[Advanced Compiler Lecture Notes]
Week 02 (2003/9/22)

1. 1> standard output
   2> standard error

2. The GCC making process (bootstrap)
Example: GCC-old means gcc 2.95; GCC-new means gcc 3.1.1
Stage 1:
	Tool: GCC-old binary
	Input: GCC-new source
	Output: GCC-new binary#1
Stage 2:
	Tool: GCC-new binary#1
	Input: GCC-new source
	Output: GCC-new binary#2
Stage 3:
	Tool: GCC-new binary#2
	Input: GCC-new source
	Output: GCC-new binary#3
The output of phase 2 and phase 3 should be the identical; if not, the bootstrap step fails.
The final GCC executable file would be GCC-new binary#3 (same as GCC-new binary#2).

3. The GCC invocation process
Example: Executable files are with ".exe" extension here, and the GCC is build only for C language.
Step 1: gcc.exe parses command options (according to gccspec)
Step 2: gcc.exe forks cpp.exe (from cppmain.c)
Step 3: cpp.exe forks cc1.exe (from main.c)

4. CPP: C Pre-Processor

5. The brief structure of GCC:
[pre-processor] -> [scanner + parser](language-dependent) -> [backend](machine dependent)

6. About gengentrl (generate generate register transfer language)
gengentrl.c --> genrtl.c (the kernel of GCC)
            --> genrtl.h

7. On object and library
An object file is with ".o" extension on Linux.
An library file is with ".a" extension on Linux.
To make a library file: ar -rc xxx.a aaa.o bbb.o ....

8. What's inside libbackend.a?
Common backend objects (fron download)
Common dependent objects (from genxxx.c and genxxx.h files)
Machine dependent objects (fron download)

9. make -d: to print out debugging information when executing Makefile