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[BOLT] Option to control .text alignment 

Summary:
Add option `-align-text=<n>` to control .text alignment within a
segment. Set to page size by default.

(cherry picked from FBD21120063)
This commit is contained in:
Maksim Panchenko 2020-04-19 15:02:50 -07:00
parent 10245b5c5b
commit 23edb3ed9c
2 changed files with 17 additions and 6 deletions
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3
bolt/src/BinaryEmitter.cpp
View File

@ -32,6 +32,7 @@ extern cl::OptionCategory BoltCategory;
extern cl::OptionCategory BoltOptCategory;
extern cl::OptionCategory BoltRelocCategory;
extern cl::opt<unsigned> AlignText;
extern cl::opt<bool> HotText;
extern cl::opt<bool> Instrument;
extern cl::opt<JumpTableSupportLevel> JumpTables;
@ -194,7 +195,7 @@ private:
void BinaryEmitter::emitAll(StringRef OrgSecPrefix) {
Streamer.InitSections(false);
BC.getTextSection()->setAlignment(BC.PageAlign);
BC.getTextSection()->setAlignment(opts::AlignText);
emitFunctions();

20
bolt/src/RewriteInstance.cpp
View File

@ -96,6 +96,13 @@ extern cl::list<std::string> ReorderData;
extern cl::opt<bolt::ReorderFunctions::ReorderType> ReorderFunctions;
extern cl::opt<bool> TimeBuild;
cl::opt<unsigned>
AlignText("align-text",
cl::desc("alignment of .text section"),
cl::ZeroOrMore,
cl::Hidden,
cl::cat(BoltCategory));
cl::opt<bool>
Instrument("instrument",
cl::desc("instrument code to generate accurate profile data"),
@ -1669,8 +1676,7 @@ void RewriteInstance::adjustCommandLineOptions() {
opts::AlignMacroOpFusion = MFT_NONE;
}
if (opts::AlignMacroOpFusion != MFT_NONE &&
!BC->HasRelocations) {
if (opts::AlignMacroOpFusion != MFT_NONE && !BC->HasRelocations) {
outs() << "BOLT-INFO: disabling -align-macro-fusion in non-relocation "
"mode\n";
opts::AlignMacroOpFusion = MFT_NONE;
@ -1729,6 +1735,10 @@ void RewriteInstance::adjustCommandLineOptions() {
"\n";
opts::UseOldText = false;
}
if (!opts::AlignText.getNumOccurrences()) {
opts::AlignText = BC->PageAlign;
}
}
namespace {
@ -2865,12 +2875,12 @@ void RewriteInstance::mapCodeSections(orc::VModuleKey Key) {
if (CodeSize <= BC->OldTextSectionSize) {
outs() << "BOLT-INFO: using original .text for new code with 0x"
<< Twine::utohexstr(BC->PageAlign) << " alignment\n";
<< Twine::utohexstr(opts::AlignText) << " alignment\n";
AllocationDone = true;
} else {
errs() << "BOLT-WARNING: original .text too small to fit the new code"
<< " using 0x" << Twine::utohexstr(BC->PageAlign)
<< " page alignment. " << CodeSize
<< " using 0x" << Twine::utohexstr(opts::AlignText)
<< " alignment. " << CodeSize
<< " bytes needed, have " << BC->OldTextSectionSize
<< " bytes available.\n";
opts::UseOldText = false;