Commit 63784b9a authored by Martin Storsjö's avatar Martin Storsjö
Browse files

[llvm-readobj] [COFF] Resolve relocations pointing at section symbols for arm64 too 

This syncs parts from the x86 implementation to the ARMWinEH
implementation.

Currently, neither of the compilers targeting COFF/arm64 (MSVC, LLVM)
produce such relocations, but LLVM might after a later patch.

Differential Revision: https://reviews.llvm.org/D109650
parent 197084fc

llvm/test/tools/llvm-readobj/COFF/arm64-unwind-preferred-symbol2.yaml

0 → 100644
+99 −0
Original line number Diff line number Diff line 
## Check that we print the external symbol "func1" and "func2", even though

## the pdata relocations point at .text with an immediate offset.



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

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



# CHECK: Function: func1 (0x0)

# CHECK: Function: func2 (0x14)



--- !COFF

header:

  Machine:         IMAGE_FILE_MACHINE_ARM64

  Characteristics: [  ]

sections:

  - Name:            .text

    Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]

    Alignment:       4

    SectionData:     FE0F1FF8E133009100000094FE0741F8C0035FD6FF8300D1F60B00F9FE0F00F9E1330091E0031FAA00000094FE0F40F9F60B40F9FF830091C0035FD6

    Relocations:

      - VirtualAddress:  8

        SymbolName:      other

        Type:            IMAGE_REL_ARM64_BRANCH26

      - VirtualAddress:  40

        SymbolName:      other

        Type:            IMAGE_REL_ARM64_BRANCH26

  - Name:            .xdata

    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ ]

    Alignment:       4

    SectionData:     0A002010D2C3D0C202E4E3E3

  - Name:            .pdata

    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ ]

    Alignment:       4

    SectionData:     000000001500A0001400000000000000

    Relocations:

      - VirtualAddress:  0

        SymbolName:      .text

        Type:            IMAGE_REL_ARM64_ADDR32NB

      - VirtualAddress:  8

        SymbolName:      .text

        Type:            IMAGE_REL_ARM64_ADDR32NB

      - VirtualAddress:  12

        SymbolName:      .xdata

        Type:            IMAGE_REL_ARM64_ADDR32NB

symbols:

  - Name:            .text

    Value:           0

    SectionNumber:   1

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_NULL

    StorageClass:    IMAGE_SYM_CLASS_STATIC

    SectionDefinition:

      Length:          60

      NumberOfRelocations: 2

      NumberOfLinenumbers: 0

      CheckSum:        2313530660

      Number:          1

  - Name:            .xdata

    Value:           0

    SectionNumber:   2

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_NULL

    StorageClass:    IMAGE_SYM_CLASS_STATIC

    SectionDefinition:

      Length:          12

      NumberOfRelocations: 0

      NumberOfLinenumbers: 0

      CheckSum:        2034129209

      Number:          2

  - Name:            .pdata

    Value:           0

    SectionNumber:   3

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_NULL

    StorageClass:    IMAGE_SYM_CLASS_STATIC

    SectionDefinition:

      Length:          16

      NumberOfRelocations: 3

      NumberOfLinenumbers: 0

      CheckSum:        3306336236

      Number:          3

  - Name:            func1

    Value:           0

    SectionNumber:   1

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_FUNCTION

    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL

  - Name:            other

    Value:           0

    SectionNumber:   0

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_NULL

    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL

  - Name:            func2

    Value:           20

    SectionNumber:   1

    SimpleType:      IMAGE_SYM_TYPE_NULL

    ComplexType:     IMAGE_SYM_DTYPE_FUNCTION

    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL

...

llvm/tools/llvm-readobj/ARMWinEHPrinter.cpp

+15 −9
Original line number Diff line number Diff line
@@ -238,22 +238,27 @@ ErrorOr<SymbolRef> Decoder::getRelocatedSymbol(const COFFObjectFile &, 
  return inconvertibleErrorCode();

}



SymbolRef Decoder::getPreferredSymbol(const COFFObjectFile &COFF,

                                      SymbolRef Sym) {

SymbolRef Decoder::getPreferredSymbol(const COFFObjectFile &COFF, SymbolRef Sym,

                                      uint64_t &SymbolOffset) {

  // The symbol resolved by getRelocatedSymbol 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)

  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()) {

      if (CS.isExternal())

        return S;

      if (CS.getStorageClass() != COFF::IMAGE_SYM_CLASS_LABEL) {

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

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

        CS.getSectionDefinition() == nullptr) {

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

      if (Offset <= SymbolOffset) {

        SymbolOffset = Offset;

        Sym = S;

        CoffSym = CS;

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

          return Sym;

      }

    }

  }
@@ -283,6 +288,9 @@ ErrorOr<SymbolRef> Decoder::getSymbolForLocation( 
    // We apply SymbolOffset here directly. We return it separately to allow

    // the caller to print it as an offset on the symbol name.

    SymbolAddress = *AddressOrErr + SymbolOffset;



    if (FunctionOnly) // Resolve label/section symbols into function names.

      SymOrErr = getPreferredSymbol(COFF, *SymOrErr, SymbolOffset);

  } else {

    // No matching relocation found; operating on a linked image. Try to

    // find a descriptive symbol if possible. The immediate offset contains
@@ -292,8 +300,6 @@ ErrorOr<SymbolRef> Decoder::getSymbolForLocation( 
    SymbolOffset = 0;

    SymOrErr = getSymbol(COFF, SymbolAddress, FunctionOnly);

  }

  if (SymOrErr && FunctionOnly) // Resolve label symbols into function names

    SymOrErr = getPreferredSymbol(COFF, *SymOrErr);

  return SymOrErr;

}

llvm/tools/llvm-readobj/ARMWinEHPrinter.h

+2 −1
Original line number Diff line number Diff line
@@ -154,7 +154,8 @@ class Decoder { 
                       bool FunctionOnly = false);



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

                                       object::SymbolRef Sym);

                                       object::SymbolRef Sym,

                                       uint64_t &SymbolOffset);



  bool dumpXDataRecord(const object::COFFObjectFile &COFF,

                       const object::SectionRef &Section,