diff options
| -rw-r--r-- | lld/wasm/InputChunks.cpp | 51 | ||||
| -rw-r--r-- | lld/wasm/InputChunks.h | 4 |
2 files changed, 45 insertions, 10 deletions
diff --git a/lld/wasm/InputChunks.cpp b/lld/wasm/InputChunks.cpp index 00985877434..15b1ed1f803 100644 --- a/lld/wasm/InputChunks.cpp +++ b/lld/wasm/InputChunks.cpp @@ -53,6 +53,43 @@ void InputChunk::copyRelocations(const WasmSection &Section) { Relocations.push_back(R); } +void InputChunk::verifyRelocTargets() const { + for (const WasmRelocation &Rel : Relocations) { + uint32_t ExistingValue; + unsigned BytesRead = 0; + uint32_t Offset = Rel.Offset - getInputSectionOffset(); + const uint8_t *Loc = data().data() + Offset; + switch (Rel.Type) { + case R_WEBASSEMBLY_TYPE_INDEX_LEB: + case R_WEBASSEMBLY_FUNCTION_INDEX_LEB: + case R_WEBASSEMBLY_GLOBAL_INDEX_LEB: + case R_WEBASSEMBLY_MEMORY_ADDR_LEB: + ExistingValue = decodeULEB128(Loc, &BytesRead); + break; + case R_WEBASSEMBLY_TABLE_INDEX_SLEB: + case R_WEBASSEMBLY_MEMORY_ADDR_SLEB: + ExistingValue = static_cast<uint32_t>(decodeSLEB128(Loc, &BytesRead)); + break; + case R_WEBASSEMBLY_TABLE_INDEX_I32: + case R_WEBASSEMBLY_MEMORY_ADDR_I32: + case R_WEBASSEMBLY_FUNCTION_OFFSET_I32: + case R_WEBASSEMBLY_SECTION_OFFSET_I32: + ExistingValue = static_cast<uint32_t>(read32le(Loc)); + break; + default: + llvm_unreachable("unknown relocation type"); + } + + if (BytesRead && BytesRead != 5) + warn("expected LEB at relocation site be 5-byte padded"); + uint32_t ExpectedValue = File->calcExpectedValue(Rel); + if (ExpectedValue != ExistingValue) + warn("unexpected existing value for " + ReloctTypeToString(Rel.Type) + + ": existing=" + Twine(ExistingValue) + + " expected=" + Twine(ExpectedValue)); + } +} + // Copy this input chunk to an mmap'ed output file and apply relocations. void InputChunk::writeTo(uint8_t *Buf) const { // Copy contents @@ -62,6 +99,10 @@ void InputChunk::writeTo(uint8_t *Buf) const { if (Relocations.empty()) return; +#ifndef NDEBUG + verifyRelocTargets(); +#endif + DEBUG(dbgs() << "applying relocations: " << getName() << " count=" << Relocations.size() << "\n"); int32_t Off = OutputOffset - getInputSectionOffset(); @@ -69,7 +110,6 @@ void InputChunk::writeTo(uint8_t *Buf) const { for (const WasmRelocation &Rel : Relocations) { uint8_t *Loc = Buf + Rel.Offset + Off; uint32_t Value = File->calcNewValue(Rel); - uint32_t ExistingValue; DEBUG(dbgs() << "apply reloc: type=" << ReloctTypeToString(Rel.Type) << " addend=" << Rel.Addend << " index=" << Rel.Index << " value=" << Value << " offset=" << Rel.Offset << "\n"); @@ -79,30 +119,21 @@ void InputChunk::writeTo(uint8_t *Buf) const { case R_WEBASSEMBLY_FUNCTION_INDEX_LEB: case R_WEBASSEMBLY_GLOBAL_INDEX_LEB: case R_WEBASSEMBLY_MEMORY_ADDR_LEB: - ExistingValue = decodeULEB128(Loc); encodeULEB128(Value, Loc, 5); break; case R_WEBASSEMBLY_TABLE_INDEX_SLEB: case R_WEBASSEMBLY_MEMORY_ADDR_SLEB: - ExistingValue = static_cast<uint32_t>(decodeSLEB128(Loc)); encodeSLEB128(static_cast<int32_t>(Value), Loc, 5); break; case R_WEBASSEMBLY_TABLE_INDEX_I32: case R_WEBASSEMBLY_MEMORY_ADDR_I32: case R_WEBASSEMBLY_FUNCTION_OFFSET_I32: case R_WEBASSEMBLY_SECTION_OFFSET_I32: - ExistingValue = static_cast<uint32_t>(read32le(Loc)); write32le(Loc, Value); break; default: llvm_unreachable("unknown relocation type"); } - - uint32_t ExpectedValue = File->calcExpectedValue(Rel); - if (ExpectedValue != ExistingValue) - error("unexpected existing value for " + ReloctTypeToString(Rel.Type) + - ": existing=" + Twine(ExistingValue) + - " expected=" + Twine(ExpectedValue)); } } diff --git a/lld/wasm/InputChunks.h b/lld/wasm/InputChunks.h index 4bebfbd940f..b816ff8468f 100644 --- a/lld/wasm/InputChunks.h +++ b/lld/wasm/InputChunks.h @@ -79,6 +79,10 @@ protected: virtual ArrayRef<uint8_t> data() const = 0; virtual uint32_t getInputSectionOffset() const = 0; + // Verifies the existing data at relocation targets matches our expectations. + // This is performed only debug builds as an extra sanity check. + void verifyRelocTargets() const; + std::vector<WasmRelocation> Relocations; Kind SectionKind; }; |
