();
Summary: Abstractions 37
Imperative languages - subroutines, routines, procedures, functions, methods - scoping: local variables - declarations with parameters (formal parameters) - calls with arguments (actual parameters) - pass by value, pass by reference Machine code - jumps: call and return - call stack: return address, parameters, private data - procedure prologue and epilogue Abstractions for Memory and Control 38
Imperative languages - state & statements - abstraction over machine code - control ïŹ‚ow & procedures - types Object-oriented languages - objects & messages - classes - inheritance - types Imperative vs Object-Oriented 39
Java Virtual Machine: Architecture 40
JVM Architecture 41
JVM Architecture: Threads 42
JVM Architecture: Thread 43
JVM Architecture: Stack 44
JVM Architecture: Heap 45
JVM Architecture: Method Area 46
JVM Architecture: JVM Stack 47
48 Reverse Engineering the JVM Instruction Set
JVM: Control Flow 49
Bytecode Instructions: Goto 50 pc: 00 method area 00 01 02 03 04 05 06 A7 00 04 00 A7 FF FF goto 04 nop goto 03
Bytecode Instructions: Goto 51 pc: 04 method area 00 01 02 03 04 05 06 A7 00 04 00 A7 FF FF goto 04 nop goto 03
Bytecode Instructions: Goto 52 pc: 03 method area 00 01 02 03 04 05 06 A7 00 04 00 A7 FF FF goto 04 nop goto 03
Bytecode Instructions: Goto 53 pc: 04 method area 00 01 02 03 04 05 06 A7 00 04 00 A7 FF FF goto 04 nop goto 03
JVM: Operand Stack 54
Operand Stack 55 pc: 00 00 01 02 03 04 05 06 pc: 00 optop: 00 00 01 02 03 04 05 06 04 05 10 2A 11 43 03 iconst_1 iconst_2 bipush sipush method area stack
Operand Stack 56 optop: 01pc: 01 00 01 02 03 04 05 06 0000 000100 01 02 03 04 05 06 04 05 10 2A 11 43 03 iconst_1 iconst_2 bipush sipush method area stack
Operand Stack 57 optop: 02pc: 02 00 01 02 03 04 05 06 0000 0001 0000 0002 00 01 02 03 04 05 06 04 05 10 2A 11 43 03 iconst_1 iconst_2 bipush sipush method area stack
Operand Stack 58 optop: 03pc: 04 00 01 02 03 04 05 06 0000 0001 0000 0002 0000 002A 00 01 02 03 04 05 06 04 05 10 2A 11 43 03 iconst_1 iconst_2 bipush sipush method area stack
Operand Stack 59 optop: 04pc: 07 00 01 02 03 04 05 06 0000 0001 0000 0002 0000 002A 0000 4303 00 01 02 03 04 05 06 04 05 10 2A 11 43 03 iconst_1 iconst_2 bipush sipush method area stack
Operand Stack 60 optop: 04 00 01 02 03 04 05 06 0000 0001 0000 0002 0000 002A 0000 4303 pc: 07 07 08 09 0A 0B 0C 0D 60 68 5F 64 9A FF F5 iadd imul swap isub ifne 00 method area stack
Operand Stack 61 optop: 03 00 01 02 03 04 05 06 0000 0001 0000 0002 0000 432D pc: 08 07 08 09 0A 0B 0C 0D 60 68 5F 64 9A FF F5 iadd imul swap isub ifne 00 method area stack
Operand Stack 62 optop: 02 00 01 02 03 04 05 06 0000 0001 0000 865A pc: 09 07 08 09 0A 0B 0C 0D 60 68 5F 64 9A FF F5 iadd imul swap isub ifne 00 method area stack
Operand Stack 63 optop: 02 00 01 02 03 04 05 06 0000 865A 0000 0001 pc: 0A 07 08 09 0A 0B 0C 0D 60 68 5F 64 9A FF F5 iadd imul swap isub ifne 00 method area stack
Operand Stack 64 optop: 01 00 01 02 03 04 05 06 0000 8659 pc: 0B 07 08 09 0A 0B 0C 0D 60 68 5F 64 9A FF F5 iadd imul swap isub ifne 00 method area stack
Operand Stack 65 00 01 02 03 04 05 06 pc: 00 optop: 00 00 01 02 03 04 05 06 04 05 10 2A 11 43 03 iconst_1 iconst_2 bipush sipush method area stack
JVM: Constant Pool 66
Constant Pool 67 pc: 00 method area stack 00 01 02 03 04 05 06 12 00 12 01 14 00 02 ldc 00 ldc 01 ldc2_w 02 00 01 02 03 04 05 06 constant pool 00 01 02 03 04 05 06 0000 002A 0000 4303 0000 0000 0000 002A optop: 00
Constant Pool 68 pc: 02 method area stack 00 01 02 03 04 05 06 12 00 12 01 14 00 02 ldc 00 ldc 01 ldc2_w 02 00 01 02 03 04 05 06 0000 002A constant pool 00 01 02 03 04 05 06 0000 002A 0000 4303 0000 0000 0000 002A optop: 01
Constant Pool 69 pc: 04 method area stack 00 01 02 03 04 05 06 12 00 12 01 14 00 02 ldc 00 ldc 01 ldc2_w 02 00 01 02 03 04 05 06 0000 002A 0000 4303 constant pool 00 01 02 03 04 05 06 0000 002A 0000 4303 0000 0000 0000 002A optop: 02
Constant Pool 70 pc: 07 method area stack 00 01 02 03 04 05 06 12 00 12 01 14 00 02 ldc 00 ldc 01 ldc2_w 02 00 01 02 03 04 05 06 0000 002A 0000 4303 0000 0000 0000 002A constant pool 00 01 02 03 04 05 06 0000 002A 0000 4303 0000 0000 0000 002A optop: 04
JVM: Local Variables 71
Local Variables 72 pc: 00 method area stack 00 01 02 03 04 05 06 04 3B 1A 3C 84 01 01 iconst_1 istore_0 iload_0 istore_1 iinc 01 01 00 01 02 03 04 05 06 local variables 00 01 02 03 04 05 06 optop: 00
Local Variables 73 pc: 01 00 01 02 03 04 05 06 0000 0001 method area stack 00 01 02 03 04 05 06 04 3B 1A 3C 84 01 01 iconst_1 istore_0 iload_0 istore_1 iinc 01 01 local variables 00 01 02 03 04 05 06 optop: 01
Local Variables 74 pc: 02 00 01 02 03 04 05 06 method area stack 00 01 02 03 04 05 06 04 3B 1A 3C 84 01 01 iconst_1 istore_0 iload_0 istore_1 iinc 01 01 local variables 00 01 02 03 04 05 06 0000 0001 optop: 00
Local Variables 75 pc: 03 00 01 02 03 04 05 06 0000 0001 method area stack 00 01 02 03 04 05 06 04 3B 1A 3C 84 01 01 iconst_1 istore_0 iload_0 istore_1 iinc 01 01 local variables 00 01 02 03 04 05 06 0000 0001 optop: 01
Local Variables 76 pc: 04 00 01 02 03 04 05 06 method area stack 00 01 02 03 04 05 06 04 3B 1A 3C 84 01 01 iconst_1 istore_0 iload_0 istore_1 iinc 01 01 local variables 00 01 02 03 04 05 06 0000 0001 0000 0001 optop: 00
Local Variables 77 pc: 07 00 01 02 03 04 05 06 method area stack 00 01 02 03 04 05 06 04 3B 1A 3C 84 01 01 iconst_1 istore_0 iload_0 istore_1 iinc 01 01 local variables 00 01 02 03 04 05 06 0000 0001 0000 0002 optop: 00
JVM: Heap 78
Heap 79 pc: 00 method area stack heap 4303 4303 "Compilers" 002A 002A [20,01,40,02,42] 00 01 02 03 04 05 06 12 00 19 00 12 01 2E ldc 00 aload 00 ldc 01 iaload 00 01 02 03 04 05 06 constant pool 00 01 02 03 04 05 06 4303 4303 0000 0004 local variables 00 01 02 03 04 05 06 002A 002A optop: 00
Heap 80 pc: 02 method area stack heap 4303 4303 "Compilers" 002A 002A [20,01,40,02,42] 00 01 02 03 04 05 06 12 00 19 00 12 01 2E ldc 00 aload 00 ldc 01 iaload 00 01 02 03 04 05 06 4303 4303 constant pool 00 01 02 03 04 05 06 4303 4303 0000 0004 local variables 00 01 02 03 04 05 06 002A 002A optop: 01
Heap 81 pc: 04 method area stack heap 4303 4303 "Compilers" 002A 002A [20,01,40,02,42] 00 01 02 03 04 05 06 12 00 19 00 12 01 2E ldc 00 aload 00 ldc 01 iaload 00 01 02 03 04 05 06 4303 4303 002A 002A constant pool 00 01 02 03 04 05 06 4303 4303 0000 0004 local variables 00 01 02 03 04 05 06 002A 002A optop: 02
Heap 82 pc: 06 method area stack heap 4303 4303 "Compilers" 002A 002A [20,01,40,02,42] 00 01 02 03 04 05 06 12 00 19 00 12 01 2E ldc 00 aload 00 ldc 01 iaload 00 01 02 03 04 05 06 4303 4303 002A 002A 0000 0004 constant pool 00 01 02 03 04 05 06 4303 4303 0000 0004 local variables 00 01 02 03 04 05 06 002A 002A optop: 03
Heap 83 pc: 07 method area stack heap 4303 4303 "Compilers" 002A 002A [20,01,40,02,42] 00 01 02 03 04 05 06 12 00 19 00 12 01 2E ldc 00 aload 00 ldc 01 iaload 00 01 02 03 04 05 06 4303 4303 0000 0042 constant pool 00 01 02 03 04 05 06 4303 4303 0000 0004 local variables 00 01 02 03 04 05 06 002A 002A optop: 02
JVM: Stack Frames 84
Dispatch - link method call to method Static dispatch - type information at compile-time Dynamic dispatch - type information at run-time - single dispatch: one parameter - multiple dispatch: more parameters Static vs. Dynamic Dispatch 85
Example: Static Call 86 .class public Exp .method public static fac(I)I iload 1 ifne else iconst_1 ireturn else: iload 1 dup iconst_1 isub invokestatic Exp/fac(I)I imul ireturn .end method function fac(n: int): int= if n = 0 then 1 else n * fac(n - 1)
Example: Dynamic Call 87 .class public Exp .method public fac(I)I iload 1 ifne else iconst_1 ireturn else: iload 0 iload 1 dup iconst_1 isub invokevirtual Exp/fac(I)I imul ireturn .end method function fac(n: int): int= if n = 0 then 1 else n * fac(n - 1)
Caller - push object - push parameters left-to-right - call method Virtual machine on call - allocate space (frame data, operand stack, local variables) - store frame data (data pointer, return address, exception table) - store parameters as local variables - dynamic dispatch - point pc to method code Code Pattern: Dynamic Method Call 88
Callee - parameters in local variables - leave result on operand stack - return to caller Virtual machine on return - push result on caller’s operand stack - point pc to return address - destroy frame Code Pattern: Return from Method Call 89
Implementation: Heap-Based 90 3 frame data 3 2 fac(3) 2 frame data fac(2) 1 frame data fac(1) 22 21 11 1
Implementation: Stack-Based 91 3 frame data 3 2 fac(3) 2 frame data fac(2) 22 2 1 111 frame data fac(1) 11
Stack Frames 92 00 01 02 03 04 05 06 2A 10 40 B6 00 01 AC aload_0 bipush invokevirtual 01 ireturn optop: 02 method area stack heap 00 01 02 03 04 05 06 4303 4303 0000 0040 local variables 00 01 02 03 04 05 06 4303 4303 pc: 03
Stack Frames 93 pc: 80 80 81 82 83 84 85 86 2B 59 68 AC 00 00 00 iload_1 dup imul ireturn optop: 01 method area stack heap 00 01 02 03 04 05 06 4303 4303 0000 0040 local variables 00 01 02 03 04 05 06 4303 4303 local variables 00 01 02 03 04 05 06 4303 4303 0000 0040 optop: 00 stack 00 01 02 03 04 05 06
Stack Frames 94 pc: 81 80 81 82 83 84 85 86 2B 59 68 AC 00 00 00 iload_1 dup imul ireturn optop: 01 method area stack heap 00 01 02 03 04 05 06 4303 4303 0000 0040 local variables 00 01 02 03 04 05 06 4303 4303 local variables 00 01 02 03 04 05 06 4303 4303 0000 0040 optop: 01 stack 00 01 02 03 04 05 06 0000 0040
Stack Frames 95 pc: 81 80 81 82 83 84 85 86 2B 59 68 AC 00 00 00 iload_1 dup imul ireturn optop: 01 method area stack heap 00 01 02 03 04 05 06 4303 4303 0000 0040 local variables 00 01 02 03 04 05 06 4303 4303 local variables 00 01 02 03 04 05 06 4303 4303 0000 0040 optop: 02 stack 00 01 02 03 04 05 06 0000 0040 0000 0040
Stack Frames 96 pc: 82 80 81 82 83 84 85 86 2B 59 68 AC 00 00 00 iload_1 dup imul ireturn optop: 01 method area stack heap 00 01 02 03 04 05 06 4303 4303 0000 0040 local variables 00 01 02 03 04 05 06 4303 4303 local variables 00 01 02 03 04 05 06 4303 4303 0000 0040 optop: 01 stack 00 01 02 03 04 05 06 0000 1000
Stack Frames 97 00 01 02 03 04 05 06 2A 10 40 B6 00 01 AC aload_0 bipush invokevirtual 01 ireturn optop: 01 method area stack heap 00 01 02 03 04 05 06 0000 1000 local variables 00 01 02 03 04 05 06 4303 4303 pc: 06
JVM: Class Files 98
Java Compiler 99 > ls Course.java > javac -verbose Course.java [parsing started Course.java] [parsing completed 8ms] [loading java/lang/Object.class(java/lang:Object.class)] [checking university.Course] [wrote Course.class] [total 411ms] > ls Course.class Course.java
Class Files: Format 100 magic number CAFEBABE class file version (minor, major) constant pool count + constant pool access flags this class super class interfaces count + interfaces fields count + fields methods count + methods attribute count + attributes
Jasmin Intermediate Language 101 .class public Exp .method public static fac(I)I iload 1 ifne else iconst_1 ireturn else: iload 1 dup iconst_1 isub invokestatic Exp/fac(I)I imul ireturn .end method
Optimization 102
Reasons - code overhead - execution overhead Inlining - replace calls by body of the procedure - source code level Tail recursion - replace recursive calls by loops or jumps - source or machine code level Optimizations 103
Code Generation 104 function fac0(n0: int): int= if n0 = 0 then 1 else n0 * fac0(n0 - 1) .method public static fac0(I)I iload 1 ldc 0 if_icmpeq label0 ldc 0 goto label1 label0: ldc 1 label1: ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
Optimization 105 .method public static fac0(I)I iload_1 ifne else0 iconst_1 ireturn else0: iload_1 dup iconst_1 isub invokestatic Exp/fac0(I)I imul ireturn .end method .method public static fac0(I)I iload 1 ldc 0 if_icmpeq label0 ldc 0 goto label1 label0: ldc 1 label1: ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
Optimization 106 .method public static fac0(I)I iload 1 ifeq label0 ldc 0 goto label1 label0: ldc 1 label1: ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method .method public static fac0(I)I iload 1 ldc 0 if_icmpeq label0 ldc 0 goto label1 label0: ldc 1 label1: ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
Optimization 107 .method public static fac0(I)I iload 1 ifeq label0 ldc 0 ifeq else0 label0: ldc 1 label1: ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method .method public static fac0(I)I iload 1 ifeq label0 ldc 0 goto label1 label0: ldc 1 label1: ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
Optimization 108 .method public static fac0(I)I iload 1 ifeq label0 goto else0 label0: ldc 1 label1: ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method .method public static fac0(I)I iload 1 ifeq label0 ldc 0 ifeq else0 label0: ldc 1 label1: ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
Optimization 109 .method public static fac0(I)I iload 1 ifeq label0 goto else0 label0: ldc 1 ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method .method public static fac0(I)I iload 1 ifeq label0 goto else0 label0: ldc 1 label1: ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
Optimization 110 .method public static fac0(I)I iload 1 ifeq label0 goto else0 label0: ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method .method public static fac0(I)I iload 1 ifeq label0 goto else0 label0: ldc 1 ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
Optimization 111 .method public static fac0(I)I iload 1 ifneq else0 label0: ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method .method public static fac0(I)I iload 1 ifeq label0 goto else0 label0: ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
Optimization 112 .method public static fac0(I)I iload 1 ifneq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method .method public static fac0(I)I iload 1 ifneq else0 label0: ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
Optimization 113 .method public static fac0(I)I iload 1 ifneq else0 ldc 1 ireturn else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method .method public static fac0(I)I iload 1 ifneq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
Optimization 114 .method public static fac0(I)I iload 1 ifneq else0 ldc 1 ireturn else0: iload 1 dup ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method .method public static fac0(I)I iload 1 ifneq else0 ldc 1 ireturn else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
Optimization 115 .method public static fac0(I)I iload_1 ifneq else0 ldc 1 ireturn else0: iload_1 dup ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method .method public static fac0(I)I iload 1 ifneq else0 ldc 1 ireturn else0: iload 1 dup ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
Optimization 116 .method public static fac0(I)I iload_1 ifneq else0 iconst_1 ireturn else0: iload_1 dup iconst_1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method .method public static fac0(I)I iload_1 ifneq else0 ldc 1 ireturn else0: iload_1 dup ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
Tail Recursion Elimination 117
Example: Tail Recursion 118 .class public Exp .method public static fac(I)I iload 1 ifne else iconst_1 ireturn else: iload 1 dup iconst_1 isub invokestatic Exp/fac(I)I imul ireturn .end method
Example: Tail Recursion 119 .class public Exp .method public static fac(I)I iload 1 ifne else iconst_1 ireturn else: iload 1 dup iconst_1 isub invokestatic Exp/fac(I)I imul ireturn .end method .class public Exp .method public static fac(II)I iload 1 ifne else iload 2 ireturn else: iload 1 iconst_1 isub iload 1 iload 2 imul invokestatic Exp/fac(II)I ireturn .end method
Example: Tail Recursion 120 .class public Exp .method public static fac(II)I iload 1 ifne else iload 2 ireturn else: iload 1 iconst_1 isub iload 1 iload 2 imul invokestatic Exp/fac(II)I ireturn .end method .class public Exp .method public static fac(II)I strt: iload 1 ifne else iload 2 ireturn else: iload 1 iconst_1 isub iload 1 iload 2 imul istore 2 istore 1 goto strt
Code Generation: Strings 121
Printing Strings 122 to-jbc = ?Nil() ; <printstring> "aconst_nulln" to-jbc = ?NoVal() ; <printstring> "nopn" to-jbc = ?Seq(es) ; <list-loop(to-jbc)> es to-jbc = ?Int(i); <printstring> "ldc "; <printstring> i; <printstring> "n" to-jbc = ?Bop(op, e1, e2) ; <to-jbc> e1 ; <to-jbc> e2 ; <to-jbc> op to-jbc = ?PLUS() ; <printstring> "iaddn" to-jbc = ?MINUS() ; <printstring> "isubn" to-jbc = ?MUL() ; <printstring> "imuln" to-jbc = ?DIV() ; <printstring> "idivn"
String Concatenation 123 to-jbc: Nil() -> "aconst_nulln" to-jbc: NoVal() -> "nopn" to-jbc: Seq(es) -> <concat-strings> <map(to-jbc)> es to-jbc: Int(i) -> <concat-strings> ["ldc ", i, "n"] to-jbc: Bop(op, e1, e2) -> <concat-strings> [ <to-jbc> e1, <to-jbc> e2, <to-jbc> op ] to-jbc: PLUS() -> "iaddn" to-jbc: MINUS() -> "isubn" to-jbc: MUL() -> "imuln" to-jbc: DIV() -> "idivn"
String Interpolation 124 to-jbc: Nil() -> $[aconst_null] to-jbc: NoVal() -> $[nop] to-jbc: Seq(es) -> <map-to-jbc> es map-to-jbc: [] -> $[] map-to-jbc: [h|t] -> $[[<to-jbc> h] [<map-to-jbc> t]] to-jbc: Int(i) -> $[ldc [i]]
 to-jbc: Bop(op, e1, e2) -> $[[<to-jbc> e1] [<to-jbc> e2] [<to-jbc> op]] to-jbc: PLUS() -> $[iadd] to-jbc: MINUS() -> $[isub] to-jbc: MUL() -> $[imul] to-jbc: DIV() -> $[idiv]
Code Generation: Transformation 125
Compilation by Transformation 126 backend frontend parse desugar analyse normalise generate optimise format
Transformation 127 to-jbc: Nil() -> [ ACONST_NULL() ] to-jbc: NoVal() -> [ NOP() ] to-jbc: Seq(es) -> <mapconcat(to-jbc)> es to-jbc: Int(i) -> [ LDC(Int(i)) ] to-jbc: String(s) -> [ LDC(String(s)) ] to-jbc: Bop(op, e1, e2) -> <mapconcat(to-jbc)> [ e1, e2, op ] to-jbc: PLUS() -> [ IADD() ] to-jbc: MINUS() -> [ ISUB() ] to-jbc: MUL() -> [ IMUL() ] to-jbc: DIV() -> [ IDIV() ] to-jbc: Assign(lhs, e) -> <concat> [ <to-jbc> e, <lhs-to-jbc> lhs ] to-jbc: Var(x) -> [ ILOAD(x) ] where <type-of> Var(x) => INT() to-jbc: Var(x) -> [ ALOAD(x) ] where <type-of> Var(x) => STRING() lhs-to-jbc: Var(x) -> [ ISTORE(x) ] where <type-of> Var(x) => INT() lhs-to-jbc: Var(x) -> [ ASTORE(x) ] where <type-of> Var(x) => STRING()
Transformation 128 to-jbc: IfThenElse(e1, e2, e3) -> <concat> [ <to-jbc> e1 , [ IFEQ(LabelRef(else)) ] , <to-jbc> e2 , [ GOTO(LabelRef(end)), Label(else) ] , <to-jbc> e3 , [ Label(end) ] ] where <newname> "else" => else where <newname> "end" => end to-jbc: While(e1, e2) -> <concat>[ [ GOTO(LabelRef(check)), Label(body) ] , <to-jbc> e2 , [ Label(check) ] , <to-jbc> e1 , [ IFNE(LabelRef(body)) ] ] where <newname> "test" => check where <newname> "body" => body
Transformation: Example 129 function fac(n: int): int= if n = 0 then 1 else n * fac(n - 1) .method public static fac(I)I iload 1 ldc 0 if_icmpeq label0 ldc 0 goto label1 label0: ldc 1 label1: ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac(I)I imul end0: ireturn .end method
Compiler Infrastructure: LLVM backendsfrontends 130 Fortran C Ada PowerPC X86 ARM intermediate representation optimise
Next 131
Back-End - Lecture 11: DataïŹ‚ow Analysis (Nov 28) - Lecture 12: Garbage Collection (Dec 5) - Lecture 13: Just-in-Time Compilation (Interpreters & Partial Evaluation) (Dec 12) Parsing - Lecture 14: LL Parsing (Dec 19) - Lecture 15: LR Parsing (Jan 9) Lab - Lab 6: Testing Type Analysis (Nov 22) - Lab 7: Type Analyis (Dec 6) - Lab 8: Compiling Minimal Programs (Dec 13) - Lab 9: Compiling Expressions and Statements (Dec 22) - Lab 10: Compiling Fields, Parameters, and Variables (Jan 19) Next 132
133

More Related Content

PDF
Compiler Construction | Lecture 11 | Monotone Frameworks
Eelco Visser
 
PDF
Apache Hadoop Java API
Adam Kawa
 
PDF
Run time
Royalzig Luxury Furniture
 
PDF
Alp 05
gswapnil86
 
PDF
Monad presentation scala as a category
samthemonad
 
PDF
Compiler unit 4
BBDITM LUCKNOW
 
PDF
Matlab ch1 intro
Ragu Nathan
 
PPT
Ch9b
kinnarshah8888
 
Compiler Construction | Lecture 11 | Monotone Frameworks
Eelco Visser
 
Apache Hadoop Java API
Adam Kawa
 
Run time
Royalzig Luxury Furniture
 
Alp 05
gswapnil86
 
Monad presentation scala as a category
samthemonad
 
Compiler unit 4
BBDITM LUCKNOW
 
Matlab ch1 intro
Ragu Nathan
 
Ch9b
kinnarshah8888
 

What's hot (20)

PPT
Ch9a
kinnarshah8888
 
PPT
Python (1)
abduldestiny
 
PPTX
C Assignment Help
Programming Homework Help
 
PDF
Survey onhpcs languages
Saliya Ekanayake
 
PPTX
Programming Assignment Help
Programming Homework Help
 
PDF
GNU octave
gauravmalav
 
PPT
10 8086 instruction set
Shivam Singhal
 
PPTX
C++ theory
Shyam Khant
 
PPT
OOP
Syed Zaid Irshad
 
PPTX
Sequential pattern mining
kiran said
 
PPT
Csc1100 lecture14 ch16_pt2
IIUM
 
PPTX
Register allocation and assignment
Karthi Keyan
 
PPTX
Dynamic memory allocation
Burhanuddin Kapadia
 
PDF
Assembly language part I
Mohammed A. Imran
 
PDF
instruction set of 8086
muneer.k
 
PPT
r,rstats,r language,r packages
Ajay Ohri
 
PPT
C++ Overview
kelleyc3
 
PDF
Run time storage
Rasineni Madhan Mohan Naidu
 
DOCX
Yacc topic beyond syllabus
removed_e9743bdb23f1bbf66b54ab0615c39683
 
PDF
Programming with matlab session 1
Infinity Tech Solutions
 
Ch9a
kinnarshah8888
 
Python (1)
abduldestiny
 
C Assignment Help
Programming Homework Help
 
Survey onhpcs languages
Saliya Ekanayake
 
Programming Assignment Help
Programming Homework Help
 
GNU octave
gauravmalav
 
10 8086 instruction set
Shivam Singhal
 
C++ theory
Shyam Khant
 
OOP
Syed Zaid Irshad
 
Sequential pattern mining
kiran said
 
Csc1100 lecture14 ch16_pt2
IIUM
 
Register allocation and assignment
Karthi Keyan
 
Dynamic memory allocation
Burhanuddin Kapadia
 
Assembly language part I
Mohammed A. Imran
 
instruction set of 8086
muneer.k
 
r,rstats,r language,r packages
Ajay Ohri
 
C++ Overview
kelleyc3
 
Run time storage
Rasineni Madhan Mohan Naidu
 
Yacc topic beyond syllabus
removed_e9743bdb23f1bbf66b54ab0615c39683
 
Programming with matlab session 1
Infinity Tech Solutions
 
Ad

Similar to Declare Your Language: Virtual Machines & Code Generation (20)

PDF
Compiler Construction | Lecture 12 | Virtual Machines
Eelco Visser
 
PPT
C language
spatidar0
 
PPT
C language
VAIRA MUTHU
 
PDF
Programming languages
Eelco Visser
 
PPT
sonam Kumari python.ppt
ssuserd64918
 
PPTX
Advanced procedures in assembly language Full chapter ppt
Muhammad Sikandar Mustafa
 
PDF
Introduction - Imperative and Object-Oriented Languages
Guido Wachsmuth
 
PPTX
Introduction to c
amol_chavan
 
PPT
Sedna XML Database: Executor Internals
Ivan Shcheklein
 
PPT
python.ppt
Arun471829
 
PPS
Clanguage
Vidyacenter
 
PPT
python.ppt
ramamoorthi24
 
PDF
Dr archana dhawan bajaj - csharp fundamentals slides
Dr-archana-dhawan-bajaj
 
PPT
other-architectures.ppt
Jaya Chavan
 
PDF
Bozorgmeh os lab
FS Karimi
 
PDF
7986-lect 7.pdf
RiazAhmad521284
 
PPTX
RHCSA EX200 - Summary
Nugroho Gito
 
PPT
Al2ed chapter17
Abdullelah Al-Fahad
 
PDF
DML Syntax and Invocation process
Arvind Surve
 
PDF
S1 DML Syntax and Invocation
Arvind Surve
 
Compiler Construction | Lecture 12 | Virtual Machines
Eelco Visser
 
C language
spatidar0
 
C language
VAIRA MUTHU
 
Programming languages
Eelco Visser
 
sonam Kumari python.ppt
ssuserd64918
 
Advanced procedures in assembly language Full chapter ppt
Muhammad Sikandar Mustafa
 
Introduction - Imperative and Object-Oriented Languages
Guido Wachsmuth
 
Introduction to c
amol_chavan
 
Sedna XML Database: Executor Internals
Ivan Shcheklein
 
python.ppt
Arun471829
 
Clanguage
Vidyacenter
 
python.ppt
ramamoorthi24
 
Dr archana dhawan bajaj - csharp fundamentals slides
Dr-archana-dhawan-bajaj
 
other-architectures.ppt
Jaya Chavan
 
Bozorgmeh os lab
FS Karimi
 
7986-lect 7.pdf
RiazAhmad521284
 
RHCSA EX200 - Summary
Nugroho Gito
 
Al2ed chapter17
Abdullelah Al-Fahad
 
DML Syntax and Invocation process
Arvind Surve
 
S1 DML Syntax and Invocation
Arvind Surve
 
Ad

More from Eelco Visser (20)

PDF
CS4200 2019 | Lecture 5 | Transformation by Term Rewriting
Eelco Visser
 
PDF
CS4200 2019 | Lecture 4 | Syntactic Services
Eelco Visser
 
PDF
CS4200 2019 | Lecture 3 | Parsing
Eelco Visser
 
PDF
CS4200 2019 | Lecture 2 | syntax-definition
Eelco Visser
 
PDF
CS4200 2019 Lecture 1: Introduction
Eelco Visser
 
PDF
A Direct Semantics of Declarative Disambiguation Rules
Eelco Visser
 
PDF
Declarative Type System Specification with Statix
Eelco Visser
 
PDF
Compiler Construction | Lecture 17 | Beyond Compiler Construction
Eelco Visser
 
PDF
Domain Specific Languages for Parallel Graph AnalytiX (PGX)
Eelco Visser
 
PDF
Compiler Construction | Lecture 15 | Memory Management
Eelco Visser
 
PDF
Compiler Construction | Lecture 14 | Interpreters
Eelco Visser
 
PDF
Compiler Construction | Lecture 13 | Code Generation
Eelco Visser
 
PDF
Compiler Construction | Lecture 10 | Data-Flow Analysis
Eelco Visser
 
PDF
Compiler Construction | Lecture 9 | Constraint Resolution
Eelco Visser
 
PDF
Compiler Construction | Lecture 8 | Type Constraints
Eelco Visser
 
PDF
Compiler Construction | Lecture 7 | Type Checking
Eelco Visser
 
PDF
Compiler Construction | Lecture 6 | Introduction to Static Analysis
Eelco Visser
 
PDF
Compiler Construction | Lecture 5 | Transformation by Term Rewriting
Eelco Visser
 
PDF
Compiler Construction | Lecture 4 | Parsing
Eelco Visser
 
PDF
Compiler Construction | Lecture 3 | Syntactic Editor Services
Eelco Visser
 
CS4200 2019 | Lecture 5 | Transformation by Term Rewriting
Eelco Visser
 
CS4200 2019 | Lecture 4 | Syntactic Services
Eelco Visser
 
CS4200 2019 | Lecture 3 | Parsing
Eelco Visser
 
CS4200 2019 | Lecture 2 | syntax-definition
Eelco Visser
 
CS4200 2019 Lecture 1: Introduction
Eelco Visser
 
A Direct Semantics of Declarative Disambiguation Rules
Eelco Visser
 
Declarative Type System Specification with Statix
Eelco Visser
 
Compiler Construction | Lecture 17 | Beyond Compiler Construction
Eelco Visser
 
Domain Specific Languages for Parallel Graph AnalytiX (PGX)
Eelco Visser
 
Compiler Construction | Lecture 15 | Memory Management
Eelco Visser
 
Compiler Construction | Lecture 14 | Interpreters
Eelco Visser
 
Compiler Construction | Lecture 13 | Code Generation
Eelco Visser
 
Compiler Construction | Lecture 10 | Data-Flow Analysis
Eelco Visser
 
Compiler Construction | Lecture 9 | Constraint Resolution
Eelco Visser
 
Compiler Construction | Lecture 8 | Type Constraints
Eelco Visser
 
Compiler Construction | Lecture 7 | Type Checking
Eelco Visser
 
Compiler Construction | Lecture 6 | Introduction to Static Analysis
Eelco Visser
 
Compiler Construction | Lecture 5 | Transformation by Term Rewriting
Eelco Visser
 
Compiler Construction | Lecture 4 | Parsing
Eelco Visser
 
Compiler Construction | Lecture 3 | Syntactic Editor Services
Eelco Visser
 

Recently uploaded (20)

PPTX
Introduction to Artificial Intelligence
lohedi9363
 
PDF
Wondershare Filmora 15 Crack With Activation Key [2025
ghrom2211g
 
PDF
T3DD25 TYPO3 Content Blocks - Deep Dive by André Kraus
Andre Kraus
 
PPTX
Agentic AI Use Case- Contract Lifecycle Management (CLM).pptx
mhxyzzp
 
PDF
How Creative Agencies Leverage Project Management Software.pdf
Orangescrum
 
PDF
How to Choose the Right IT Partner for Your Business in Malaysia
Asian Business Services & Technologies
 
PPTX
Agentic AI : A Practical Guide. Undersating, Implementing and Scaling Autono...
IT IDOL Technologies
 
PPTX
Transform Your Business with a Software ERP System
Canada Software Company
 
PDF
Softaken Excel to vCard Converter Software.pdf
markwillsonmw004
 
PDF
EN-Survey-Report-SAP-LeanIX-EA-Insights-2025.pdf
deepakkhaitan3
 
PDF
Internet Downloader Manager (IDM) Crack 6.42 Build 42 Updates Latest 2025
itskinga12
 
PDF
wealthsignaloriginal-com-DS-text-... (1).pdf
skmiani786
 
PDF
Which alternative to Crystal Reports is best for small or large businesses.pdf
Varsha Nayak
 
PDF
Audit Checklist Design Aligning with ISO, IATF, and Industry Standards — Omne...
rohnjim07
 
PDF
Understanding Forklifts - TECH EHS Solution
TECH EHS Solution
 
PDF
2025 Textile ERP Trends: SAP, Odoo & Oracle
Aetos Technologies
 
PDF
How to Migrate SBCGlobal Email to Yahoo Easily
raymondjones7273
 
PDF
Digital Strategies for Manufacturing Companies
Virendra Rai, PMP
 
PDF
medical staffing services at VALiNTRY
Tiyan Grayson
 
PDF
Internet Downloader Manager (IDM) Crack 6.42 Build 41
ghrom2211g
 
Introduction to Artificial Intelligence
lohedi9363
 
Wondershare Filmora 15 Crack With Activation Key [2025
ghrom2211g
 
T3DD25 TYPO3 Content Blocks - Deep Dive by André Kraus
Andre Kraus
 
Agentic AI Use Case- Contract Lifecycle Management (CLM).pptx
mhxyzzp
 
How Creative Agencies Leverage Project Management Software.pdf
Orangescrum
 
How to Choose the Right IT Partner for Your Business in Malaysia
Asian Business Services & Technologies
 
Agentic AI : A Practical Guide. Undersating, Implementing and Scaling Autono...
IT IDOL Technologies
 
Transform Your Business with a Software ERP System
Canada Software Company
 
Softaken Excel to vCard Converter Software.pdf
markwillsonmw004
 
EN-Survey-Report-SAP-LeanIX-EA-Insights-2025.pdf
deepakkhaitan3
 
Internet Downloader Manager (IDM) Crack 6.42 Build 42 Updates Latest 2025
itskinga12
 
wealthsignaloriginal-com-DS-text-... (1).pdf
skmiani786
 
Which alternative to Crystal Reports is best for small or large businesses.pdf
Varsha Nayak
 
Audit Checklist Design Aligning with ISO, IATF, and Industry Standards — Omne...
rohnjim07
 
Understanding Forklifts - TECH EHS Solution
TECH EHS Solution
 
2025 Textile ERP Trends: SAP, Odoo & Oracle
Aetos Technologies
 
How to Migrate SBCGlobal Email to Yahoo Easily
raymondjones7273
 
Digital Strategies for Manufacturing Companies
Virendra Rai, PMP
 
medical staffing services at VALiNTRY
Tiyan Grayson
 
Internet Downloader Manager (IDM) Crack 6.42 Build 41
ghrom2211g
 

Declare Your Language: Virtual Machines & Code Generation

  • 1. Eelco Visser IN4303 Compiler Construction TU Delft November 2017 Declare Your Language Chapter 10: Virtual Machines & Code Generation
  • 2. Virtual Machines & Code Generation 2 backend frontend parse desugar analyse normalise generate optimise format
  • 3. Linguistic Abstraction - High-level programming languages abstract from low-level machine mechanics - Abstractions in imperative and object-oriented languages - Calling Conventions - Register machines vs stack machines Java Virtual Machine - Architecture - Operation stack - Constant pool - Local variables - Heap - Stack frames - Class ïŹles Code Generation Mechanics - Printing strings - String concatenation - String interpolation - Transformation Outline 3
  • 5. 5
  • 6. Java Virtual Machine Tim Lindholm, Frank Yellin: The Java Virtual Machine SpeciïŹcation, 2nd edition. Addison-Wesley, 1999. Bill Venners: Inside the Java 2 Virtual Machine. McGraw-Hill, 2000. Activation Records Andrew W. Appel, Jens Palsberg: Modern Compiler Implementation in Java, 2nd edition. 2002 Literature: VMs & Compilation 6
  • 7. Imperative Languages - Carl A. Gunter: Semantics of Programming Languages: Structures and Techniques. MIT Press, 1992 - Kenneth C. Louden: Programming Languages: Principles and Practice. Course Technology, 2002 Object-Oriented Languages - Martin Abadi, Luca Cardelli: A Theory of Objects. Springer, 1996. - Kim B. Bruce: Foundations of Object-Oriented Programming Languages: Types and Semantics. MIT Press, 2002. - Timothy Budd: An Introduction to Object-Oriented Programming. Addison- Wesley, 2002. Literature: Semantics of Programming Languages 7
  • 9. Machine state - a pile of data stored in memory - memory hierarchy: registers, RAM, disk, network, 
 Imperative program - computation is series of changes to memory - basic operations on memory (increment register) - controlling such operations (jump, return address, 
) - control represented by state (program counter, stack, 
) State 9
  • 10. General purpose registers - accumulator AX - arithmetic operations - counter CX - shift/rotate instructions, loops - data DX - arithmetic operations, I/O - base BX - pointer to data - stack pointer SP, base pointer BP - top and base of stack - source SI, destination DI - stream operations Special purpose registers - segments SS, CS, DS, ES, FS, GS - ïŹ‚ags EFLAGS Registers: x86 Family 10
  • 11. Example: x86 Assembler 11 mov AX [1] mov CX AX L: dec CX mul CX cmp CX 1 ja L mov [2] AX read memory write memory calculation jump
  • 12. Example: Java Bytecode 12 .method static public m(I)I iload 1 ifne else iconst_1 ireturn else: iload 1 dup iconst_1 isub invokestatic Math/m(I)I imul ireturn read memory calculation jump
  • 13. Memory abstractions - variables: abstract over data storage - expressions: combine data into new data - assignment: abstract over storage operations Control-ïŹ‚ow abstractions - structured control-ïŹ‚ow: abstract over unstructured jumps - ‘go to statement considered harmful’ Edgser Dijkstra, 1968 Memory & Control Abstractions 13
  • 14. Example: C 14 int f = 1 int x = 5 int s = f + x while (x > 1) { f = x * f ; x = x - 1 } variable expression assignment control flow
  • 15. Example: Tiger 15 /* factorial function */ let var f := 1 var x := 5 var s := f + x in while x > 1 do ( f := x * f ; x := x - 1 ) end variable expression assignment control flow
  • 17. Control-ïŹ‚ow abstraction - Procedure: named unit of computation - Procedure call: jump to unit of computation and return Memory abstraction - Formal parameter: the name of the parameter - Actual parameter: value that is passed to procedure - Local variable: temporary memory Recursion - Procedure may (indirectly) call itself - Consequence? Procedural Abstraction 17
  • 18. Example: Procedures in C 18 #include <stio.h> /* factorial function */ int fac( int num ) { if (num < 1) return 1; else return num * fac(num - 1) ; } int main() { int x = 10 ; int f = fac( x ) ; int x printf(“%d! = %dn”, x, f); return 0; } formal parameter actual parameter local variable recursive call
  • 19. Procedures in Tiger 19 /* factorial function */ let function fac( n: int ) : int = let var f := 1 in if n < 1 then f := 1 else f := (n * fac(n - 1) ); f end var f := 0 var x := 5 in f := fac( x ) end formal parameter actual parameter local variable recursive call
  • 20. Stack - temporary storage - grows from high to low memory addresses - starts at SS Stack frames - return address - local variables - parameters - stack base: BP - stack top: SP Implementing Procedures with Stack and Stack Frames 20
  • 21. General purpose registers - accumulator AX - arithmetic operations - counter CX - shift/rotate instructions, loops - data DX - arithmetic operations, I/O - base BX - pointer to data - stack pointer SP, base pointer BP - top and base of stack - source SI, destination DI - stream operations Special purpose registers - segments SS, CS, DS, ES, FS, GS - ïŹ‚ags EFLAGS Reminder: Registers in x86 Family 21
  • 22. Example: Procedures in x86 Assembler 22 push 21 push 42 call _f add SP 8 push BP mov BP SP mov AX [BP + 8] mov DX [BP + 12] add AX DX pop BP ret pass parameter access parameter new stack frame old stack frame free parameters
  • 23. Caller - push parameters right-to-left on the stack - clean-up stack after call Callee - save old BP - initialise new BP - save registers - return result in AX - restore registers - restore BP Calling Conventions: CDECL 23 push 21 push 42 call _f add ESP 8 push EBP mov EBP ESP mov EAX [EBP + 8] mov EDX [EBP + 12] add EAX EDX pop EBP ret
  • 24. caller - push parameters right-to-left on the stack callee - save old BP - initialise new BP - save registers - return result in AX - restore registers - restore BP Calling Conventions: STDECL 24 push 21 push 42 call _f@8 push EBP mov EBP ESP mov EAX [EBP + 8] mov EDX [EBP + 12] add EAX EDX pop EBP ret 8
  • 25. Caller - passes parameters in registers - pushes additional parameters right-to-left ‹ on the stack Callee - save old BP, initialise new BP - save registers - return result in AX - restore registers - restore BP - cleans up the stack Calling Conventions: FASTCALL 25 mov ECX 21 mov EDX 42 call @f@8 push EBP mov EBP ESP mov EAX ECX add EAX EDX pop EBP ret
  • 26. Procedure declarations - in principle: full freedom - project constraints - target platform constraints Procedure calls - need to match procedure declarations Precompiled libraries - avoid recompilation - source code not always available Standardization - compilers / high-level languages standardize use of calling conventions - portable code: does not depend on particular calling convention Calling Conventions 26
  • 28. Objects - generalisation of records - identity - state - behaviour Messages - objects send and receive messages - trigger behaviour - imperative realisation: method calls Modularity: Objects & Messages 28
  • 29. Classes - generalisation of record types - characteristics of objects: attributes, ïŹelds, properties - behaviour of objects: methods, operations, features Encapsulation - interface exposure - hide attributes & methods - hide implementation Modularity: Classes 29 public class C { public int f1; private int f2; public void m1() { return; } private C m2(C c) { return c; } }
  • 30. Inheritance - inherit attributes & methods - additional attributes & methods - override behaviour - nominative subtyping Interfaces - avoid multiple inheritance - interface: contract for attributes & methods - class: provide attributes & methods - nominative subtyping Inheritance vs Interfaces 30 public class C { public int f1; public void m1() {
} public void m2() {
} } public class D extends C { public int f2; public void m2() {
} public void m3() {
} } public interface I { public int f; public void m(); } public class E implements I { public int f; public void m() {
} public void m’() {
} }
  • 31. Ad-hoc polymorphism - overloading ‣ same method name, independent classes ‣ same method name, same class, diïŹ€erent parameter types - overriding ‣ same method name, subclass, compatible types Universal polymorphism - subtype polymorphism ‣ inheritance, interfaces - parametric polymorphism Polymorphism 31
  • 32. Dispatch - link method call to method Static dispatch - type information at compile-time Dynamic dispatch - type information at run-time - single dispatch: one parameter - multiple dispatch: more parameters Static vs. Dynamic Dispatch 32
  • 33. Single Dispatch in Java 33 public class A {} public class B extends A {} public class C extends B {} public class D { public A m(A a) { System.out.println("D.m(A a)"); return a; } public A m(B b) { System.out.println("D.m(B b)"); return b; } } public class E extends D { public A m(A a) { System.out.println("E.m(A a)"); return a; } public B m(B b) { System.out.println("E.m(B b)"); return b; } } A a = new A(); B b = new B(); C c = new C(); D d = new D(); E e = new E(); A ab = b; A ac = c; D de = e; d. m(a); d. m(b); d. m(ab); d. m(c); d. m(ac); e. m(a); e. m(b); e. m(ab); e. m(c); e. m(ac); de.m(a); de.m(b); de.m(ab); de.m(c); de.m(ac);
  • 34. Methods - parameter types - return type Covariance - method in subclass - return type: subtype of original return type Contravariance - method in subclass - parameter types: supertypes of original parameter types Overriding 34
  • 35. Overloading vs Overriding 35 public class F { public A m(B b) { System.out.println("F.m(B b)"); return b; } } public class G extends F { public A m(A a) { System.out.println("G.m(A a)"); return a; } } public class H extends F { public B m(B b) { System.out.println("H.m(B b)"); return b; } } A a = new A(); B b = new B(); F f = new F(); G g = new G(); H h = new H(); A ab = b; f.m(b); g.m(a); g.m(b); g.m(ab); h.m(a); h.m(b); h.m(ab);
  • 36. Invariance 36 public class X { public A a; public A getA() { return a ; } public void setA(A a) { this.a = a ; } } public class Y extends X { public B a; public B getA() { return a ; } public void setA(B a) { this.a = a ; } } A a = new A(); B b = new B(); X y = new Y(); y.getA(); y.setA(b); y.setA(a); String[] s = new String[3] ; Object[] o = s ; o[1] = new A();
  • 38. Imperative languages - subroutines, routines, procedures, functions, methods - scoping: local variables - declarations with parameters (formal parameters) - calls with arguments (actual parameters) - pass by value, pass by reference Machine code - jumps: call and return - call stack: return address, parameters, private data - procedure prologue and epilogue Abstractions for Memory and Control 38
  • 39. Imperative languages - state & statements - abstraction over machine code - control ïŹ‚ow & procedures - types Object-oriented languages - objects & messages - classes - inheritance - types Imperative vs Object-Oriented 39
  • 48. 48 Reverse Engineering the JVM Instruction Set
  • 50. Bytecode Instructions: Goto 50 pc: 00 method area 00 01 02 03 04 05 06 A7 00 04 00 A7 FF FF goto 04 nop goto 03
  • 51. Bytecode Instructions: Goto 51 pc: 04 method area 00 01 02 03 04 05 06 A7 00 04 00 A7 FF FF goto 04 nop goto 03
  • 52. Bytecode Instructions: Goto 52 pc: 03 method area 00 01 02 03 04 05 06 A7 00 04 00 A7 FF FF goto 04 nop goto 03
  • 53. Bytecode Instructions: Goto 53 pc: 04 method area 00 01 02 03 04 05 06 A7 00 04 00 A7 FF FF goto 04 nop goto 03
  • 55. Operand Stack 55 pc: 00 00 01 02 03 04 05 06 pc: 00 optop: 00 00 01 02 03 04 05 06 04 05 10 2A 11 43 03 iconst_1 iconst_2 bipush sipush method area stack
  • 56. Operand Stack 56 optop: 01pc: 01 00 01 02 03 04 05 06 0000 000100 01 02 03 04 05 06 04 05 10 2A 11 43 03 iconst_1 iconst_2 bipush sipush method area stack
  • 57. Operand Stack 57 optop: 02pc: 02 00 01 02 03 04 05 06 0000 0001 0000 0002 00 01 02 03 04 05 06 04 05 10 2A 11 43 03 iconst_1 iconst_2 bipush sipush method area stack
  • 58. Operand Stack 58 optop: 03pc: 04 00 01 02 03 04 05 06 0000 0001 0000 0002 0000 002A 00 01 02 03 04 05 06 04 05 10 2A 11 43 03 iconst_1 iconst_2 bipush sipush method area stack
  • 59. Operand Stack 59 optop: 04pc: 07 00 01 02 03 04 05 06 0000 0001 0000 0002 0000 002A 0000 4303 00 01 02 03 04 05 06 04 05 10 2A 11 43 03 iconst_1 iconst_2 bipush sipush method area stack
  • 60. Operand Stack 60 optop: 04 00 01 02 03 04 05 06 0000 0001 0000 0002 0000 002A 0000 4303 pc: 07 07 08 09 0A 0B 0C 0D 60 68 5F 64 9A FF F5 iadd imul swap isub ifne 00 method area stack
  • 61. Operand Stack 61 optop: 03 00 01 02 03 04 05 06 0000 0001 0000 0002 0000 432D pc: 08 07 08 09 0A 0B 0C 0D 60 68 5F 64 9A FF F5 iadd imul swap isub ifne 00 method area stack
  • 62. Operand Stack 62 optop: 02 00 01 02 03 04 05 06 0000 0001 0000 865A pc: 09 07 08 09 0A 0B 0C 0D 60 68 5F 64 9A FF F5 iadd imul swap isub ifne 00 method area stack
  • 63. Operand Stack 63 optop: 02 00 01 02 03 04 05 06 0000 865A 0000 0001 pc: 0A 07 08 09 0A 0B 0C 0D 60 68 5F 64 9A FF F5 iadd imul swap isub ifne 00 method area stack
  • 64. Operand Stack 64 optop: 01 00 01 02 03 04 05 06 0000 8659 pc: 0B 07 08 09 0A 0B 0C 0D 60 68 5F 64 9A FF F5 iadd imul swap isub ifne 00 method area stack
  • 65. Operand Stack 65 00 01 02 03 04 05 06 pc: 00 optop: 00 00 01 02 03 04 05 06 04 05 10 2A 11 43 03 iconst_1 iconst_2 bipush sipush method area stack
  • 67. Constant Pool 67 pc: 00 method area stack 00 01 02 03 04 05 06 12 00 12 01 14 00 02 ldc 00 ldc 01 ldc2_w 02 00 01 02 03 04 05 06 constant pool 00 01 02 03 04 05 06 0000 002A 0000 4303 0000 0000 0000 002A optop: 00
  • 68. Constant Pool 68 pc: 02 method area stack 00 01 02 03 04 05 06 12 00 12 01 14 00 02 ldc 00 ldc 01 ldc2_w 02 00 01 02 03 04 05 06 0000 002A constant pool 00 01 02 03 04 05 06 0000 002A 0000 4303 0000 0000 0000 002A optop: 01
  • 69. Constant Pool 69 pc: 04 method area stack 00 01 02 03 04 05 06 12 00 12 01 14 00 02 ldc 00 ldc 01 ldc2_w 02 00 01 02 03 04 05 06 0000 002A 0000 4303 constant pool 00 01 02 03 04 05 06 0000 002A 0000 4303 0000 0000 0000 002A optop: 02
  • 70. Constant Pool 70 pc: 07 method area stack 00 01 02 03 04 05 06 12 00 12 01 14 00 02 ldc 00 ldc 01 ldc2_w 02 00 01 02 03 04 05 06 0000 002A 0000 4303 0000 0000 0000 002A constant pool 00 01 02 03 04 05 06 0000 002A 0000 4303 0000 0000 0000 002A optop: 04
  • 72. Local Variables 72 pc: 00 method area stack 00 01 02 03 04 05 06 04 3B 1A 3C 84 01 01 iconst_1 istore_0 iload_0 istore_1 iinc 01 01 00 01 02 03 04 05 06 local variables 00 01 02 03 04 05 06 optop: 00
  • 73. Local Variables 73 pc: 01 00 01 02 03 04 05 06 0000 0001 method area stack 00 01 02 03 04 05 06 04 3B 1A 3C 84 01 01 iconst_1 istore_0 iload_0 istore_1 iinc 01 01 local variables 00 01 02 03 04 05 06 optop: 01
  • 74. Local Variables 74 pc: 02 00 01 02 03 04 05 06 method area stack 00 01 02 03 04 05 06 04 3B 1A 3C 84 01 01 iconst_1 istore_0 iload_0 istore_1 iinc 01 01 local variables 00 01 02 03 04 05 06 0000 0001 optop: 00
  • 75. Local Variables 75 pc: 03 00 01 02 03 04 05 06 0000 0001 method area stack 00 01 02 03 04 05 06 04 3B 1A 3C 84 01 01 iconst_1 istore_0 iload_0 istore_1 iinc 01 01 local variables 00 01 02 03 04 05 06 0000 0001 optop: 01
  • 76. Local Variables 76 pc: 04 00 01 02 03 04 05 06 method area stack 00 01 02 03 04 05 06 04 3B 1A 3C 84 01 01 iconst_1 istore_0 iload_0 istore_1 iinc 01 01 local variables 00 01 02 03 04 05 06 0000 0001 0000 0001 optop: 00
  • 77. Local Variables 77 pc: 07 00 01 02 03 04 05 06 method area stack 00 01 02 03 04 05 06 04 3B 1A 3C 84 01 01 iconst_1 istore_0 iload_0 istore_1 iinc 01 01 local variables 00 01 02 03 04 05 06 0000 0001 0000 0002 optop: 00
  • 79. Heap 79 pc: 00 method area stack heap 4303 4303 "Compilers" 002A 002A [20,01,40,02,42] 00 01 02 03 04 05 06 12 00 19 00 12 01 2E ldc 00 aload 00 ldc 01 iaload 00 01 02 03 04 05 06 constant pool 00 01 02 03 04 05 06 4303 4303 0000 0004 local variables 00 01 02 03 04 05 06 002A 002A optop: 00
  • 80. Heap 80 pc: 02 method area stack heap 4303 4303 "Compilers" 002A 002A [20,01,40,02,42] 00 01 02 03 04 05 06 12 00 19 00 12 01 2E ldc 00 aload 00 ldc 01 iaload 00 01 02 03 04 05 06 4303 4303 constant pool 00 01 02 03 04 05 06 4303 4303 0000 0004 local variables 00 01 02 03 04 05 06 002A 002A optop: 01
  • 81. Heap 81 pc: 04 method area stack heap 4303 4303 "Compilers" 002A 002A [20,01,40,02,42] 00 01 02 03 04 05 06 12 00 19 00 12 01 2E ldc 00 aload 00 ldc 01 iaload 00 01 02 03 04 05 06 4303 4303 002A 002A constant pool 00 01 02 03 04 05 06 4303 4303 0000 0004 local variables 00 01 02 03 04 05 06 002A 002A optop: 02
  • 82. Heap 82 pc: 06 method area stack heap 4303 4303 "Compilers" 002A 002A [20,01,40,02,42] 00 01 02 03 04 05 06 12 00 19 00 12 01 2E ldc 00 aload 00 ldc 01 iaload 00 01 02 03 04 05 06 4303 4303 002A 002A 0000 0004 constant pool 00 01 02 03 04 05 06 4303 4303 0000 0004 local variables 00 01 02 03 04 05 06 002A 002A optop: 03
  • 83. Heap 83 pc: 07 method area stack heap 4303 4303 "Compilers" 002A 002A [20,01,40,02,42] 00 01 02 03 04 05 06 12 00 19 00 12 01 2E ldc 00 aload 00 ldc 01 iaload 00 01 02 03 04 05 06 4303 4303 0000 0042 constant pool 00 01 02 03 04 05 06 4303 4303 0000 0004 local variables 00 01 02 03 04 05 06 002A 002A optop: 02
  • 85. Dispatch - link method call to method Static dispatch - type information at compile-time Dynamic dispatch - type information at run-time - single dispatch: one parameter - multiple dispatch: more parameters Static vs. Dynamic Dispatch 85
  • 86. Example: Static Call 86 .class public Exp .method public static fac(I)I iload 1 ifne else iconst_1 ireturn else: iload 1 dup iconst_1 isub invokestatic Exp/fac(I)I imul ireturn .end method function fac(n: int): int= if n = 0 then 1 else n * fac(n - 1)
  • 87. Example: Dynamic Call 87 .class public Exp .method public fac(I)I iload 1 ifne else iconst_1 ireturn else: iload 0 iload 1 dup iconst_1 isub invokevirtual Exp/fac(I)I imul ireturn .end method function fac(n: int): int= if n = 0 then 1 else n * fac(n - 1)
  • 88. Caller - push object - push parameters left-to-right - call method Virtual machine on call - allocate space (frame data, operand stack, local variables) - store frame data (data pointer, return address, exception table) - store parameters as local variables - dynamic dispatch - point pc to method code Code Pattern: Dynamic Method Call 88
  • 89. Callee - parameters in local variables - leave result on operand stack - return to caller Virtual machine on return - push result on caller’s operand stack - point pc to return address - destroy frame Code Pattern: Return from Method Call 89
  • 92. Stack Frames 92 00 01 02 03 04 05 06 2A 10 40 B6 00 01 AC aload_0 bipush invokevirtual 01 ireturn optop: 02 method area stack heap 00 01 02 03 04 05 06 4303 4303 0000 0040 local variables 00 01 02 03 04 05 06 4303 4303 pc: 03
  • 93. Stack Frames 93 pc: 80 80 81 82 83 84 85 86 2B 59 68 AC 00 00 00 iload_1 dup imul ireturn optop: 01 method area stack heap 00 01 02 03 04 05 06 4303 4303 0000 0040 local variables 00 01 02 03 04 05 06 4303 4303 local variables 00 01 02 03 04 05 06 4303 4303 0000 0040 optop: 00 stack 00 01 02 03 04 05 06
  • 94. Stack Frames 94 pc: 81 80 81 82 83 84 85 86 2B 59 68 AC 00 00 00 iload_1 dup imul ireturn optop: 01 method area stack heap 00 01 02 03 04 05 06 4303 4303 0000 0040 local variables 00 01 02 03 04 05 06 4303 4303 local variables 00 01 02 03 04 05 06 4303 4303 0000 0040 optop: 01 stack 00 01 02 03 04 05 06 0000 0040
  • 95. Stack Frames 95 pc: 81 80 81 82 83 84 85 86 2B 59 68 AC 00 00 00 iload_1 dup imul ireturn optop: 01 method area stack heap 00 01 02 03 04 05 06 4303 4303 0000 0040 local variables 00 01 02 03 04 05 06 4303 4303 local variables 00 01 02 03 04 05 06 4303 4303 0000 0040 optop: 02 stack 00 01 02 03 04 05 06 0000 0040 0000 0040
  • 96. Stack Frames 96 pc: 82 80 81 82 83 84 85 86 2B 59 68 AC 00 00 00 iload_1 dup imul ireturn optop: 01 method area stack heap 00 01 02 03 04 05 06 4303 4303 0000 0040 local variables 00 01 02 03 04 05 06 4303 4303 local variables 00 01 02 03 04 05 06 4303 4303 0000 0040 optop: 01 stack 00 01 02 03 04 05 06 0000 1000
  • 97. Stack Frames 97 00 01 02 03 04 05 06 2A 10 40 B6 00 01 AC aload_0 bipush invokevirtual 01 ireturn optop: 01 method area stack heap 00 01 02 03 04 05 06 0000 1000 local variables 00 01 02 03 04 05 06 4303 4303 pc: 06
  • 99. Java Compiler 99 > ls Course.java > javac -verbose Course.java [parsing started Course.java] [parsing completed 8ms] [loading java/lang/Object.class(java/lang:Object.class)] [checking university.Course] [wrote Course.class] [total 411ms] > ls Course.class Course.java
  • 100. Class Files: Format 100 magic number CAFEBABE class file version (minor, major) constant pool count + constant pool access flags this class super class interfaces count + interfaces fields count + fields methods count + methods attribute count + attributes
  • 101. Jasmin Intermediate Language 101 .class public Exp .method public static fac(I)I iload 1 ifne else iconst_1 ireturn else: iload 1 dup iconst_1 isub invokestatic Exp/fac(I)I imul ireturn .end method
  • 103. Reasons - code overhead - execution overhead Inlining - replace calls by body of the procedure - source code level Tail recursion - replace recursive calls by loops or jumps - source or machine code level Optimizations 103
  • 104. Code Generation 104 function fac0(n0: int): int= if n0 = 0 then 1 else n0 * fac0(n0 - 1) .method public static fac0(I)I iload 1 ldc 0 if_icmpeq label0 ldc 0 goto label1 label0: ldc 1 label1: ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
  • 105. Optimization 105 .method public static fac0(I)I iload_1 ifne else0 iconst_1 ireturn else0: iload_1 dup iconst_1 isub invokestatic Exp/fac0(I)I imul ireturn .end method .method public static fac0(I)I iload 1 ldc 0 if_icmpeq label0 ldc 0 goto label1 label0: ldc 1 label1: ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
  • 106. Optimization 106 .method public static fac0(I)I iload 1 ifeq label0 ldc 0 goto label1 label0: ldc 1 label1: ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method .method public static fac0(I)I iload 1 ldc 0 if_icmpeq label0 ldc 0 goto label1 label0: ldc 1 label1: ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
  • 107. Optimization 107 .method public static fac0(I)I iload 1 ifeq label0 ldc 0 ifeq else0 label0: ldc 1 label1: ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method .method public static fac0(I)I iload 1 ifeq label0 ldc 0 goto label1 label0: ldc 1 label1: ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
  • 108. Optimization 108 .method public static fac0(I)I iload 1 ifeq label0 goto else0 label0: ldc 1 label1: ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method .method public static fac0(I)I iload 1 ifeq label0 ldc 0 ifeq else0 label0: ldc 1 label1: ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
  • 109. Optimization 109 .method public static fac0(I)I iload 1 ifeq label0 goto else0 label0: ldc 1 ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method .method public static fac0(I)I iload 1 ifeq label0 goto else0 label0: ldc 1 label1: ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
  • 110. Optimization 110 .method public static fac0(I)I iload 1 ifeq label0 goto else0 label0: ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method .method public static fac0(I)I iload 1 ifeq label0 goto else0 label0: ldc 1 ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
  • 111. Optimization 111 .method public static fac0(I)I iload 1 ifneq else0 label0: ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method .method public static fac0(I)I iload 1 ifeq label0 goto else0 label0: ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
  • 112. Optimization 112 .method public static fac0(I)I iload 1 ifneq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method .method public static fac0(I)I iload 1 ifneq else0 label0: ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
  • 113. Optimization 113 .method public static fac0(I)I iload 1 ifneq else0 ldc 1 ireturn else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method .method public static fac0(I)I iload 1 ifneq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
  • 114. Optimization 114 .method public static fac0(I)I iload 1 ifneq else0 ldc 1 ireturn else0: iload 1 dup ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method .method public static fac0(I)I iload 1 ifneq else0 ldc 1 ireturn else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
  • 115. Optimization 115 .method public static fac0(I)I iload_1 ifneq else0 ldc 1 ireturn else0: iload_1 dup ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method .method public static fac0(I)I iload 1 ifneq else0 ldc 1 ireturn else0: iload 1 dup ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
  • 116. Optimization 116 .method public static fac0(I)I iload_1 ifneq else0 iconst_1 ireturn else0: iload_1 dup iconst_1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method .method public static fac0(I)I iload_1 ifneq else0 ldc 1 ireturn else0: iload_1 dup ldc 1 isub invokestatic Exp/fac0(I)I imul end0: ireturn .end method
  • 118. Example: Tail Recursion 118 .class public Exp .method public static fac(I)I iload 1 ifne else iconst_1 ireturn else: iload 1 dup iconst_1 isub invokestatic Exp/fac(I)I imul ireturn .end method
  • 119. Example: Tail Recursion 119 .class public Exp .method public static fac(I)I iload 1 ifne else iconst_1 ireturn else: iload 1 dup iconst_1 isub invokestatic Exp/fac(I)I imul ireturn .end method .class public Exp .method public static fac(II)I iload 1 ifne else iload 2 ireturn else: iload 1 iconst_1 isub iload 1 iload 2 imul invokestatic Exp/fac(II)I ireturn .end method
  • 120. Example: Tail Recursion 120 .class public Exp .method public static fac(II)I iload 1 ifne else iload 2 ireturn else: iload 1 iconst_1 isub iload 1 iload 2 imul invokestatic Exp/fac(II)I ireturn .end method .class public Exp .method public static fac(II)I strt: iload 1 ifne else iload 2 ireturn else: iload 1 iconst_1 isub iload 1 iload 2 imul istore 2 istore 1 goto strt
  • 122. Printing Strings 122 to-jbc = ?Nil() ; <printstring> "aconst_nulln" to-jbc = ?NoVal() ; <printstring> "nopn" to-jbc = ?Seq(es) ; <list-loop(to-jbc)> es to-jbc = ?Int(i); <printstring> "ldc "; <printstring> i; <printstring> "n" to-jbc = ?Bop(op, e1, e2) ; <to-jbc> e1 ; <to-jbc> e2 ; <to-jbc> op to-jbc = ?PLUS() ; <printstring> "iaddn" to-jbc = ?MINUS() ; <printstring> "isubn" to-jbc = ?MUL() ; <printstring> "imuln" to-jbc = ?DIV() ; <printstring> "idivn"
  • 123. String Concatenation 123 to-jbc: Nil() -> "aconst_nulln" to-jbc: NoVal() -> "nopn" to-jbc: Seq(es) -> <concat-strings> <map(to-jbc)> es to-jbc: Int(i) -> <concat-strings> ["ldc ", i, "n"] to-jbc: Bop(op, e1, e2) -> <concat-strings> [ <to-jbc> e1, <to-jbc> e2, <to-jbc> op ] to-jbc: PLUS() -> "iaddn" to-jbc: MINUS() -> "isubn" to-jbc: MUL() -> "imuln" to-jbc: DIV() -> "idivn"
  • 124. String Interpolation 124 to-jbc: Nil() -> $[aconst_null] to-jbc: NoVal() -> $[nop] to-jbc: Seq(es) -> <map-to-jbc> es map-to-jbc: [] -> $[] map-to-jbc: [h|t] -> $[[<to-jbc> h] [<map-to-jbc> t]] to-jbc: Int(i) -> $[ldc [i]]
 to-jbc: Bop(op, e1, e2) -> $[[<to-jbc> e1] [<to-jbc> e2] [<to-jbc> op]] to-jbc: PLUS() -> $[iadd] to-jbc: MINUS() -> $[isub] to-jbc: MUL() -> $[imul] to-jbc: DIV() -> $[idiv]
  • 126. Compilation by Transformation 126 backend frontend parse desugar analyse normalise generate optimise format
  • 127. Transformation 127 to-jbc: Nil() -> [ ACONST_NULL() ] to-jbc: NoVal() -> [ NOP() ] to-jbc: Seq(es) -> <mapconcat(to-jbc)> es to-jbc: Int(i) -> [ LDC(Int(i)) ] to-jbc: String(s) -> [ LDC(String(s)) ] to-jbc: Bop(op, e1, e2) -> <mapconcat(to-jbc)> [ e1, e2, op ] to-jbc: PLUS() -> [ IADD() ] to-jbc: MINUS() -> [ ISUB() ] to-jbc: MUL() -> [ IMUL() ] to-jbc: DIV() -> [ IDIV() ] to-jbc: Assign(lhs, e) -> <concat> [ <to-jbc> e, <lhs-to-jbc> lhs ] to-jbc: Var(x) -> [ ILOAD(x) ] where <type-of> Var(x) => INT() to-jbc: Var(x) -> [ ALOAD(x) ] where <type-of> Var(x) => STRING() lhs-to-jbc: Var(x) -> [ ISTORE(x) ] where <type-of> Var(x) => INT() lhs-to-jbc: Var(x) -> [ ASTORE(x) ] where <type-of> Var(x) => STRING()
  • 128. Transformation 128 to-jbc: IfThenElse(e1, e2, e3) -> <concat> [ <to-jbc> e1 , [ IFEQ(LabelRef(else)) ] , <to-jbc> e2 , [ GOTO(LabelRef(end)), Label(else) ] , <to-jbc> e3 , [ Label(end) ] ] where <newname> "else" => else where <newname> "end" => end to-jbc: While(e1, e2) -> <concat>[ [ GOTO(LabelRef(check)), Label(body) ] , <to-jbc> e2 , [ Label(check) ] , <to-jbc> e1 , [ IFNE(LabelRef(body)) ] ] where <newname> "test" => check where <newname> "body" => body
  • 129. Transformation: Example 129 function fac(n: int): int= if n = 0 then 1 else n * fac(n - 1) .method public static fac(I)I iload 1 ldc 0 if_icmpeq label0 ldc 0 goto label1 label0: ldc 1 label1: ifeq else0 ldc 1 goto end0 else0: iload 1 iload 1 ldc 1 isub invokestatic Exp/fac(I)I imul end0: ireturn .end method
  • 132. Back-End - Lecture 11: DataïŹ‚ow Analysis (Nov 28) - Lecture 12: Garbage Collection (Dec 5) - Lecture 13: Just-in-Time Compilation (Interpreters & Partial Evaluation) (Dec 12) Parsing - Lecture 14: LL Parsing (Dec 19) - Lecture 15: LR Parsing (Jan 9) Lab - Lab 6: Testing Type Analysis (Nov 22) - Lab 7: Type Analyis (Dec 6) - Lab 8: Compiling Minimal Programs (Dec 13) - Lab 9: Compiling Expressions and Statements (Dec 22) - Lab 10: Compiling Fields, Parameters, and Variables (Jan 19) Next 132
  • 133. 133