[llvm-readobj] [COFF] Print the symbol index for relocations

There can be multiple local symbols with the same name (for e.g. comdat sections), and thus the symbol name itself isn't enough to disambiguate symbols. Differential Revision: https://reviews.llvm.org/D56140 llvm-svn: 350288
llvm · Jan 3, 2019 · 74e7d26 · 74e7d26
1 parent 5ef47ad
commit 74e7d26
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Showing 6 changed files with 26 additions and 3 deletions.
diff --git a/llvm/include/llvm/Object/COFF.h b/llvm/include/llvm/Object/COFF.h
@@ -1022,6 +1022,8 @@ class COFFObjectFile : public ObjectFile {
 
   ArrayRef<uint8_t> getSymbolAuxData(COFFSymbolRef Symbol) const;
 
+  uint32_t getSymbolIndex(COFFSymbolRef Symbol) const;
+
   size_t getSymbolTableEntrySize() const {
     if (COFFHeader)
       return sizeof(coff_symbol16);

diff --git a/llvm/lib/Object/COFFObjectFile.cpp b/llvm/lib/Object/COFFObjectFile.cpp
@@ -1065,6 +1065,16 @@ COFFObjectFile::getSymbolAuxData(COFFSymbolRef Symbol) const {
   return makeArrayRef(Aux, Symbol.getNumberOfAuxSymbols() * SymbolSize);
 }
 
+uint32_t COFFObjectFile::getSymbolIndex(COFFSymbolRef Symbol) const {
+  uintptr_t Offset =
+      reinterpret_cast<uintptr_t>(Symbol.getRawPtr()) - getSymbolTable();
+  assert(Offset % getSymbolTableEntrySize() == 0 &&
+         "Symbol did not point to the beginning of a symbol");
+  size_t Index = Offset / getSymbolTableEntrySize();
+  assert(Index < getNumberOfSymbols());
+  return Index;
+}
+
 std::error_code COFFObjectFile::getSectionName(const coff_section *Sec,
                                                StringRef &Res) const {
   StringRef Name;

diff --git a/llvm/test/MC/COFF/cross-section-relative.s b/llvm/test/MC/COFF/cross-section-relative.s
@@ -87,21 +87,25 @@ t6:
 // READOBJ-NEXT:      Offset: 0x0
 // READOBJ-NEXT:      Type: IMAGE_REL_AMD64_REL32 (4)
 // READOBJ-NEXT:      Symbol: g3
+// READOBJ-NEXT:      SymbolIndex: 12
 // READOBJ-NEXT:    }
 // READOBJ-NEXT:    Relocation {
 // READOBJ-NEXT:      Offset: 0x4
 // READOBJ-NEXT:      Type: IMAGE_REL_AMD64_ADDR32NB (3)
 // READOBJ-NEXT:      Symbol: g3
+// READOBJ-NEXT:      SymbolIndex: 12
 // READOBJ-NEXT:    }
 // READOBJ-NEXT:    Relocation {
 // READOBJ-NEXT:      Offset: 0x20
 // READOBJ-NEXT:      Type: IMAGE_REL_AMD64_REL32 (4)
 // READOBJ-NEXT:      Symbol: g3
+// READOBJ-NEXT:      SymbolIndex: 12
 // READOBJ-NEXT:    }
 // READOBJ-NEXT:    Relocation {
 // READOBJ-NEXT:      Offset: 0x28
 // READOBJ-NEXT:      Type: IMAGE_REL_AMD64_REL32 (4)
 // READOBJ-NEXT:      Symbol: foobar
+// READOBJ-NEXT:      SymbolIndex: 20
 // READOBJ-NEXT:    }
 // READOBJ-NEXT:  }
 // READOBJ-NEXT:]
diff --git a/llvm/test/Object/yaml2obj-readobj.test b/llvm/test/Object/yaml2obj-readobj.test
@@ -13,16 +13,19 @@ RUN:   | FileCheck %s --check-prefix COFF-I386
 // COFF-I386-NEXT:       Offset: 0xE
 // COFF-I386-NEXT:       Type: IMAGE_REL_I386_DIR32 (6)
 // COFF-I386-NEXT:       Symbol: L_.str
+// COFF-I386-NEXT:       SymbolIndex: 5
 // COFF-I386-NEXT:     }
 // COFF-I386-NEXT:     Relocation {
 // COFF-I386-NEXT:       Offset: 0x13
 // COFF-I386-NEXT:       Type: IMAGE_REL_I386_REL32 (20)
 // COFF-I386-NEXT:       Symbol: _puts
+// COFF-I386-NEXT:       SymbolIndex: 6
 // COFF-I386-NEXT:     }
 // COFF-I386-NEXT:     Relocation {
 // COFF-I386-NEXT:       Offset: 0x18
 // COFF-I386-NEXT:       Type: IMAGE_REL_I386_REL32 (20)
 // COFF-I386-NEXT:       Symbol: _SomeOtherFunction
+// COFF-I386-NEXT:       SymbolIndex: 7
 // COFF-I386-NEXT:     }
 // COFF-I386-NEXT:   }
 // COFF-I386-NEXT: ]
diff --git a/llvm/test/tools/llvm-readobj/relocations.test b/llvm/test/tools/llvm-readobj/relocations.test
@@ -21,9 +21,9 @@ RUN:   | FileCheck %s -check-prefix WASM
 
 COFF:      Relocations [
 COFF-NEXT:   Section (1) .text {
-COFF-NEXT:     0x4 IMAGE_REL_I386_DIR32 .data
-COFF-NEXT:     0x9 IMAGE_REL_I386_REL32 _puts
-COFF-NEXT:     0xE IMAGE_REL_I386_REL32 _SomeOtherFunction
+COFF-NEXT:     0x4 IMAGE_REL_I386_DIR32 .data (4)
+COFF-NEXT:     0x9 IMAGE_REL_I386_REL32 _puts (7)
+COFF-NEXT:     0xE IMAGE_REL_I386_REL32 _SomeOtherFunction (8)
 COFF-NEXT:   }
 COFF-NEXT: ]
 

diff --git a/llvm/tools/llvm-readobj/COFFDumper.cpp b/llvm/tools/llvm-readobj/COFFDumper.cpp
@@ -1365,22 +1365,26 @@ void COFFDumper::printRelocation(const SectionRef &Section,
   StringRef SymbolName;
   Reloc.getTypeName(RelocName);
   symbol_iterator Symbol = Reloc.getSymbol();
+  int64_t SymbolIndex = -1;
   if (Symbol != Obj->symbol_end()) {
     Expected<StringRef> SymbolNameOrErr = Symbol->getName();
     error(errorToErrorCode(SymbolNameOrErr.takeError()));
     SymbolName = *SymbolNameOrErr;
+    SymbolIndex = Obj->getSymbolIndex(Obj->getCOFFSymbol(*Symbol));
   }
 
   if (opts::ExpandRelocs) {
     DictScope Group(W, "Relocation");
     W.printHex("Offset", Offset);
     W.printNumber("Type", RelocName, RelocType);
     W.printString("Symbol", SymbolName.empty() ? "-" : SymbolName);
+    W.printNumber("SymbolIndex", SymbolIndex);
   } else {
     raw_ostream& OS = W.startLine();
     OS << W.hex(Offset)
        << " " << RelocName
        << " " << (SymbolName.empty() ? "-" : SymbolName)
+       << " (" << SymbolIndex << ")"
        << "\n";
   }
 }