[lld] r317427 - Move OutputSectionFactory to LinkerScript.cpp. NFC.
Rui Ueyama via llvm-commits
llvm-commits at lists.llvm.org
Sat Nov 4 16:54:25 PDT 2017
Author: ruiu
Date: Sat Nov 4 16:54:25 2017
New Revision: 317427
URL: http://llvm.org/viewvc/llvm-project?rev=317427&view=rev
Log:
Move OutputSectionFactory to LinkerScript.cpp. NFC.
That class is used only by LinkerScript.cpp, so we should move it to
that file. Also, it no longer has to be a "factory" class. It can just
be a non-member function.
Modified:
lld/trunk/ELF/LinkerScript.cpp
lld/trunk/ELF/LinkerScript.h
lld/trunk/ELF/OutputSections.cpp
lld/trunk/ELF/Writer.cpp
Modified: lld/trunk/ELF/LinkerScript.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/LinkerScript.cpp?rev=317427&r1=317426&r2=317427&view=diff
==============================================================================
--- lld/trunk/ELF/LinkerScript.cpp (original)
+++ lld/trunk/ELF/LinkerScript.cpp Sat Nov 4 16:54:25 2017
@@ -434,9 +434,107 @@ static void reportOrphan(InputSectionBas
warn(toString(IS) + " is being placed in '" + Name + "'");
}
+static OutputSection *createSection(InputSectionBase *IS,
+ StringRef OutsecName) {
+ OutputSection *Sec = Script->createOutputSection(OutsecName, "<internal>");
+ Sec->addSection(cast<InputSection>(IS));
+ return Sec;
+}
+
+static OutputSection *addInputSec(StringMap<OutputSection *> &Map,
+ InputSectionBase *IS, StringRef OutsecName) {
+ // Sections with SHT_GROUP or SHF_GROUP attributes reach here only when the -r
+ // option is given. A section with SHT_GROUP defines a "section group", and
+ // its members have SHF_GROUP attribute. Usually these flags have already been
+ // stripped by InputFiles.cpp as section groups are processed and uniquified.
+ // However, for the -r option, we want to pass through all section groups
+ // as-is because adding/removing members or merging them with other groups
+ // change their semantics.
+ if (IS->Type == SHT_GROUP || (IS->Flags & SHF_GROUP))
+ return createSection(IS, OutsecName);
+
+ // Imagine .zed : { *(.foo) *(.bar) } script. Both foo and bar may have
+ // relocation sections .rela.foo and .rela.bar for example. Most tools do
+ // not allow multiple REL[A] sections for output section. Hence we
+ // should combine these relocation sections into single output.
+ // We skip synthetic sections because it can be .rela.dyn/.rela.plt or any
+ // other REL[A] sections created by linker itself.
+ if (!isa<SyntheticSection>(IS) &&
+ (IS->Type == SHT_REL || IS->Type == SHT_RELA)) {
+ auto *Sec = cast<InputSection>(IS);
+ OutputSection *Out = Sec->getRelocatedSection()->getOutputSection();
+
+ if (Out->RelocationSection) {
+ Out->RelocationSection->addSection(Sec);
+ return nullptr;
+ }
+
+ Out->RelocationSection = createSection(IS, OutsecName);
+ return Out->RelocationSection;
+ }
+
+ // When control reaches here, mergeable sections have already been
+ // merged except the -r case. If that's the case, we do not combine them
+ // and let final link to handle this optimization.
+ if (Config->Relocatable && (IS->Flags & SHF_MERGE))
+ return createSection(IS, OutsecName);
+
+ // The ELF spec just says
+ // ----------------------------------------------------------------
+ // In the first phase, input sections that match in name, type and
+ // attribute flags should be concatenated into single sections.
+ // ----------------------------------------------------------------
+ //
+ // However, it is clear that at least some flags have to be ignored for
+ // section merging. At the very least SHF_GROUP and SHF_COMPRESSED have to be
+ // ignored. We should not have two output .text sections just because one was
+ // in a group and another was not for example.
+ //
+ // It also seems that that wording was a late addition and didn't get the
+ // necessary scrutiny.
+ //
+ // Merging sections with different flags is expected by some users. One
+ // reason is that if one file has
+ //
+ // int *const bar __attribute__((section(".foo"))) = (int *)0;
+ //
+ // gcc with -fPIC will produce a read only .foo section. But if another
+ // file has
+ //
+ // int zed;
+ // int *const bar __attribute__((section(".foo"))) = (int *)&zed;
+ //
+ // gcc with -fPIC will produce a read write section.
+ //
+ // Last but not least, when using linker script the merge rules are forced by
+ // the script. Unfortunately, linker scripts are name based. This means that
+ // expressions like *(.foo*) can refer to multiple input sections with
+ // different flags. We cannot put them in different output sections or we
+ // would produce wrong results for
+ //
+ // start = .; *(.foo.*) end = .; *(.bar)
+ //
+ // and a mapping of .foo1 and .bar1 to one section and .foo2 and .bar2 to
+ // another. The problem is that there is no way to layout those output
+ // sections such that the .foo sections are the only thing between the start
+ // and end symbols.
+ //
+ // Given the above issues, we instead merge sections by name and error on
+ // incompatible types and flags.
+ OutputSection *&Sec = Map[OutsecName];
+ if (Sec) {
+ Sec->addSection(cast<InputSection>(IS));
+ return nullptr;
+ }
+
+ Sec = createSection(IS, OutsecName);
+ return Sec;
+}
+
// Add sections that didn't match any sections command.
-void LinkerScript::addOrphanSections(OutputSectionFactory &Factory) {
+void LinkerScript::addOrphanSections() {
unsigned End = SectionCommands.size();
+ StringMap<OutputSection *> Map;
std::vector<OutputSection *> V;
for (InputSectionBase *S : InputSections) {
@@ -452,7 +550,7 @@ void LinkerScript::addOrphanSections(Out
continue;
}
- if (OutputSection *OS = Factory.addInputSec(S, Name))
+ if (OutputSection *OS = addInputSec(Map, S, Name))
V.push_back(OS);
assert(S->getOutputSection()->SectionIndex == INT_MAX);
}
Modified: lld/trunk/ELF/LinkerScript.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/LinkerScript.h?rev=317427&r1=317426&r2=317427&view=diff
==============================================================================
--- lld/trunk/ELF/LinkerScript.h (original)
+++ lld/trunk/ELF/LinkerScript.h Sat Nov 4 16:54:25 2017
@@ -251,7 +251,7 @@ public:
ExprValue getSymbolValue(StringRef Name, const Twine &Loc);
- void addOrphanSections(OutputSectionFactory &Factory);
+ void addOrphanSections();
void removeEmptyCommands();
void adjustSectionsBeforeSorting();
void adjustSectionsAfterSorting();
Modified: lld/trunk/ELF/OutputSections.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/OutputSections.cpp?rev=317427&r1=317426&r2=317427&view=diff
==============================================================================
--- lld/trunk/ELF/OutputSections.cpp (original)
+++ lld/trunk/ELF/OutputSections.cpp Sat Nov 4 16:54:25 2017
@@ -142,8 +142,6 @@ void OutputSection::addSection(InputSect
}
}
-OutputSectionFactory::OutputSectionFactory() {}
-
void elf::sortByOrder(MutableArrayRef<InputSection *> In,
std::function<int(InputSectionBase *S)> Order) {
typedef std::pair<int, InputSection *> Pair;
@@ -158,105 +156,6 @@ void elf::sortByOrder(MutableArrayRef<In
In[I] = V[I].second;
}
-static OutputSection *createSection(InputSectionBase *IS, StringRef OutsecName) {
- OutputSection *Sec = Script->createOutputSection(OutsecName, "<internal>");
- Sec->addSection(cast<InputSection>(IS));
- return Sec;
-}
-
-OutputSection *OutputSectionFactory::addInputSec(InputSectionBase *IS,
- StringRef OutsecName) {
-
- // Sections with SHT_GROUP or SHF_GROUP attributes reach here only when the -r
- // option is given. A section with SHT_GROUP defines a "section group", and
- // its members have SHF_GROUP attribute. Usually these flags have already been
- // stripped by InputFiles.cpp as section groups are processed and uniquified.
- // However, for the -r option, we want to pass through all section groups
- // as-is because adding/removing members or merging them with other groups
- // change their semantics.
- if (IS->Type == SHT_GROUP || (IS->Flags & SHF_GROUP))
- return createSection(IS, OutsecName);
-
- // Imagine .zed : { *(.foo) *(.bar) } script. Both foo and bar may have
- // relocation sections .rela.foo and .rela.bar for example. Most tools do
- // not allow multiple REL[A] sections for output section. Hence we
- // should combine these relocation sections into single output.
- // We skip synthetic sections because it can be .rela.dyn/.rela.plt or any
- // other REL[A] sections created by linker itself.
- if (!isa<SyntheticSection>(IS) &&
- (IS->Type == SHT_REL || IS->Type == SHT_RELA)) {
- auto *Sec = cast<InputSection>(IS);
- OutputSection *Out = Sec->getRelocatedSection()->getOutputSection();
-
- if (Out->RelocationSection) {
- Out->RelocationSection->addSection(Sec);
- return nullptr;
- }
-
- Out->RelocationSection = createSection(IS, OutsecName);
- return Out->RelocationSection;
- }
-
- // When control reaches here, mergeable sections have already been
- // merged except the -r case. If that's the case, we do not combine them
- // and let final link to handle this optimization.
- if (Config->Relocatable && (IS->Flags & SHF_MERGE))
- return createSection(IS, OutsecName);
-
- // The ELF spec just says
- // ----------------------------------------------------------------
- // In the first phase, input sections that match in name, type and
- // attribute flags should be concatenated into single sections.
- // ----------------------------------------------------------------
- //
- // However, it is clear that at least some flags have to be ignored for
- // section merging. At the very least SHF_GROUP and SHF_COMPRESSED have to be
- // ignored. We should not have two output .text sections just because one was
- // in a group and another was not for example.
- //
- // It also seems that that wording was a late addition and didn't get the
- // necessary scrutiny.
- //
- // Merging sections with different flags is expected by some users. One
- // reason is that if one file has
- //
- // int *const bar __attribute__((section(".foo"))) = (int *)0;
- //
- // gcc with -fPIC will produce a read only .foo section. But if another
- // file has
- //
- // int zed;
- // int *const bar __attribute__((section(".foo"))) = (int *)&zed;
- //
- // gcc with -fPIC will produce a read write section.
- //
- // Last but not least, when using linker script the merge rules are forced by
- // the script. Unfortunately, linker scripts are name based. This means that
- // expressions like *(.foo*) can refer to multiple input sections with
- // different flags. We cannot put them in different output sections or we
- // would produce wrong results for
- //
- // start = .; *(.foo.*) end = .; *(.bar)
- //
- // and a mapping of .foo1 and .bar1 to one section and .foo2 and .bar2 to
- // another. The problem is that there is no way to layout those output
- // sections such that the .foo sections are the only thing between the start
- // and end symbols.
- //
- // Given the above issues, we instead merge sections by name and error on
- // incompatible types and flags.
- OutputSection *&Sec = Map[OutsecName];
- if (Sec) {
- Sec->addSection(cast<InputSection>(IS));
- return nullptr;
- }
-
- Sec = createSection(IS, OutsecName);
- return Sec;
-}
-
-OutputSectionFactory::~OutputSectionFactory() {}
-
uint64_t elf::getHeaderSize() {
if (Config->OFormatBinary)
return 0;
Modified: lld/trunk/ELF/Writer.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Writer.cpp?rev=317427&r1=317426&r2=317427&view=diff
==============================================================================
--- lld/trunk/ELF/Writer.cpp (original)
+++ lld/trunk/ELF/Writer.cpp Sat Nov 4 16:54:25 2017
@@ -72,8 +72,6 @@ private:
std::unique_ptr<FileOutputBuffer> Buffer;
- OutputSectionFactory Factory;
-
void addRelIpltSymbols();
void addStartEndSymbols();
void addStartStopSymbols(OutputSection *Sec);
@@ -175,7 +173,7 @@ template <class ELFT> void Writer<ELFT>:
// Linker scripts controls how input sections are assigned to output sections.
// Input sections that were not handled by scripts are called "orphans", and
// they are assigned to output sections by the default rule. Process that.
- Script->addOrphanSections(Factory);
+ Script->addOrphanSections();
if (Config->Discard != DiscardPolicy::All)
copyLocalSymbols();
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