Commit 197084fc authored by Martin Storsjö's avatar Martin Storsjö
Browse files

[llvm-readobj] [COFF] Try to resolve symbols in unwind info on x86 

This is the same as we do on arm64 already for the MSVC style label
symbols, but also handle the way GCC produces it - with all relocations
pointing at the .text section symbol, with various offsets.

Differential Revision: https://reviews.llvm.org/D109649
parent 5b007f2c

llvm/test/tools/llvm-readobj/COFF/x86_64-unwind-preferred-symbol-gcc.yaml

0 → 100644
+118 −0
Original line number Diff line number Diff line 
## Check that we print the external symbols "func1" and "func2", even though

## the pdata relocations point at the '.text' symbol.



# RUN: yaml2obj %s -o %t.obj

# RUN: llvm-readobj --unwind %t.obj | FileCheck %s



# CHECK: StartAddress: func1

# CHECK: EndAddress: func1 +0x14

# CHECK: UnwindInfoAddress: .xdata



# CHECK: StartAddress: func2

# CHECK: EndAddress: func2 +0x16

# CHECK: UnwindInfoAddress: .xdata +0x8



--- !COFF

header:

  Machine:         IMAGE_FILE_MACHINE_AMD64

  Characteristics: [ IMAGE_FILE_LINE_NUMS_STRIPPED ]

sections:

  - Name:            .text

    Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]

    Alignment:       16

    SectionData:     4883EC38488D54242CE800000000904883C438C366662E0F1F840000000000904883EC3831C9488D54242CE800000000904883C438C3

    Relocations:

      - VirtualAddress:  10

        SymbolName:      other

        Type:            IMAGE_REL_AMD64_REL32

      - VirtualAddress:  44

        SymbolName:      other

        Type:            IMAGE_REL_AMD64_REL32

  - Name:            .xdata

    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ ]

    Alignment:       4

    SectionData:     '01040100046200000104010004620000'

  - Name:            .pdata

    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ ]

    Alignment:       4

    SectionData:     '000000001400000000000000200000003600000008000000'

    Relocations:

      - VirtualAddress:  0

        SymbolName:      .text

        Type:            IMAGE_REL_AMD64_ADDR32NB

      - VirtualAddress:  4

        SymbolName:      .text

        Type:            IMAGE_REL_AMD64_ADDR32NB

      - VirtualAddress:  8

        SymbolName:      .xdata

        Type:            IMAGE_REL_AMD64_ADDR32NB

      - VirtualAddress:  12

        SymbolName:      .text

        Type:            IMAGE_REL_AMD64_ADDR32NB

      - VirtualAddress:  16

        SymbolName:      .text

        Type:            IMAGE_REL_AMD64_ADDR32NB

      - VirtualAddress:  20

        SymbolName:      .xdata

        Type:            IMAGE_REL_AMD64_ADDR32NB

symbols:

  - Name:            func1

    Value:           0

    SectionNumber:   1

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_FUNCTION

    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL

    FunctionDefinition:

      TagIndex:        0

      TotalSize:       0

      PointerToLinenumber: 0

      PointerToNextFunction: 0

  - Name:            func2

    Value:           32

    SectionNumber:   1

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_FUNCTION

    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL

  - Name:            .text

    Value:           0

    SectionNumber:   1

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_NULL

    StorageClass:    IMAGE_SYM_CLASS_STATIC

    SectionDefinition:

      Length:          54

      NumberOfRelocations: 2

      NumberOfLinenumbers: 0

      CheckSum:        0

      Number:          0

  - Name:            .xdata

    Value:           0

    SectionNumber:   2

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_NULL

    StorageClass:    IMAGE_SYM_CLASS_STATIC

    SectionDefinition:

      Length:          16

      NumberOfRelocations: 0

      NumberOfLinenumbers: 0

      CheckSum:        0

      Number:          0

  - Name:            .pdata

    Value:           0

    SectionNumber:   3

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_NULL

    StorageClass:    IMAGE_SYM_CLASS_STATIC

    SectionDefinition:

      Length:          24

      NumberOfRelocations: 6

      NumberOfLinenumbers: 0

      CheckSum:        0

      Number:          0

  - Name:            other

    Value:           0

    SectionNumber:   0

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_FUNCTION

    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL

...

llvm/test/tools/llvm-readobj/COFF/x86_64-unwind-preferred-symbol-msvc.yaml

0 → 100644
+149 −0
Original line number Diff line number Diff line 
## Check that we print the external symbols "func1" and "func2", even though

## the pdata relocations point at the '$LN4' symbols.



# RUN: yaml2obj %s -o %t.obj

# RUN: llvm-readobj --unwind %t.obj | FileCheck %s



# CHECK: StartAddress: func1

# CHECK: EndAddress: func1 +0x13

# CHECK: UnwindInfoAddress: $unwind$func1



# CHECK: StartAddress: func2

# CHECK: EndAddress: func2 +0x15

# CHECK: UnwindInfoAddress: $unwind$func2



--- !COFF

header:

  Machine:         IMAGE_FILE_MACHINE_AMD64

  Characteristics: [  ]

sections:

  - Name:            '.text$mn'

    Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]

    Alignment:       16

    SectionData:     4883EC28488D542438E8000000004883C428C34883EC28488D54243033C9E8000000004883C428C3

    Relocations:

      - VirtualAddress:  10

        SymbolName:      other

        Type:            IMAGE_REL_AMD64_REL32

      - VirtualAddress:  44

        SymbolName:      other

        Type:            IMAGE_REL_AMD64_REL32

  - Name:            .xdata

    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ ]

    Alignment:       4

    SectionData:     '01040100044200000104010004420000'

  - Name:            .pdata

    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ ]

    Alignment:       4

    SectionData:     '000000001300000000000000000000001500000000000000'

    Relocations:

      - VirtualAddress:  0

        SymbolTableIndex: 5

        Type:            IMAGE_REL_AMD64_ADDR32NB

      - VirtualAddress:  4

        SymbolTableIndex: 5

        Type:            IMAGE_REL_AMD64_ADDR32NB

      - VirtualAddress:  8

        SymbolName:      '$unwind$func1'

        Type:            IMAGE_REL_AMD64_ADDR32NB

      - VirtualAddress:  12

        SymbolTableIndex: 6

        Type:            IMAGE_REL_AMD64_ADDR32NB

      - VirtualAddress:  16

        SymbolTableIndex: 6

        Type:            IMAGE_REL_AMD64_ADDR32NB

      - VirtualAddress:  20

        SymbolName:      '$unwind$func2'

        Type:            IMAGE_REL_AMD64_ADDR32NB

symbols:

  - Name:            '.text$mn'

    Value:           0

    SectionNumber:   1

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_NULL

    StorageClass:    IMAGE_SYM_CLASS_STATIC

    SectionDefinition:

      Length:          53

      NumberOfRelocations: 2

      NumberOfLinenumbers: 0

      CheckSum:        973622814

      Number:          0

  - Name:            other

    Value:           0

    SectionNumber:   0

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_FUNCTION

    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL

  - Name:            func1

    Value:           0

    SectionNumber:   1

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_FUNCTION

    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL

  - Name:            func2

    Value:           19

    SectionNumber:   1

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_FUNCTION

    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL

  - Name:            '$LN4'

    Value:           0

    SectionNumber:   1

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_NULL

    StorageClass:    IMAGE_SYM_CLASS_LABEL

  - Name:            '$LN4'

    Value:           19

    SectionNumber:   1

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_NULL

    StorageClass:    IMAGE_SYM_CLASS_LABEL

  - Name:            .xdata

    Value:           0

    SectionNumber:   2

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_NULL

    StorageClass:    IMAGE_SYM_CLASS_STATIC

    SectionDefinition:

      Length:          16

      NumberOfRelocations: 0

      NumberOfLinenumbers: 0

      CheckSum:        1006417668

      Number:          0

  - Name:            '$unwind$func1'

    Value:           0

    SectionNumber:   2

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_NULL

    StorageClass:    IMAGE_SYM_CLASS_STATIC

  - Name:            .pdata

    Value:           0

    SectionNumber:   3

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_NULL

    StorageClass:    IMAGE_SYM_CLASS_STATIC

    SectionDefinition:

      Length:          24

      NumberOfRelocations: 6

      NumberOfLinenumbers: 0

      CheckSum:        2067061152

      Number:          0

  - Name:            '$pdata$func1'

    Value:           0

    SectionNumber:   3

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_NULL

    StorageClass:    IMAGE_SYM_CLASS_STATIC

  - Name:            '$unwind$func2'

    Value:           8

    SectionNumber:   2

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_NULL

    StorageClass:    IMAGE_SYM_CLASS_STATIC

  - Name:            '$pdata$func2'

    Value:           12

    SectionNumber:   3

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_NULL

    StorageClass:    IMAGE_SYM_CLASS_STATIC

...

llvm/tools/llvm-readobj/Win64EHDumper.cpp

+41 −2
Original line number Diff line number Diff line
@@ -125,14 +125,52 @@ static std::error_code getSymbol(const COFFObjectFile &COFF, uint64_t VA, 
  return inconvertibleErrorCode();

}



static object::SymbolRef getPreferredSymbol(const COFFObjectFile &COFF,

                                            object::SymbolRef Sym,

                                            uint32_t &SymbolOffset,

                                            bool IsRangeEnd) {

  // The symbol resolved by ResolveSymbol can be any internal

  // nondescriptive symbol; try to resolve a more descriptive one.

  COFFSymbolRef CoffSym = COFF.getCOFFSymbol(Sym);

  if (CoffSym.getStorageClass() != COFF::IMAGE_SYM_CLASS_LABEL &&

      CoffSym.getSectionDefinition() == nullptr)

    return Sym;

  for (const auto &S : COFF.symbols()) {

    COFFSymbolRef CS = COFF.getCOFFSymbol(S);

    if (CS.getSectionNumber() == CoffSym.getSectionNumber() &&

        CS.getValue() <= CoffSym.getValue() + SymbolOffset &&

        CS.getStorageClass() != COFF::IMAGE_SYM_CLASS_LABEL &&

        CS.getSectionDefinition() == nullptr) {

      uint32_t Offset = CoffSym.getValue() + SymbolOffset - CS.getValue();

      // For the end of a range, don't pick a symbol with a zero offset;

      // prefer a symbol with a small positive offset.

      if (Offset <= SymbolOffset && (!IsRangeEnd || Offset > 0)) {

        SymbolOffset = Offset;

        Sym = S;

        CoffSym = CS;

        if (CS.isExternal() && SymbolOffset == 0)

          return Sym;

      }

    }

  }

  return Sym;

}



static std::string formatSymbol(const Dumper::Context &Ctx,

                                const coff_section *Section, uint64_t Offset,

                                uint32_t Displacement) {

                                uint32_t Displacement,

                                bool IsRangeEnd = false) {

  std::string Buffer;

  raw_string_ostream OS(Buffer);



  SymbolRef Symbol;

  if (!Ctx.ResolveSymbol(Section, Offset, Symbol, Ctx.UserData)) {

    // We found a relocation at the given offset in the section, pointing

    // at a symbol.



    // Try to resolve label/section symbols into function names.

    Symbol = getPreferredSymbol(Ctx.COFF, Symbol, Displacement, IsRangeEnd);



    Expected<StringRef> Name = Symbol.getName();

    if (Name) {

      OS << *Name;
@@ -207,7 +245,8 @@ void Dumper::printRuntimeFunctionEntry(const Context &Ctx, 
  SW.printString("StartAddress",

                 formatSymbol(Ctx, Section, Offset + 0, RF.StartAddress));

  SW.printString("EndAddress",

                 formatSymbol(Ctx, Section, Offset + 4, RF.EndAddress));

                 formatSymbol(Ctx, Section, Offset + 4, RF.EndAddress,

                              /*IsRangeEnd=*/true));

  SW.printString("UnwindInfoAddress",

                 formatSymbol(Ctx, Section, Offset + 8, RF.UnwindInfoOffset));

}