[ELF] Error for out-of-range R_X86_64_[REX_]GOTPCRELX

[grimar]

LGTM

lld/test/ELF/x86-64-gotpc-err.s

9

I'd perhaps use --implicit-check-not=error: instead. It feels a bit safer because doesn't depend on the order.
Though I don't really think that the order of this error messages might change too.

[jhenderson]

Looks good to me aside from @grimar's comment.

lld/test/ELF/x86-64-gotpc-err.s

9

I guess in theory something else could cause an error before or between the two existing errors. Do we really care though?

[MaskRay]

lld/test/ELF/x86-64-gotpc-err.s

9

That's too unlikely. I'll stick with the current version.

lld/ELF/Arch/X86_64.cpp

static void relaxGotNoPic(uint8_t *loc, uint64_t val, uint8_t op,
   // See "3.2 INSTRUCTIONS (A-M)" (Vol. 2A 3-15),
   // "INSTRUCTION SET REFERENCE, N-Z" (Vol. 2B 4-1) for
   // descriptions about each operation.
   loc[-2] = 0x81;
   loc[-3] = (rex & ~0x4) | (rex & 0x4) >> 2;
   write32le(loc, val);
 }
 
-void X86_64::relaxGot(uint8_t *loc, const Relocation &, uint64_t val) const {
+void X86_64::relaxGot(uint8_t *loc, const Relocation &rel, uint64_t val) const {
+  checkInt(loc, val, 32, rel);
   const uint8_t op = loc[-2];
   const uint8_t modRm = loc[-1];
 
   // Convert "mov foo@GOTPCREL(%rip),%reg" to "lea foo(%rip),%reg".
   if (op == 0x8b) {
     loc[-2] = 0x8d;
     write32le(loc, val);
     return;

lld/test/ELF/x86-64-gotpc-err.s

+# REQUIRES: x86
+# RUN: split-file %s %t
+# RUN: llvm-mc -filetype=obj -triple=x86_64 %t/a.s -o %t/a.o
+# RUN: not ld.lld -T %t/lds %t/a.o -o /dev/null 2>&1 | FileCheck %s
+
+# CHECK:     error: {{.*}}:(.text+0x2): relocation R_X86_64_GOTPCRELX out of range: 2147483655 is not in [-2147483648, 2147483647]; references data
+# CHECK:     error: {{.*}}:(.text+0x9): relocation R_X86_64_REX_GOTPCRELX out of range: 2147483648 is not in [-2147483648, 2147483647]; references data
+# CHECK-NOT: error:
+
+#--- a.s
+  movl data@GOTPCREL(%rip), %eax  # out of range
+  movq data@GOTPCREL(%rip), %rax  # out of range
+  movq data@GOTPCREL(%rip), %rax  # in range
+
+.data
+.space 13
+.globl data
+data:
+  .long 0
+
+#--- lds
+SECTIONS {
+  .text 0x200000 : { *(.text) }
+  .data 0x80200000 : { *(.data) }
+}