diff options
Diffstat (limited to 'contrib/llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUAsmBackend.cpp')
| -rw-r--r-- | contrib/llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUAsmBackend.cpp | 27 |
1 files changed, 17 insertions, 10 deletions
diff --git a/contrib/llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUAsmBackend.cpp b/contrib/llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUAsmBackend.cpp index 4434d9b..60e8c8f 100644 --- a/contrib/llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUAsmBackend.cpp +++ b/contrib/llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUAsmBackend.cpp @@ -99,14 +99,22 @@ void AMDGPUAsmBackend::applyFixup(const MCFixup &Fixup, char *Data, case AMDGPU::fixup_si_rodata: { uint32_t *Dst = (uint32_t*)(Data + Fixup.getOffset()); - *Dst = Value; - break; - } - - case AMDGPU::fixup_si_end_of_text: { - uint32_t *Dst = (uint32_t*)(Data + Fixup.getOffset()); - // The value points to the last instruction in the text section, so we - // need to add 4 bytes to get to the start of the constants. + // We emit constant data at the end of the text section and generate its + // address using the following code sequence: + // s_getpc_b64 s[0:1] + // s_add_u32 s0, s0, $symbol + // s_addc_u32 s1, s1, 0 + // + // s_getpc_b64 returns the address of the s_add_u32 instruction and then + // the fixup replaces $symbol with a literal constant, which is a + // pc-relative offset from the encoding of the $symbol operand to the + // constant data. + // + // What we want here is an offset from the start of the s_add_u32 + // instruction to the constant data, but since the encoding of $symbol + // starts 4 bytes after the start of the add instruction, we end up + // with an offset that is 4 bytes too small. This requires us to + // add 4 to the fixup value before applying it. *Dst = Value + 4; break; } @@ -136,8 +144,7 @@ const MCFixupKindInfo &AMDGPUAsmBackend::getFixupKindInfo( const static MCFixupKindInfo Infos[AMDGPU::NumTargetFixupKinds] = { // name offset bits flags { "fixup_si_sopp_br", 0, 16, MCFixupKindInfo::FKF_IsPCRel }, - { "fixup_si_rodata", 0, 32, 0 }, - { "fixup_si_end_of_text", 0, 32, MCFixupKindInfo::FKF_IsPCRel } + { "fixup_si_rodata", 0, 32, MCFixupKindInfo::FKF_IsPCRel } }; if (Kind < FirstTargetFixupKind) |
