COOL compiler note

COOL_compiler_note.md

Backend

IR -> IR Optimization -> Code Generation(Register allocation/Instruction selection) Assembly

Code generation

1.top-of-stack caching (1-TOSCA)
2.init garbage collector

Object layout

1.similar to C++ inheritance
2.gc in COOL runtime
3.Class Tag, Object Size, Dispatch table pointer (similar to C++ vptr), Dispatch table (similar to C++ vtable)
4.register allocation is Graph coloring
(Linear-Scan Register Allocation is another way to allocate registers)

IR

1.Three-address code (it doesn't be implemented in this course)

Runtime

1.it contains a concurrent garbage collector
2.the management of application memory
3.how the program accesses variables, mechanisms for passing parameters between procedures
4.interfacing with the operating system
5.The compiler makes assumptions depending on the specific runtime system to generate correct code.

GC (cgen.cc)

gc is also part of the program

Questions

1.gc in runtime
2.how gc works
3.stack-based virtual machine -> register-based virtual machine (?
4.code generation
4-1. stack based machine
4-2. register based machine
-> register allocation and assignment
-> instruction selection/instruction scheduling
5. how to verify and test compiler?

shell script

10.1. Manipulating Strings: Substring Removal
How do I parse command line arguments in Bash?

known issues

1. How to work under ASLR ? (fPIC?)
2. stdin/stdout is hardcoded. (Type: R_AARCH64_COPY)
3. fflush(stdin) before fgets (problem)
4. Under GC mode, Program received signal SIGSEGV, Segmentation fault. _GenGC_MajorC_stackloop () at trap_handler_aarch64.s

(gdb)x/xg is equivalent to x/2xw (g: 8-byte, w: 4-byte)

0xfffffffffad0: 0x0040128c
(gdb) x/4xw 0xfffffad0