[llvm-objcopy] - Fix --compress-debug-sections when there are relocations.
When --compress-debug-sections is given,
llvm-objcopy removes the uncompressed sections and adds compressed to the section list.
This makes all the pointers to old sections to be outdated.
Currently, code already has logic for replacing the target sections of the relocation
sections. But we also have to update the relocations by themselves.
This fixes https://bugs.llvm.org/show_bug.cgi?id=40885.
Differential revision: https://reviews.llvm.org/D58960
llvm-svn: 355821
diff --git a/llvm/tools/llvm-objcopy/ELF/ELFObjcopy.cpp b/llvm/tools/llvm-objcopy/ELF/ELFObjcopy.cpp
index 6f21db9..83f1f0e 100644
--- a/llvm/tools/llvm-objcopy/ELF/ELFObjcopy.cpp
+++ b/llvm/tools/llvm-objcopy/ELF/ELFObjcopy.cpp
@@ -232,27 +232,24 @@
const CopyConfig &Config, Object &Obj, SectionPred &RemovePred,
function_ref<bool(const SectionBase &)> shouldReplace,
function_ref<SectionBase *(const SectionBase *)> addSection) {
+ // Build a list of the debug sections we are going to replace.
+ // We can't call `addSection` while iterating over sections,
+ // because it would mutate the sections array.
SmallVector<SectionBase *, 13> ToReplace;
- SmallVector<RelocationSection *, 13> RelocationSections;
- for (auto &Sec : Obj.sections()) {
- if (RelocationSection *R = dyn_cast<RelocationSection>(&Sec)) {
- if (shouldReplace(*R->getSection()))
- RelocationSections.push_back(R);
- continue;
- }
-
+ for (auto &Sec : Obj.sections())
if (shouldReplace(Sec))
ToReplace.push_back(&Sec);
- }
- for (SectionBase *S : ToReplace) {
- SectionBase *NewSection = addSection(S);
+ // Build a mapping from original section to a new one.
+ DenseMap<SectionBase *, SectionBase *> FromTo;
+ for (SectionBase *S : ToReplace)
+ FromTo[S] = addSection(S);
- for (RelocationSection *RS : RelocationSections) {
- if (RS->getSection() == S)
- RS->setSection(NewSection);
- }
- }
+ // Now we want to update the target sections of relocation
+ // sections. Also we will update the relocations themselves
+ // to update the symbol references.
+ for (auto &Sec : Obj.sections())
+ Sec.replaceSectionReferences(FromTo);
RemovePred = [shouldReplace, RemovePred](const SectionBase &Sec) {
return shouldReplace(Sec) || RemovePred(Sec);