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[dsymutil] Fix handling of cross-cu forward references. 

We recorded the forward references in the CU that holds the referenced
DIE, but this is wrong as those will get resoled *after* the CU that
holds the reference. Record the references in their originating CU along
with a pointer to the remote CU to be able to compute the fixed up
offset at the right time.

llvm-svn: 232193
This commit is contained in:
Frederic Riss 2015-03-13 18:35:57 +00:00
parent 5a62dc3793
commit 6afcfce2d9
2 changed files with 35 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
llvm/test/tools/dsymutil/X86/basic-lto-dw4-linking-x86.test
View File

@ -5,7 +5,6 @@ CHECK: file format Mach-O 64-bit x86-64
CHECK: debug_info contents
CHECK: Compile Unit: {{.*}} version = 0x0004
CHECK: DW_TAG_compile_unit [1] *
CHECK: DW_AT_producer [DW_FORM_strp] ( .debug_str[0x00000001] = "clang version 3.7.0 ")
CHECK: DW_AT_language [DW_FORM_data2] (DW_LANG_C99)
@ -19,15 +18,19 @@ CHECK: DW_AT_high_pc [DW_FORM_data4] (0x0000000b)
CHECK: DW_AT_frame_base [DW_FORM_exprloc] (<0x1> 56 )
CHECK: DW_AT_name [DW_FORM_strp] ( .debug_str[0x00000027] = "main")
CHECK: DW_AT_prototyped [DW_FORM_flag_present] (true)
CHECK: DW_AT_type [DW_FORM_ref_addr] (0x00000000000000a1)
CHECK: DW_AT_external [DW_FORM_flag_present] (true)
CHECK: DW_TAG_formal_parameter [3]
CHECK: DW_AT_location [DW_FORM_exprloc] (<0x3> 55 93 04 )
CHECK: DW_AT_name [DW_FORM_strp] ( .debug_str[0x0000002c] = "argc")
CHECK: DW_AT_type [DW_FORM_ref_addr] (0x00000000000000a1)
CHECK: DW_TAG_formal_parameter [4]
CHECK: DW_AT_location [DW_FORM_exprloc] (<0x1> 54 )
CHECK: DW_AT_name [DW_FORM_strp] ( .debug_str[0x00000031] = "argv")
CHECK: DW_AT_type [DW_FORM_ref4] (cu + 0x0060 => {0x00000060})
CHECK: NULL
CHECK: DW_TAG_pointer_type [5]
CHECK: DW_AT_type [DW_FORM_ref4] (cu + 0x0065 => {0x00000065})
CHECK: DW_TAG_pointer_type [5]
CHECK: DW_TAG_const_type [6]
CHECK: DW_TAG_base_type [7]

50
llvm/tools/dsymutil/DwarfLinker.cpp
View File

@ -33,6 +33,7 @@
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include <string>
#include <tuple>
namespace llvm {
namespace dsymutil {
@ -70,8 +71,8 @@ public:
};
CompileUnit(DWARFUnit &OrigUnit)
: OrigUnit(OrigUnit), LowPc(UINT64_MAX), HighPc(0), RangeAlloc(),
Ranges(RangeAlloc) {
: OrigUnit(OrigUnit), LowPc(UINT64_MAX), HighPc(0), RangeAlloc(),
Ranges(RangeAlloc) {
Info.resize(OrigUnit.getNumDIEs());
}
@ -106,10 +107,11 @@ public:
/// debug_info section size).
uint64_t computeNextUnitOffset();
/// \brief Keep track of a forward reference to DIE \p Die by
/// \p Attr. The attribute should be fixed up later to point to the
/// absolute offset of \p Die in the debug_info section.
void noteForwardReference(DIE *Die, DIEInteger *Attr);
/// \brief Keep track of a forward reference to DIE \p Die in \p
/// RefUnit by \p Attr. The attribute should be fixed up later to
/// point to the absolute offset of \p Die in the debug_info section.
void noteForwardReference(DIE *Die, const CompileUnit *RefUnit,
DIEInteger *Attr);
/// \brief Apply all fixups recored by noteForwardReference().
void fixupForwardReferences();
@ -133,9 +135,10 @@ private:
/// a DIE in the debug_info section.
///
/// The offsets for the attributes in this array couldn't be set while
/// cloning because for forward refences the target DIE's offset isn't
/// known you emit the reference attribute.
std::vector<std::pair<DIE *, DIEInteger *>> ForwardDIEReferences;
/// cloning because for cross-cu forward refences the target DIE's
/// offset isn't known you emit the reference attribute.
std::vector<std::tuple<DIE *, const CompileUnit *, DIEInteger *>>
ForwardDIEReferences;
HalfOpenIntervalMap<uint64_t, int64_t>::Allocator RangeAlloc;
/// \brief The ranges in that interval map are the PC ranges for
@ -154,15 +157,22 @@ uint64_t CompileUnit::computeNextUnitOffset() {
return NextUnitOffset;
}
/// \brief Keep track of a forward reference to \p Die.
void CompileUnit::noteForwardReference(DIE *Die, DIEInteger *Attr) {
ForwardDIEReferences.emplace_back(Die, Attr);
/// \brief Keep track of a forward cross-cu reference from this unit
/// to \p Die that lives in \p RefUnit.
void CompileUnit::noteForwardReference(DIE *Die, const CompileUnit *RefUnit,
DIEInteger *Attr) {
ForwardDIEReferences.emplace_back(Die, RefUnit, Attr);
}
/// \brief Apply all fixups recorded by noteForwardReference().
void CompileUnit::fixupForwardReferences() {
for (const auto &Ref : ForwardDIEReferences)
Ref.second->setValue(Ref.first->getOffset() + getStartOffset());
for (const auto &Ref : ForwardDIEReferences) {
DIE *RefDie;
const CompileUnit *RefUnit;
DIEInteger *Attr;
std::tie(RefDie, RefUnit, Attr) = Ref;
Attr->setValue(RefDie->getOffset() + RefUnit->getStartOffset());
}
}
void CompileUnit::addFunctionRange(uint64_t FuncLowPc, uint64_t FuncHighPc,
@ -598,7 +608,7 @@ private:
cloneDieReferenceAttribute(DIE &Die,
const DWARFDebugInfoEntryMinimal &InputDIE,
AttributeSpec AttrSpec, unsigned AttrSize,
const DWARFFormValue &Val, const DWARFUnit &U);
const DWARFFormValue &Val, CompileUnit &Unit);
/// \brief Helper for cloneDIE.
unsigned cloneBlockAttribute(DIE &Die, AttributeSpec AttrSpec,
@ -1169,8 +1179,8 @@ unsigned DwarfLinker::cloneStringAttribute(DIE &Die, AttributeSpec AttrSpec,
unsigned DwarfLinker::cloneDieReferenceAttribute(
DIE &Die, const DWARFDebugInfoEntryMinimal &InputDIE,
AttributeSpec AttrSpec, unsigned AttrSize, const DWARFFormValue &Val,
const DWARFUnit &U) {
uint32_t Ref = *Val.getAsReference(&U);
CompileUnit &Unit) {
uint32_t Ref = *Val.getAsReference(&Unit.getOrigUnit());
DIE *NewRefDie = nullptr;
CompileUnit *RefUnit = nullptr;
const DWARFDebugInfoEntryMinimal *RefDie = nullptr;
@ -1182,7 +1192,7 @@ unsigned DwarfLinker::cloneDieReferenceAttribute(
AttributeString = "DW_AT_???";
reportWarning(Twine("Missing DIE for ref in attribute ") + AttributeString +
". Dropping.",
&U, &InputDIE);
&Unit.getOrigUnit(), &InputDIE);
return 0;
}
@ -1211,7 +1221,7 @@ unsigned DwarfLinker::cloneDieReferenceAttribute(
} else {
// A forward reference. Note and fixup later.
Attr = new (DIEAlloc) DIEInteger(0xBADDEF);
RefUnit->noteForwardReference(NewRefDie, Attr);
Unit.noteForwardReference(NewRefDie, RefUnit, Attr);
}
Die.addValue(dwarf::Attribute(AttrSpec.Attr), dwarf::DW_FORM_ref_addr,
Attr);
@ -1346,7 +1356,7 @@ unsigned DwarfLinker::cloneAttribute(DIE &Die,
case dwarf::DW_FORM_ref4:
case dwarf::DW_FORM_ref8:
return cloneDieReferenceAttribute(Die, InputDIE, AttrSpec, AttrSize, Val,
U);
Unit);
case dwarf::DW_FORM_block:
case dwarf::DW_FORM_block1:
case dwarf::DW_FORM_block2: