RelExpr X86_64::adjustGotPcExpr(RelType type, int64_t addend,
const uint8_t *loc) const {
- if (type != R_X86_64_GOTPCRELX && type != R_X86_64_REX_GOTPCRELX)
+ // Only R_X86_64_[REX_]GOTPCRELX can be relaxed. GNU as may emit GOTPCRELX
+ // with addend != -4. Such an instruction does not load the full GOT entry, so
+ // we cannot relax the relocation. E.g. movl x@GOTPCREL+4(%rip), %rax
+ // (addend=0) loads the high 32 bits of the GOT entry.
+ if ((type != R_X86_64_GOTPCRELX && type != R_X86_64_REX_GOTPCRELX) ||
+ addend != -4)
return R_GOT_PC;
const uint8_t op = loc[-2];
const uint8_t modRm = loc[-1];
--- /dev/null
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64 %s -o %t.o
+# RUN: ld.lld %t.o -o %t
+# RUN: llvm-objdump -s -d %t | FileCheck %s
+
+# CHECK: Contents of section .got:
+# CHECK-NEXT: {{^}} [[#%x,ADDR:]] {{.*}} 00000000
+
+# CHECK: leal {{.*}}(%rip), %eax # {{.*}} <foo>
+# CHECK-NEXT: movl {{.*}}(%rip), %eax # [[#ADDR+4]]
+# CHECK-NEXT: movq {{.*}}(%rip), %rax # [[#ADDR+1]]
+
+## movl foo@GOTPCREL(%rip), %eax
+ movl 0(%rip), %eax
+ .reloc .-4, R_X86_64_GOTPCRELX, foo-4
+
+## The instruction has an offset (addend!=-4). It is incorrect to relax movl to leal.
+## movl foo@GOTPCREL+4(%rip), %eax
+ movl 0(%rip), %eax
+ .reloc .-4, R_X86_64_GOTPCRELX, foo
+
+## This does not make sense because it loads one byte past the GOT entry.
+## It is just to demonstrate the behavior.
+## movq foo@GOTPCREL+1(%rip), %rax
+ movq 0(%rip), %rax
+ .reloc .-4, R_X86_64_REX_GOTPCRELX, foo-3
+
+.globl foo
+foo:
+ nop