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AArch64: diagnose out of range relocation addends on MachO. 

MachO only has 24-bit addends for most relocations, small enough that it can
overflow in semi-reasonable functions and cause insidious bugs if compiled
without assertions enabled. Switch it to an actual error instead.

The condition isn't quite identical because ld64 treats the addend as a signed
number.
This commit is contained in:
Tim Northover 2020-07-22 14:53:26 +01:00
parent 13c9bbc28e
commit 216b67e202
2 changed files with 19 additions and 1 deletions
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6
llvm/lib/Target/AArch64/MCTargetDesc/AArch64MachObjectWriter.cpp
View File

@ -373,7 +373,11 @@ void AArch64MachObjectWriter::recordRelocation(
Type == MachO::ARM64_RELOC_PAGE21 ||
Type == MachO::ARM64_RELOC_PAGEOFF12) &&
Value) {
assert((Value & 0xff000000) == 0 && "Added relocation out of range!");
if (!isInt<24>(Value)) {
Asm.getContext().reportError(Fixup.getLoc(),
"addend too big for relocation");
return;
}
MachO::any_relocation_info MRE;
MRE.r_word0 = FixupOffset;

14
llvm/test/MC/AArch64/macho-addend-range.s Normal file
View File

@ -0,0 +1,14 @@
// RUN: not llvm-mc -triple arm64-apple-ios -filetype=obj -o /dev/null %s 2>&1 | FileCheck %s
.global _foo
adrp x0, (_foo + 1)@PAGE
adrp x0, (_foo - 1)@PAGE
adrp x0, (_foo + 0x7fffff)@PAGE
adrp x0, (_foo - 0x800000)@PAGE
// CHECK-NOT: error:
// CHECK: error: addend too big for relocation
// CHECK: adrp x0, (_foo + 0x800000)@PAGE
// CHECK: error: addend too big for relocation
// CHECK: adrp x0, (_foo - 0x800001)@PAGE
adrp x0, (_foo + 0x800000)@PAGE
adrp x0, (_foo - 0x800001)@PAGE