[lld/ELF][X86] Respect outSecOff when checking if GOTPCREL can be relaxed (#86334)

The existing implementation didn't handle when the input text section
was some offset from the output section.

This resulted in an assert in relaxGot() with an lld built with asserts
for some large binaries, or even worse, a silently broken binary with an
lld without asserts.

(cherry picked from commit 48048051323d5dd74057dc5f32df8c3c323afcd5)

diff --git a/lld/ELF/Arch/X86_64.cpp b/lld/ELF/Arch/X86_64.cpp
index de459013595fed86e25608c91f151a772faef250..a85bf3aa0c09d11ed39a0eb351321c8f839dd587 100644 (file)
--- a/lld/ELF/Arch/X86_64.cpp
+++ b/lld/ELF/Arch/X86_64.cpp
@@ -328,9 +328,10 @@ bool X86_64::relaxOnce(int pass) const {
         if (rel.expr != R_RELAX_GOT_PC)
           continue;
 
-        uint64_t v = sec->getRelocTargetVA(
-            sec->file, rel.type, rel.addend,
-            sec->getOutputSection()->addr + rel.offset, *rel.sym, rel.expr);
+        uint64_t v = sec->getRelocTargetVA(sec->file, rel.type, rel.addend,
+                                           sec->getOutputSection()->addr +
+                                               sec->outSecOff + rel.offset,
+                                           *rel.sym, rel.expr);
         if (isInt<32>(v))
           continue;
         if (rel.sym->auxIdx == 0) {

diff --git a/lld/test/ELF/x86-64-gotpc-relax-too-far.s b/lld/test/ELF/x86-64-gotpc-relax-too-far.s
index 74aa6d8f65a0d8de879db4bc042868c9b3016202..ba41faab67de5c551fb65e45dbf908715008e897 100644 (file)
--- a/lld/test/ELF/x86-64-gotpc-relax-too-far.s
+++ b/lld/test/ELF/x86-64-gotpc-relax-too-far.s
@@ -5,7 +5,10 @@
 # RUN: llvm-objdump --no-print-imm-hex -d %t/bin | FileCheck --check-prefix=DISASM %s
 # RUN: llvm-readelf -S %t/bin | FileCheck --check-prefixes=GOT %s
 # RUN: ld.lld -T %t/lds2 %t/a.o -o %t/bin2
-# RUN: llvm-readelf -S %t/bin2 | FileCheck --check-prefixes=UNNECESSARY-GOT %s
+# RUN: llvm-objdump --no-print-imm-hex -d %t/bin2 | FileCheck --check-prefix=DISASM %s
+# RUN: llvm-readelf -S %t/bin2 | FileCheck --check-prefixes=GOT %s
+# RUN: ld.lld -T %t/lds3 %t/a.o -o %t/bin3
+# RUN: llvm-readelf -S %t/bin3 | FileCheck --check-prefixes=UNNECESSARY-GOT %s
 
 # DISASM:      <_foo>:
 # DISASM-NEXT: movl    2097146(%rip), %eax
@@ -47,6 +50,13 @@ SECTIONS {
   data 0x80200000 : { *(data) }
 }
 #--- lds2
+SECTIONS {
+  .text.foo 0x100000 : { *(.text.foo) }
+  .text 0x1ff000 : { . = . + 0x1000 ; *(.text) }
+  .got 0x300000 : { *(.got) }
+  data 0x80200000 : { *(data) }
+}
+#--- lds3
 SECTIONS {
   .text.foo 0x100000 : { *(.text.foo) }
   .text 0x200000 : { *(.text) }