Add dwarf support

The new gcc12 release does not support stabs any more.
This was a good reason to add support for dwarf.

The stabs code still works and is used if configure option --dwarf
is not used.

Tested on x86_64, i386, arm, arm64, riscv64 with dwarf-5.
Some debuggers may not support dwarf-5. Try using older dwarf versions
i that case.
The tccmacho.c code probably need some support for dwarf.

arm-gen.c, arm64-gen.c, i386-gen.c, riscv64-gen.c, x86_64-gen.
- fix get_sym_ref symbol size

arm-link.c, arm64-link.c, i386-link.c, riscv64-link.c, x86_64-link.c
- add R_DATA_32U

libtcc.c:
- parse -gdwarf option

tcc.c:
- add dwarf option

tcc.h:
- add dwarf option and sections

tccelf.c:
- init dwarf sections
- avoid adding sh_addr for dwarf sections
- remove dwarf relocs for output dll
- add dwarf sections for tccrun

tccgen.c:
- add dwarf defines + global data
- add dwarf_* functions
- mix dwarf code with stabs code
- a trick is used to emit function name in .debug_line section so
  only this section has to be parsed instead of .debug_info and
  .debug_abbrev.
- fix init debug_modes

tccrun.c:
- add dwarf sections in rt_context
- init them in tcc_run
- add new dwarf code rt_printline_dwarf to find file/function

dwarf.h:
- New file

tcc-doc.texi:
- document dwarf

configure:
- add dwarf option

lib/Makefile
- change -gstabs into -gdwarf

lib/bt-exe.c, tests/tests2/Makefile, tests/tests2/126_bound_global:
- Add __bound_init call
- Add new testcase to test it

.gitignore

@@ -24,6 +24,7 @@ config*.h
 config*.mak
 config.texi
 conftest*
+c2str
 tags
 TAGS
 tcc.1

arm-gen.c

@@ -866,7 +866,7 @@ static void gen_bounds_epilog(void)
     *bounds_ptr = 0;
 
     sym_data = get_sym_ref(&char_pointer_type, lbounds_section,
-                           func_bound_offset, lbounds_section->data_offset);
+                           func_bound_offset, PTR_SIZE);
 
     /* generate bound local allocation */
     if (offset_modified) {

arm-link.c

@@ -4,6 +4,7 @@
 
 /* relocation type for 32 bit data relocation */
 #define R_DATA_32   R_ARM_ABS32
+#define R_DATA_32U  R_ARM_ABS32
 #define R_DATA_PTR  R_ARM_ABS32
 #define R_JMP_SLOT  R_ARM_JUMP_SLOT
 #define R_GLOB_DAT  R_ARM_GLOB_DAT

arm64-gen.c

@@ -710,7 +710,7 @@ static void gen_bounds_epilog(void)
     *bounds_ptr = 0;
 
     sym_data = get_sym_ref(&char_pointer_type, lbounds_section,
-                           func_bound_offset, lbounds_section->data_offset);
+                           func_bound_offset, PTR_SIZE);
 
     /* generate bound local allocation */
     if (offset_modified) {

arm64-link.c

@@ -3,6 +3,7 @@
 #define EM_TCC_TARGET EM_AARCH64
 
 #define R_DATA_32  R_AARCH64_ABS32
+#define R_DATA_32U R_AARCH64_ABS32
 #define R_DATA_PTR R_AARCH64_ABS64
 #define R_JMP_SLOT R_AARCH64_JUMP_SLOT
 #define R_GLOB_DAT R_AARCH64_GLOB_DAT

c67-link.c

@@ -4,6 +4,7 @@
 
 /* relocation type for 32 bit data relocation */
 #define R_DATA_32   R_C60_32
+#define R_DATA_32U  R_C60_32
 #define R_DATA_PTR  R_C60_32
 #define R_JMP_SLOT  R_C60_JMP_SLOT
 #define R_GLOB_DAT  R_C60_GLOB_DAT

configure

@@ -51,6 +51,7 @@ ar_set=
 darwin=
 cpu=
 cpuver=
+dwarf=
 
 # OS specific
 cpu_sys=`uname -m`
@@ -136,6 +137,8 @@ for opt do
   ;;
   --cpu=*) cpu=`echo $opt | cut -d '=' -f 2-`
   ;;
+  --dwarf=*) dwarf=`echo $opt | cut -d '=' -f 2-`
+  ;;
   --enable-cross) confvars="$confvars cross"
   ;;
   --disable-static) confvars="$confvars static=no"
@@ -328,6 +331,7 @@ Advanced options (experts only):
   --config-backtrace=no    disable stack backtraces (with -run or -bt)
   --config-bcheck=no       disable bounds checker (-b)
   --config-predefs=no      do not compile tccdefs.h, instead just include
+  --dwarf=x                Use dwarf debug info instead of stabs (x=2..5)
 EOF
 exit 1
 fi
@@ -493,6 +497,7 @@ print_mak CONFIG_TCC_ELFINTERP "$tcc_elfinterp"
 print_mak CONFIG_LDDIR "$tcc_lddir"
 print_mak CONFIG_TRIPLET "$triplet"
 print_mak TCC_CPU_VERSION "$cpuver" num
+print_mak CONFIG_DWARF "$dwarf"
 
 echo "ARCH=$cpu" >> config.mak
 echo "TARGETOS=$targetos" >> config.mak