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[dsymutil] Skip DW_AT_sibling attributes. 

Following DW_AT_sibling attributes completely defeats the pruning pass.
Although clang doesn't generate the DW_AT_sibling attribute we should
still handle it correctly.

Differential revision: https://reviews.llvm.org/D43439

llvm-svn: 326231
This commit is contained in:
Jonas Devlieghere 2018-02-27 19:24:36 +00:00
parent 482bf0f531
commit de979bfe58
3 changed files with 22 additions and 8 deletions
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BIN
llvm/test/tools/dsymutil/Inputs/sibling.o
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25
llvm/test/tools/dsymutil/PowerPC/sibling.test
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@ -1,14 +1,27 @@
# Verify that we don't follow DW_AT_sibling references.
#
# Source:
# struct A { int a; } a;
# struct B { int b; } b;
# struct A { };
# struct B { };
#
# struct C {
# A a;
# };
#
# B b;
# C c;
#
# Compiled with Apple-GCC 4.0.1 (build 5370):
# g++ -g -c sibling.cpp -o sibling.o
# RUN: llvm-dsymutil -arch ppc -f -oso-prepend-path=%p/../Inputs/ -y %s -o - | llvm-dwarfdump -debug-info - | FileCheck %s
# CHECK: DW_TAG_variable
# CHECK-NEXT: DW_AT_name ("a")
# CHECK-NOT: DW_AT_name ("b")
# CHECK: DW_TAG_structure_type
# CHECK-NEXT: DW_AT_name ("A")
# CHECK: DW_TAG_structure_type
# CHECK-NEXT: DW_AT_name ("C")
# CHECK-NOT: DW_AT_name ("B")
---
triple: 'ppc-apple-darwin'
@ -16,5 +29,5 @@ objects:
- filename: sibling.o
timestamp: 1518197670
symbols:
- { sym: _a, objAddr: 0x00000000000000cb, binAddr: 0x0000000100000FA0, size: 0x00000010 }
- { sym: _c, objAddr: 0x000000000000017e, binAddr: 0x0000000100000FA0, size: 0x00000010 }
...

5
llvm/tools/dsymutil/DwarfLinker.cpp
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@ -2591,7 +2591,8 @@ void DwarfLinker::keepDIEAndDependencies(RelocationManager &RelocMgr,
for (const auto &AttrSpec : Abbrev->attributes()) {
DWARFFormValue Val(AttrSpec.Form);
if (!Val.isFormClass(DWARFFormValue::FC_Reference)) {
if (!Val.isFormClass(DWARFFormValue::FC_Reference) ||
AttrSpec.Attr == dwarf::DW_AT_sibling) {
DWARFFormValue::skipValue(AttrSpec.Form, Data, &Offset,
Unit.getFormParams());
continue;
@ -2767,7 +2768,7 @@ unsigned DwarfLinker::DIECloner::cloneDieReferenceAttribute(
resolveDIEReference(Linker, CompileUnits, Val, U, InputDIE, RefUnit);
// If the referenced DIE is not found, drop the attribute.
if (!RefDie)
if (!RefDie || AttrSpec.Attr == dwarf::DW_AT_sibling)
return 0;
unsigned Idx = RefUnit->getOrigUnit().getDIEIndex(RefDie);