diff --git a/llvm/lib/MC/ELFObjectWriter.cpp b/llvm/lib/MC/ELFObjectWriter.cpp --- a/llvm/lib/MC/ELFObjectWriter.cpp +++ b/llvm/lib/MC/ELFObjectWriter.cpp @@ -1381,6 +1381,16 @@ if (TargetObjectWriter->getEMachine() == ELF::EM_386 && Type == ELF::R_386_GOTOFF) return true; + + // Work around an issue in MIPS relocation handling: both R_MIPS_HI16 and + // R_MIPS_LO16 are considered as absolute relocations (the ld.lld type is + // R_ABS). When we calculate R_MIPS_HI16's addend we find a paired + // R_MIPS_LO16, generate a combined addend and return the correct symbol + // value from the InputSectionBase::getRelocTargetVA. For R_MIPS_LO16 we + // do not do that and use its addend as is. + if (TargetObjectWriter->getEMachine() == ELF::EM_MIPS && + !hasRelocationAddend()) + return true; } // Most TLS relocations use a got, so they need the symbol. Even those that diff --git a/llvm/test/MC/Mips/mips_lo16.s b/llvm/test/MC/Mips/mips_lo16.s new file mode 100644 --- /dev/null +++ b/llvm/test/MC/Mips/mips_lo16.s @@ -0,0 +1,18 @@ +# PR49821: Check that R_MIPS_LO16 relocs do not wrap around with large addends. + +# RUN: llvm-mc %s -triple mips-unknown-unknown -filetype=obj | \ +# RUN: llvm-objdump -d -r - | FileCheck %s + + .text +foo: + lui $2, %hi(bar) +# CHECK: 0: 3c 02 00 00 lui $2, 0 +# CHECK: 00000000: R_MIPS_HI16 bar + addiu $2, $2, %lo(bar) +# CHECK: 4: 24 42 00 00 addiu $2, $2, 0 +# CHECK: 00000004: R_MIPS_LO16 bar + + .section .rodata.str1.1,"aMS",@progbits,1 + .zero 0x8000 +bar: + .asciz "hello"