COMPILER CONSTRUCTION Principles and practice Kenneth C. louden
COMPILER CONSTRUCTION Principles and Practice Kenneth C. Louden
8. Code Generation
8. Code Generation
Contents Part One 8. 1 Intermediate Code and Data Structure for code Generation 8.2 Basic Code Generation Techniques Part Two 8.3 Code generation of data Structure Reference 8.4 Code generation of Control Statements and logical Expression 8.5 Code generation of procedure and function calls Part Three 8.6 Code Generation on Commercial Compilers: Two Case studies 8.7TM: A Simple Target Machine 8.8 A Code Generator for the TINY Language 8.9A Survey of Code optimization Techniques 8.10 Simple Optimizations for tINY Code Generator
Contents Part One 8.1 Intermediate Code and Data Structure for code Generation 8.2 Basic Code Generation Techniques Part Two 8.3 Code Generation of Data Structure Reference 8.4 Code Generation of Control Statements and Logical Expression 8.5 Code Generation of Procedure and Function calls Part Three 8.6 Code Generation on Commercial Compilers: Two Case Studies 8.7 TM: A Simple Target Machine 8.8 A Code Generator for the TINY Language 8.9 A Survey of Code Optimization Techniques 8.10 Simple Optimizations for TINY Code Generator
8. 6 Code generation in commercial Compilers: Two Case Studies Borlands c compiler for 80X86 Suns c compiler for sparc Stations
8.6 Code Generation in Commercial Compilers: Two Case Studies Borland’s C Compiler for 80X86 Sun’s C Compiler for SparcStations
For example, onsider the c procedure Void f( int char c) i int a[10; double y;
For example, Consider the C procedure Void f ( int x, char c) { int a[10]; double y; … }
The activation record for a call to f would appear as Offset ofx Control linl fp Offset of c Return address a0] Offset of a Offset of
Offset of x fp Offset of c Offset of a Offset of y The activation record for a call to f would appear as x c Control link Return address a[9] … a[1] a[0] y
Assuming two bytes for integers, four bytes for addresses one byte for character and eight bytes for double-precision floating point, we would have the following offset values Name Offset +5 +4 24 32 Now, an access of, would require the computation of the address (-24+2*1)(fp)
Name Offset x +5 c +4 a -24 y -32 Assuming two bytes for integers, four bytes for addresses, one byte for character and eight bytes for double-precision floating point, we would have the following offset values: Now, an access of a[i], would require the computation of the address: (-24+2*i)(fp)
For the expression: (X=X+3)+ 4, the p code and three-address code Lad x Lod x Ldc 3 Adi t1=x+3 Stn X=tl Ldc 4 Adi t2=t1+4
• For the expression: ( x = x +3 ) + 4, the pcode and three-address code: Lad x Lod x Ldc 3 Adi t1=x+3 Stn x=t1 Ldc 4 Adi t2=t1+4
8.6.1 The borland 3.0 C Compiler for the 80X86
8.6.1 The Borland 3.0 C Compiler for the 80X86
Consider the examples of the output of this compiler with the following assignment (X=x+3)+4 The assembly code for this expression as produced by the borland 3.0 compiler for the Intel 80X86 is as follows mov ax, word ptr [bp-2 add ax. 3 mov word ptr [bp-2, ax add ax. 4 Notes The bp is used as the frame pointer The static simulation method is used to convert the intermediate code into the target code
• Consider the examples of the output of this compiler with the following assignment (x = x +3 ) + 4 • The assembly code for this expression as produced by the Borland 3.0 compiler for the Intel 80x86 is as follows: mov ax, word ptr [bp-2] add ax, 3 mov word ptr [bp-2], ax add ax, 4 • Notes: – The bp is used as the frame pointer. – The static simulation method is used to convert the intermediate code into the target code
