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[BOLT] Fix -hot-functions-at-end option 

Summary: Make "-hot-functions-at-end" option work again.

(cherry picked from FBD14476242)
This commit is contained in:
Maksim Panchenko 2019-03-14 20:32:04 -07:00
parent 163adbec9f
commit 0a55001a0e
2 changed files with 48 additions and 27 deletions
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73
bolt/src/RewriteInstance.cpp
View File

@ -2854,6 +2854,7 @@ void RewriteInstance::emitSections() {
void RewriteInstance::emitFunctions(MCStreamer *Streamer) {
auto *TextSection = BC->MOFI->getTextSection();
TextSection->setAlignment(BC->PageAlign);
auto *ColdSection =
BC->Ctx->getELFSection(".text.cold",
ELF::SHT_PROGBITS,
@ -2960,44 +2961,64 @@ void RewriteInstance::emitFunctions(MCStreamer *Streamer) {
}
void RewriteInstance::mapFileSections(orc::VModuleKey Key) {
mapTextSections(Key);
mapCodeSections(Key);
mapDataSections(Key);
}
void RewriteInstance::mapTextSections(orc::VModuleKey Key) {
void RewriteInstance::mapCodeSections(orc::VModuleKey Key) {
if (BC->HasRelocations) {
uint64_t AllocationAddress{0};
auto TextSection = BC->getUniqueSectionByName(".text");
assert(TextSection && ".text not found in output");
auto ColdSection = BC->getUniqueSectionByName(".text.cold");
// Populate the list of sections to be allocated.
std::vector<BinarySection *> CodeSections;
for (auto &Section : BC->textSections()) {
if (Section.hasValidSectionID())
CodeSections.emplace_back(&Section);
};
DEBUG(
for (auto &Section : BC->textSections()) {
dbgs() << "code section : " << Section.getName()
<< "; valid ID : " << Section.hasValidSectionID() << '\n';
// Determine the order of sections.
std::stable_sort(CodeSections.begin(), CodeSections.end(),
[&](const BinarySection *A, const BinarySection *B) {
if (opts::HotFunctionsAtEnd) {
return B->getName() == ".text";
} else {
return A->getName() == ".text";
}
});
DEBUG(dbgs() << "Code section in the order of output:\n";
for (const auto *Section : CodeSections) {
dbgs() << Section->getName() << '\n';
});
auto CodeSize = TextSection->getOutputSize();
if (ColdSection) {
CodeSize = alignTo(CodeSize, ColdSection->getAlignment());
CodeSize += ColdSection->getOutputSize();
// Beginning address for placing code.
uint64_t AllocationAddress{0};
uint64_t CodeSize{0};
// Check if we can fit code in the original .text
if (opts::UseOldText) {
auto Code = BC->OldTextSectionAddress;
for (const auto *CodeSection : CodeSections) {
Code = alignTo(Code, CodeSection->getAlignment());
Code += CodeSection->getOutputSize();
}
CodeSize = Code - BC->OldTextSectionAddress;
if (CodeSize <= BC->OldTextSectionSize) {
outs() << "BOLT-INFO: using original .text for new code with 0x"
<< Twine::utohexstr(BC->PageAlign) << " alignment\n";
AllocationAddress = BC->OldTextSectionAddress;
}
}
auto Padding = OffsetToAlignment(BC->OldTextSectionAddress, BC->PageAlign);
if (opts::UseOldText && Padding + CodeSize <= BC->OldTextSectionSize) {
// Utilize the original .text for storage.
outs() << "BOLT-INFO: using original .text for new code with 0x"
<< Twine::utohexstr(BC->PageAlign) << " alignment\n";
AllocationAddress = BC->OldTextSectionAddress + Padding;
} else {
if (!AllocationAddress) {
if (opts::UseOldText) {
errs() << "BOLT-WARNING: original .text too small to fit the new code"
<< " using 0x" << Twine::utohexstr(BC->PageAlign)
<< " aligment. " << Padding + CodeSize
<< " page alignment. " << CodeSize
<< " bytes needed, have " << BC->OldTextSectionSize
<< " bytes available.\n";
opts::UseOldText = false;
}
AllocationAddress = alignTo(NextAvailableAddress, BC->PageAlign);
AllocationAddress = NextAvailableAddress;
}
auto mapSection = [&](BinarySection &Section) {
@ -3012,9 +3033,9 @@ void RewriteInstance::mapTextSections(orc::VModuleKey Key) {
AllocationAddress += Section.getOutputSize();
};
mapSection(*TextSection);
if (ColdSection)
mapSection(*ColdSection);
for (auto *CodeSection : CodeSections) {
mapSection(*CodeSection);
}
if (!opts::UseOldText) {
NextAvailableAddress = AllocationAddress;

2
bolt/src/RewriteInstance.h
View File

@ -121,7 +121,7 @@ public:
std::vector<const BinaryFunction *> FunctionStack);
/// Map all sections to their final addresses.
void mapTextSections(orc::VModuleKey ObjectsHandle);
void mapCodeSections(orc::VModuleKey ObjectsHandle);
void mapDataSections(orc::VModuleKey ObjectsHandle);
void mapFileSections(orc::VModuleKey ObjectsHandle);