[Bug lto/104617] New: Bug in handling of 64k+ sections

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104617

            Bug ID: 104617
           Summary: Bug in handling of 64k+ sections
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: lto
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jakub at gcc dot gnu.org
                CC: marxin at gcc dot gnu.org
  Target Milestone: ---

When foo1.c is:
#define A(n) int foo1##n(void) { return 1##n; }
#define B(n) A(n##0) A(n##1) A(n##2) A(n##3) A(n##4) A(n##5) A(n##6) A(n##7)
A(n##8) A(n##9)
#define C(n) B(n##0) B(n##1) B(n##2) B(n##3) B(n##4) B(n##5) B(n##6) B(n##7)
B(n##8) B(n##9)
#define D(n) C(n##0) C(n##1) C(n##2) C(n##3) C(n##4) C(n##5) C(n##6) C(n##7)
C(n##8) C(n##9)
#define E(n) D(n##0) D(n##1) D(n##2) D(n##3) D(n##4) D(n##5) D(n##6) D(n##7)
D(n##8) D(n##9)
E(0) E(1) E(2) D(30) D(31) C(320) C(321) C(322) C(323) C(324) C(325)
B(3260) B(3261) B(3262) B(3263) A(32640) A(32641) A(32642)
and I compile it like:
./xgcc -B ./ -c -g -fpic -ffat-lto-objects -flto  -O0 -o foo1.o foo1.c
-ffunction-sections
./xgcc -B ./ -shared -g -fpic -flto -O0 -o foo1.so foo1.o
/tmp/ccTW8mBm.debug.temp.o: file not recognized: file format not recognized

If I add -save-temps, and
readelf -WS foo1.o.debug.temp.o
I see various errors:
readelf: foo1.o.debug.temp.o: Warning: Section 2 has an out of range sh_link
value of 65321
readelf: foo1.o.debug.temp.o: Warning: Section 5 has an out of range sh_link
value of 65321
readelf: foo1.o.debug.temp.o: Warning: Section 10 has an out of range sh_link
value of 65323
There are 13 section headers, starting at offset 0x40:
readelf: foo1.o.debug.temp.o: Warning: [ 2]: Link field (65321) should index a
symtab section.
readelf: foo1.o.debug.temp.o: Warning: [ 5]: Link field (65321) should index a
symtab section.
readelf: foo1.o.debug.temp.o: Warning: [10]: Link field (65323) should index a
string section.

Section Headers:
  [Nr] Name              Type            Address          Off    Size   ES Flg
Lk Inf Al
  [ 0]                   NULL            0000000000000000 000000 000000 00     
0   0  0
  [ 1] .debug_info       PROGBITS        0000000000000000 000380 057ac7 00     
0   0  1
  [ 2] .rela.debug_info  RELA            0000000000000000 057e48 0bf4c0 18   I
65321   1  8
  [ 3] .debug_abbrev     PROGBITS        0000000000000000 117308 00002f 00     
0   0  1
  [ 4] .debug_line       PROGBITS        0000000000000000 117337 000036 00     
0   0  1
  [ 5] .rela.debug_line  RELA            0000000000000000 117370 000048 18   I
65321   4  8
  [ 6] .debug_str        PROGBITS        0000000000000000 1173b8 04fbb7 01  MS 
0   0  1
  [ 7] .debug_line_str   PROGBITS        0000000000000000 166f6f 00001c 01  MS 
0   0  1
  [ 8] .comment          PROGBITS        0000000000000000 166f8b 00002b 01  MS 
0   0  1
  [ 9] .note.GNU-stack   PROGBITS        0000000000000000 166fb6 000000 00     
0   0  1
  [10] .symtab           SYMTAB          0000000000000000 166fb8 23dfa8 18    
65323 65315  8
  [11] .strtab           STRTAB          0000000000000000 3a4f60 04fb36 00     
0   0  1
  [12] .shstrtab         STRTAB          0000000000000000 3f4a96 000097 00     
0   0  1
Key to Flags:
  W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
  L (link order), O (extra OS processing required), G (group), T (TLS),
  C (compressed), x (unknown), o (OS specific), E (exclude),
  l (large), p (processor specific)

The sh_link fields containing 65321 looks to be a bug, it should be 10 instead.
65323 should be 11 (index of .strtab), 65315 is probably ok (that is how many
STB_LOCAL symbols are in .symtab).