[DWARF] Refactor RelocVisitor and fix computation of SHT_RELA-typed relocation entries
Summary:
getRelocatedValue may compute incorrect value for SHT_RELA-typed relocation entries.
// DWARFDataExtractor.cpp
uint64_t DWARFDataExtractor::getRelocatedValue(uint32_t Size, uint32_t *Off,
...
// This formula is correct for REL, but may be incorrect for RELA if the value
// stored in the location (getUnsigned(Off, Size)) is not zero.
return getUnsigned(Off, Size) + Rel->Value;
In this patch, we
* refactor these visit* functions to include a new parameter `uint64_t A`.
Since these visit* functions are no longer used as visitors, rename them to resolve*.
+ REL: A is used as the addend. A is the value stored in the location where the
relocation applies: getUnsigned(Off, Size)
+ RELA: The addend encoded in RelocationRef is used, e.g. getELFAddend(R)
* and add another set of supports* functions to check if a given relocation type is handled.
DWARFObjInMemory uses them to fail early.
Reviewers: echristo, dblaikie
Reviewed By: echristo
Subscribers: mgorny, aprantl, aheejin, fedor.sergeev, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D57939
llvm-svn: 356729
diff --git a/llvm/lib/Object/RelocationResolver.cpp b/llvm/lib/Object/RelocationResolver.cpp
new file mode 100644
index 0000000..414165c
--- /dev/null
+++ b/llvm/lib/Object/RelocationResolver.cpp
@@ -0,0 +1,497 @@
+//===- RelocationResolver.cpp ------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines utilities to resolve relocations in object files.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Object/RelocationResolver.h"
+
+namespace llvm {
+namespace object {
+
+static int64_t getELFAddend(RelocationRef R) {
+ Expected<int64_t> AddendOrErr = ELFRelocationRef(R).getAddend();
+ handleAllErrors(AddendOrErr.takeError(), [](const ErrorInfoBase &EI) {
+ report_fatal_error(EI.message());
+ });
+ return *AddendOrErr;
+}
+
+static bool supportsX86_64(uint64_t Type) {
+ switch (Type) {
+ case ELF::R_X86_64_NONE:
+ case ELF::R_X86_64_64:
+ case ELF::R_X86_64_DTPOFF32:
+ case ELF::R_X86_64_DTPOFF64:
+ case ELF::R_X86_64_PC32:
+ case ELF::R_X86_64_32:
+ case ELF::R_X86_64_32S:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static uint64_t resolveX86_64(RelocationRef R, uint64_t S, uint64_t A) {
+ switch (R.getType()) {
+ case ELF::R_X86_64_NONE:
+ return A;
+ case ELF::R_X86_64_64:
+ case ELF::R_X86_64_DTPOFF32:
+ case ELF::R_X86_64_DTPOFF64:
+ return S + getELFAddend(R);
+ case ELF::R_X86_64_PC32:
+ return S + getELFAddend(R) - R.getOffset();
+ case ELF::R_X86_64_32:
+ case ELF::R_X86_64_32S:
+ return (S + getELFAddend(R)) & 0xFFFFFFFF;
+ default:
+ llvm_unreachable("Invalid relocation type");
+ }
+}
+
+static bool supportsAArch64(uint64_t Type) {
+ switch (Type) {
+ case ELF::R_AARCH64_ABS32:
+ case ELF::R_AARCH64_ABS64:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static uint64_t resolveAArch64(RelocationRef R, uint64_t S, uint64_t A) {
+ switch (R.getType()) {
+ case ELF::R_AARCH64_ABS32:
+ return (S + getELFAddend(R)) & 0xFFFFFFFF;
+ case ELF::R_AARCH64_ABS64:
+ return S + getELFAddend(R);
+ default:
+ llvm_unreachable("Invalid relocation type");
+ }
+}
+
+static bool supportsBPF(uint64_t Type) {
+ switch (Type) {
+ case ELF::R_BPF_64_32:
+ case ELF::R_BPF_64_64:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static uint64_t resolveBPF(RelocationRef R, uint64_t S, uint64_t A) {
+ switch (R.getType()) {
+ case ELF::R_BPF_64_32:
+ return S & 0xFFFFFFFF;
+ case ELF::R_BPF_64_64:
+ return S;
+ default:
+ llvm_unreachable("Invalid relocation type");
+ }
+}
+
+static bool supportsMips64(uint64_t Type) {
+ switch (Type) {
+ case ELF::R_MIPS_32:
+ case ELF::R_MIPS_64:
+ case ELF::R_MIPS_TLS_DTPREL64:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static uint64_t resolveMips64(RelocationRef R, uint64_t S, uint64_t A) {
+ switch (R.getType()) {
+ case ELF::R_MIPS_32:
+ return (S + getELFAddend(R)) & 0xFFFFFFFF;
+ case ELF::R_MIPS_64:
+ return S + getELFAddend(R);
+ case ELF::R_MIPS_TLS_DTPREL64:
+ return S + getELFAddend(R) - 0x8000;
+ default:
+ llvm_unreachable("Invalid relocation type");
+ }
+}
+
+static bool supportsPPC64(uint64_t Type) {
+ switch (Type) {
+ case ELF::R_PPC64_ADDR32:
+ case ELF::R_PPC64_ADDR64:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static uint64_t resolvePPC64(RelocationRef R, uint64_t S, uint64_t A) {
+ switch (R.getType()) {
+ case ELF::R_PPC64_ADDR32:
+ return (S + getELFAddend(R)) & 0xFFFFFFFF;
+ case ELF::R_PPC64_ADDR64:
+ return S + getELFAddend(R);
+ default:
+ llvm_unreachable("Invalid relocation type");
+ }
+}
+
+static bool supportsSystemZ(uint64_t Type) {
+ switch (Type) {
+ case ELF::R_390_32:
+ case ELF::R_390_64:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static uint64_t resolveSystemZ(RelocationRef R, uint64_t S, uint64_t A) {
+ switch (R.getType()) {
+ case ELF::R_390_32:
+ return (S + getELFAddend(R)) & 0xFFFFFFFF;
+ case ELF::R_390_64:
+ return S + getELFAddend(R);
+ default:
+ llvm_unreachable("Invalid relocation type");
+ }
+}
+
+static bool supportsSparc64(uint64_t Type) {
+ switch (Type) {
+ case ELF::R_SPARC_32:
+ case ELF::R_SPARC_64:
+ case ELF::R_SPARC_UA32:
+ case ELF::R_SPARC_UA64:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static uint64_t resolveSparc64(RelocationRef R, uint64_t S, uint64_t A) {
+ switch (R.getType()) {
+ case ELF::R_SPARC_32:
+ case ELF::R_SPARC_64:
+ case ELF::R_SPARC_UA32:
+ case ELF::R_SPARC_UA64:
+ return S + getELFAddend(R);
+ default:
+ llvm_unreachable("Invalid relocation type");
+ }
+}
+
+static bool supportsAmdgpu(uint64_t Type) {
+ switch (Type) {
+ case ELF::R_AMDGPU_ABS32:
+ case ELF::R_AMDGPU_ABS64:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static uint64_t resolveAmdgpu(RelocationRef R, uint64_t S, uint64_t A) {
+ switch (R.getType()) {
+ case ELF::R_AMDGPU_ABS32:
+ case ELF::R_AMDGPU_ABS64:
+ return S + getELFAddend(R);
+ default:
+ llvm_unreachable("Invalid relocation type");
+ }
+}
+
+static bool supportsX86(uint64_t Type) {
+ switch (Type) {
+ case ELF::R_386_NONE:
+ case ELF::R_386_32:
+ case ELF::R_386_PC32:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static uint64_t resolveX86(RelocationRef R, uint64_t S, uint64_t A) {
+ switch (R.getType()) {
+ case ELF::R_386_NONE:
+ return A;
+ case ELF::R_386_32:
+ return S + A;
+ case ELF::R_386_PC32:
+ return S - R.getOffset() + A;
+ default:
+ llvm_unreachable("Invalid relocation type");
+ }
+}
+
+static bool supportsPPC32(uint64_t Type) {
+ return Type == ELF::R_PPC_ADDR32;
+}
+
+static uint64_t resolvePPC32(RelocationRef R, uint64_t S, uint64_t A) {
+ if (R.getType() == ELF::R_PPC_ADDR32)
+ return (S + getELFAddend(R)) & 0xFFFFFFFF;
+ llvm_unreachable("Invalid relocation type");
+}
+
+static bool supportsARM(uint64_t Type) {
+ return Type == ELF::R_ARM_ABS32;
+}
+
+static uint64_t resolveARM(RelocationRef R, uint64_t S, uint64_t A) {
+ if (R.getType() == ELF::R_ARM_ABS32)
+ return (S + A) & 0xFFFFFFFF;
+ llvm_unreachable("Invalid relocation type");
+}
+
+static bool supportsAVR(uint64_t Type) {
+ switch (Type) {
+ case ELF::R_AVR_16:
+ case ELF::R_AVR_32:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static uint64_t resolveAVR(RelocationRef R, uint64_t S, uint64_t A) {
+ switch (R.getType()) {
+ case ELF::R_AVR_16:
+ return (S + getELFAddend(R)) & 0xFFFF;
+ case ELF::R_AVR_32:
+ return (S + getELFAddend(R)) & 0xFFFFFFFF;
+ default:
+ llvm_unreachable("Invalid relocation type");
+ }
+}
+
+static bool supportsLanai(uint64_t Type) {
+ return Type == ELF::R_LANAI_32;
+}
+
+static uint64_t resolveLanai(RelocationRef R, uint64_t S, uint64_t A) {
+ if (R.getType() == ELF::R_LANAI_32)
+ return (S + getELFAddend(R)) & 0xFFFFFFFF;
+ llvm_unreachable("Invalid relocation type");
+}
+
+static bool supportsMips32(uint64_t Type) {
+ switch (Type) {
+ case ELF::R_MIPS_32:
+ case ELF::R_MIPS_TLS_DTPREL32:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static uint64_t resolveMips32(RelocationRef R, uint64_t S, uint64_t A) {
+ // FIXME: Take in account implicit addends to get correct results.
+ uint32_t Rel = R.getType();
+ if (Rel == ELF::R_MIPS_32)
+ return (S + A) & 0xFFFFFFFF;
+ if (Rel == ELF::R_MIPS_TLS_DTPREL32)
+ return (S + A) & 0xFFFFFFFF;
+ llvm_unreachable("Invalid relocation type");
+}
+
+static bool supportsSparc32(uint64_t Type) {
+ switch (Type) {
+ case ELF::R_SPARC_32:
+ case ELF::R_SPARC_UA32:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static uint64_t resolveSparc32(RelocationRef R, uint64_t S, uint64_t A) {
+ uint32_t Rel = R.getType();
+ if (Rel == ELF::R_SPARC_32 || Rel == ELF::R_SPARC_UA32)
+ return S + getELFAddend(R);
+ return A;
+}
+
+static bool supportsHexagon(uint64_t Type) {
+ return Type == ELF::R_HEX_32;
+}
+
+static uint64_t resolveHexagon(RelocationRef R, uint64_t S, uint64_t A) {
+ if (R.getType() == ELF::R_HEX_32)
+ return S + getELFAddend(R);
+ llvm_unreachable("Invalid relocation type");
+}
+
+static bool supportsCOFFX86(uint64_t Type) {
+ switch (Type) {
+ case COFF::IMAGE_REL_I386_SECREL:
+ case COFF::IMAGE_REL_I386_DIR32:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static uint64_t resolveCOFFX86(RelocationRef R, uint64_t S, uint64_t A) {
+ switch (R.getType()) {
+ case COFF::IMAGE_REL_I386_SECREL:
+ case COFF::IMAGE_REL_I386_DIR32:
+ return (S + A) & 0xFFFFFFFF;
+ default:
+ llvm_unreachable("Invalid relocation type");
+ }
+}
+
+static bool supportsCOFFX86_64(uint64_t Type) {
+ switch (Type) {
+ case COFF::IMAGE_REL_AMD64_SECREL:
+ case COFF::IMAGE_REL_AMD64_ADDR64:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static uint64_t resolveCOFFX86_64(RelocationRef R, uint64_t S, uint64_t A) {
+ switch (R.getType()) {
+ case COFF::IMAGE_REL_AMD64_SECREL:
+ return (S + A) & 0xFFFFFFFF;
+ case COFF::IMAGE_REL_AMD64_ADDR64:
+ return S + A;
+ default:
+ llvm_unreachable("Invalid relocation type");
+ }
+}
+
+static bool supportsMachOX86_64(uint64_t Type) {
+ return Type == MachO::X86_64_RELOC_UNSIGNED;
+}
+
+static uint64_t resolveMachOX86_64(RelocationRef R, uint64_t S, uint64_t A) {
+ if (R.getType() == MachO::X86_64_RELOC_UNSIGNED)
+ return S;
+ llvm_unreachable("Invalid relocation type");
+}
+
+static bool supportsWasm32(uint64_t Type) {
+ switch (Type) {
+ case wasm::R_WASM_FUNCTION_INDEX_LEB:
+ case wasm::R_WASM_TABLE_INDEX_SLEB:
+ case wasm::R_WASM_TABLE_INDEX_I32:
+ case wasm::R_WASM_MEMORY_ADDR_LEB:
+ case wasm::R_WASM_MEMORY_ADDR_SLEB:
+ case wasm::R_WASM_MEMORY_ADDR_I32:
+ case wasm::R_WASM_TYPE_INDEX_LEB:
+ case wasm::R_WASM_GLOBAL_INDEX_LEB:
+ case wasm::R_WASM_FUNCTION_OFFSET_I32:
+ case wasm::R_WASM_SECTION_OFFSET_I32:
+ case wasm::R_WASM_EVENT_INDEX_LEB:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static uint64_t resolveWasm32(RelocationRef R, uint64_t S, uint64_t A) {
+ switch (R.getType()) {
+ case wasm::R_WASM_FUNCTION_INDEX_LEB:
+ case wasm::R_WASM_TABLE_INDEX_SLEB:
+ case wasm::R_WASM_TABLE_INDEX_I32:
+ case wasm::R_WASM_MEMORY_ADDR_LEB:
+ case wasm::R_WASM_MEMORY_ADDR_SLEB:
+ case wasm::R_WASM_MEMORY_ADDR_I32:
+ case wasm::R_WASM_TYPE_INDEX_LEB:
+ case wasm::R_WASM_GLOBAL_INDEX_LEB:
+ case wasm::R_WASM_FUNCTION_OFFSET_I32:
+ case wasm::R_WASM_SECTION_OFFSET_I32:
+ case wasm::R_WASM_EVENT_INDEX_LEB:
+ // For wasm section, its offset at 0 -- ignoring Value
+ return A;
+ default:
+ llvm_unreachable("Invalid relocation type");
+ }
+}
+
+std::pair<bool (*)(uint64_t), RelocationResolver>
+getRelocationResolver(const ObjectFile &Obj) {
+ if (Obj.isCOFF()) {
+ if (Obj.getBytesInAddress() == 8)
+ return {supportsCOFFX86_64, resolveCOFFX86_64};
+ return {supportsCOFFX86, resolveCOFFX86};
+ } else if (Obj.isELF()) {
+ if (Obj.getBytesInAddress() == 8) {
+ switch (Obj.getArch()) {
+ case Triple::x86_64:
+ return {supportsX86_64, resolveX86_64};
+ case Triple::aarch64:
+ case Triple::aarch64_be:
+ return {supportsAArch64, resolveAArch64};
+ case Triple::bpfel:
+ case Triple::bpfeb:
+ return {supportsBPF, resolveBPF};
+ case Triple::mips64el:
+ case Triple::mips64:
+ return {supportsMips64, resolveMips64};
+ case Triple::ppc64le:
+ case Triple::ppc64:
+ return {supportsPPC64, resolvePPC64};
+ case Triple::systemz:
+ return {supportsSystemZ, resolveSystemZ};
+ case Triple::sparcv9:
+ return {supportsSparc64, resolveSparc64};
+ case Triple::amdgcn:
+ return {supportsAmdgpu, resolveAmdgpu};
+ default:
+ return {nullptr, nullptr};
+ }
+ }
+
+ // 32-bit object file
+ assert(Obj.getBytesInAddress() == 4 &&
+ "Invalid word size in object file");
+
+ switch (Obj.getArch()) {
+ case Triple::x86:
+ return {supportsX86, resolveX86};
+ case Triple::ppc:
+ return {supportsPPC32, resolvePPC32};
+ case Triple::arm:
+ case Triple::armeb:
+ return {supportsARM, resolveARM};
+ case Triple::avr:
+ return {supportsAVR, resolveAVR};
+ case Triple::lanai:
+ return {supportsLanai, resolveLanai};
+ case Triple::mipsel:
+ case Triple::mips:
+ return {supportsMips32, resolveMips32};
+ case Triple::sparc:
+ return {supportsSparc32, resolveSparc32};
+ case Triple::hexagon:
+ return {supportsHexagon, resolveHexagon};
+ default:
+ return {nullptr, nullptr};
+ }
+ } else if (Obj.isMachO()) {
+ if (Obj.getArch() == Triple::x86_64)
+ return {supportsMachOX86_64, resolveMachOX86_64};
+ return {nullptr, nullptr};
+ } else if (Obj.isWasm()) {
+ if (Obj.getArch() == Triple::wasm32)
+ return {supportsWasm32, resolveWasm32};
+ return {nullptr, nullptr};
+ }
+
+ llvm_unreachable("Invalid object file");
+}
+
+} // namespace object
+} // namespace llvm