[ELF] - Use error() instead of fatal() during relaxation of R_X86_64_GOTTPOFF

[grimar]

Summary

This is last known noticable fatal() in target.cpp.
We also have other ones for unknown relocations or
creating unknown targets, but that one can be just error I think.

Used yaml2obj to generate test.

[davide]

I guess this is OK once you address my comment.

test/ELF/invalid/broken-relaxation-x64.s

1–8 ↗

(On Diff #82318)

Please add a comment explaining how you generated this file (so that people unfamiliar with YAML can understand).

[grimar]

test/ELF/invalid/broken-relaxation-x64.s

1–8 ↗

(On Diff #82318)

hmm, ok. I am going to add something like that then:

* Yaml below contains 2 relocations of type R_X86_64_GOTTPOFF, and a .text with fake content filled by 0xFF.
That means instructions for relaxation are "broken", so they does not match any known valid relaxations.
We also generate .tls section because we need it for correct proccessing of STT_TLS symbol.

lld/trunk/ELF/Target.cpp

if (memcmp(Inst, "\x48\x03\x25", 3) == 0) {
     // "movq foo@gottpoff(%rip),%r[8-15]" -> "movq $foo,%r[8-15]"
     memcpy(Inst, "\x49\xc7", 2);
     *RegSlot = 0xc0 | Reg;
   } else if (memcmp(Inst, "\x48\x8b", 2) == 0) {
     // "movq foo@gottpoff(%rip),%reg" -> "movq $foo,%reg"
     memcpy(Inst, "\x48\xc7", 2);
     *RegSlot = 0xc0 | Reg;
   } else {
-    fatal(getErrorLocation(Loc - 3) +
+    error(getErrorLocation(Loc - 3) +
           "R_X86_64_GOTTPOFF must be used in MOVQ or ADDQ instructions only");
   }
 
   // The original code used a PC relative relocation.
   // Need to compensate for the -4 it had in the addend.
   relocateOne(Loc, R_X86_64_TPOFF32, Val + 4);
 }
 

lld/trunk/test/ELF/invalid/broken-relaxation-x64.s

+# REQUIRES: x86
+
+# RUN: yaml2obj %s -o %t.o
+# RUN: not ld.lld %t.o -o %t.exe 2>&1 | FileCheck --check-prefix=ERR %s
+# ERR: R_X86_64_GOTTPOFF must be used in MOVQ or ADDQ instructions only
+# ERR: R_X86_64_GOTTPOFF must be used in MOVQ or ADDQ instructions only
+
+## YAML below contains 2 relocations of type R_X86_64_GOTTPOFF, and a .text
+## with fake content filled by 0xFF. That means instructions for relaxation are
+## "broken", so they does not match any known valid relaxations. We also generate
+## .tls section because we need it for correct proccessing of STT_TLS symbol.
+!ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  OSABI:           ELFOSABI_FREEBSD
+  Type:            ET_REL
+  Machine:         EM_X86_64
+Sections:
+  - Type:            SHT_PROGBITS
+    Name:            .text
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
+    AddressAlign:    0x04
+    Content:         "FFFFFFFFFFFFFFFF"
+  - Type:            SHT_PROGBITS
+    Name:            .tls
+    Flags:           [ SHF_ALLOC, SHF_TLS ]
+  - Type:            SHT_REL
+    Name:            .rel.text
+    Link:            .symtab
+    Info:            .text
+    AddressAlign:    0x04
+    Relocations:
+      - Offset:          4
+        Symbol:          foo
+        Type:            R_X86_64_GOTTPOFF
+      - Offset:          4
+        Symbol:          foo
+        Type:            R_X86_64_GOTTPOFF
+Symbols:
+  Global:
+    - Name:     foo
+      Type:     STT_TLS
+      Section:  .text
+      Value:    0x12345
+      Size:     4