Commit 02b6a3c3 authored by David Stenberg's avatar David Stenberg
Browse files

[DebugInfo] Handle generic type DW_OP_convert ops in dsymutil 

Summary:
This is a preparatory change for allowing LLVM to emit DW_OP_convert
operations converting to the generic type.

If DW_OP_convert's operand is 0, it converts the top of the stack to the
generic type, as specified by DWARFv5 section 2.5.1.6:

"[...] takes one operand, which is an unsigned LEB128 integer that
 represents the offset of a debugging information entry in the current
 compilation unit, or value 0 which represents the generic type."

This adds support for such operations to dsymutil.

Reviewers: aprantl, markus, friss, JDevlieghere

Reviewed By: aprantl, JDevlieghere

Subscribers: hiraditya, llvm-commits

Tags: #debug-info, #llvm

Differential Revision: https://reviews.llvm.org/D76142
parent 5abfa322

llvm/lib/DWARFLinker/DWARFLinker.cpp

+13 −8
Original line number Diff line number Diff line
@@ -923,15 +923,20 @@ void DWARFLinker::DIECloner::cloneExpression( 
        OutputBuffer.push_back(Op.getRawOperand(0));

        RefOffset = Op.getRawOperand(1);

      }

      uint32_t Offset = 0;

      // Look up the base type. For DW_OP_convert, the operand may be 0 to

      // instead indicate the generic type. The same holds for

      // DW_OP_reinterpret, which is currently not supported.

      if (RefOffset > 0 || Op.getCode() != dwarf::DW_OP_convert) {

        auto RefDie = Unit.getOrigUnit().getDIEForOffset(RefOffset);

        uint32_t RefIdx = Unit.getOrigUnit().getDIEIndex(RefDie);

        CompileUnit::DIEInfo &Info = Unit.getInfo(RefIdx);

      uint32_t Offset = 0;

        if (DIE *Clone = Info.Clone)

          Offset = Clone->getOffset();

        else

        Linker.reportWarning("base type ref doesn't point to DW_TAG_base_type.",

                             File);

          Linker.reportWarning(

              "base type ref doesn't point to DW_TAG_base_type.", File);

      }

      uint8_t ULEB[16];

      unsigned RealSize = encodeULEB128(Offset, ULEB, ULEBsize);

      if (RealSize > ULEBsize) {

llvm/test/tools/dsymutil/Inputs/op-convert.ll

+2 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ entry: 
  call void @llvm.dbg.value(metadata i8 42, metadata !17, metadata !DIExpression(DW_OP_LLVM_convert, 32, DW_ATE_signed, DW_OP_stack_value)), !dbg !12

  call void @llvm.dbg.value(metadata i8 %x, metadata !11, metadata !DIExpression()), !dbg !12

  call void @llvm.dbg.value(metadata i8 %x, metadata !13, metadata !DIExpression(DW_OP_LLVM_convert, 8, DW_ATE_signed, DW_OP_LLVM_convert, 32, DW_ATE_signed, DW_OP_stack_value)), !dbg !15

  call void @llvm.dbg.value(metadata i8 51, metadata !18, metadata !DIExpression(DW_OP_LLVM_convert_generic, DW_OP_stack_value)), !dbg !15

  ret i8 %x, !dbg !16

}
@@ -43,3 +44,4 @@ attributes #1 = { nounwind readnone speculatable } 
!15 = !DILocation(line: 3, column: 14, scope: !7)

!16 = !DILocation(line: 4, column: 3, scope: !7)

!17 = !DILocalVariable(name: "c", scope: !7, file: !1, line: 3, type: !14)

!18 = !DILocalVariable(name: "d", scope: !7, file: !1, line: 3, type: !14)

llvm/test/tools/dsymutil/X86/op-convert.test

+4 −0
Original line number Diff line number Diff line
@@ -26,6 +26,10 @@ CHECK-NEXT: [0x0000000000001000, 0x0000000000001002): DW_OP_breg5 RDI+0, DW 
CHECK-NEXT:     [0x0000000000001002,  0x0000000000001003): DW_OP_breg0 RAX+0, DW_OP_constu 0xffffffff, DW_OP_and, DW_OP_convert (0x0000002a) "DW_ATE_signed_8", DW_OP_convert (0x00000031) "DW_ATE_signed_32", DW_OP_stack_value)

CHECK-NEXT:     DW_AT_name	("y")



CHECK:     DW_TAG_variable

CHECK-NEXT:     DW_AT_location	(DW_OP_constu 0x33, DW_OP_convert 0x0, DW_OP_stack_value)

CHECK-NEXT:     DW_AT_name	("d")



CHECK:     DW_TAG_variable

CHECK-NEXT:     DW_AT_location	(DW_OP_constu 0x2a, DW_OP_convert (0x00000031) "DW_ATE_signed_32", DW_OP_stack_value)

CHECK-NEXT:     DW_AT_name	("c")