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Add a flag to InputSectionBase for linker script. 

Previously, we set (uintptr_t)-1 to InputSectionBase::OutSec to record
that a section has already been set to be assigned to some output section
by linker scripts. Later, we restored nullptr to the pointer to use
the field for the original purpose. That overloading is not very easy to
understand.

This patch adds a bit flag for that purpose, so that we don't need
to piggyback the flag on an unrelated pointer.

llvm-svn: 287508
This commit is contained in:
Rui Ueyama 2016-11-20 23:15:52 +00:00
parent a228c46c2a
commit f94efdddc0
2 changed files with 10 additions and 20 deletions
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9
lld/ELF/InputSection.h
View File

@ -45,8 +45,8 @@ public:
// If GC is disabled, all sections are considered live by default.
InputSectionData(Kind SectionKind, StringRef Name, ArrayRef<uint8_t> Data,
bool Compressed, bool Live)
: SectionKind(SectionKind), Live(Live), Compressed(Compressed),
Name(Name), Data(Data) {}
: SectionKind(SectionKind), Live(Live), Assigned(false),
Compressed(Compressed), Name(Name), Data(Data) {}
private:
unsigned SectionKind : 3;
@ -54,8 +54,9 @@ private:
public:
Kind kind() const { return (Kind)SectionKind; }
unsigned Live : 1; // for garbage collection
unsigned Compressed : 1;
unsigned Live : 1; // for garbage collection
unsigned Assigned : 1; // for linker script
unsigned Compressed : 1; // true if section data is compressed
uint32_t Alignment;
StringRef Name;
ArrayRef<uint8_t> Data;

21
lld/ELF/LinkerScript.cpp
View File

@ -199,7 +199,7 @@ void LinkerScript<ELFT>::computeInputSections(InputSectionDescription *I) {
size_t SizeBefore = I->Sections.size();
for (InputSectionBase<ELFT> *S : Symtab<ELFT>::X->Sections) {
if (!S->Live || S->OutSec)
if (!S->Live || S->Assigned)
continue;
StringRef Filename;
@ -207,8 +207,10 @@ void LinkerScript<ELFT>::computeInputSections(InputSectionDescription *I) {
Filename = sys::path::filename(F->getName());
if (I->FilePat.match(Filename) && !Pat.ExcludedFilePat.match(Filename) &&
Pat.SectionPat.match(S->Name))
Pat.SectionPat.match(S->Name)) {
I->Sections.push_back(S);
S->Assigned = true;
}
}
// Sort sections as instructed by SORT-family commands and --sort-section
@ -232,13 +234,6 @@ void LinkerScript<ELFT>::computeInputSections(InputSectionDescription *I) {
sortSections(Begin, End, Pat.SortOuter);
}
}
// We do not add duplicate input sections, so mark them with a dummy output
// section for now.
for (InputSectionData *S : I->Sections) {
auto *S2 = static_cast<InputSectionBase<ELFT> *>(S);
S2->OutSec = (OutputSectionBase *)-1;
}
}
template <class ELFT>
@ -263,12 +258,6 @@ LinkerScript<ELFT>::createInputSectionList(OutputSectionCommand &OutCmd) {
Ret.push_back(static_cast<InputSectionBase<ELFT> *>(S));
}
// After we created final list we should now set OutSec pointer to null,
// instead of -1. Otherwise we may get a crash when writing relocs, in
// case section is discarded by linker script
for (InputSectionBase<ELFT> *S : Ret)
S->OutSec = nullptr;
return Ret;
}
@ -343,7 +332,7 @@ void LinkerScript<ELFT>::processCommands(OutputSectionFactory<ELFT> &Factory) {
if (!matchConstraints<ELFT>(V, Cmd->Constraint)) {
for (InputSectionBase<ELFT> *S : V)
S->OutSec = nullptr;
S->Assigned = false;
Opt.Commands.erase(Iter);
--I;
continue;