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[ThinLTO] Compute synthetic function entry count

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Summary:
This patch computes the synthetic function entry count on the whole
program callgraph (based on module summary) and writes the entry counts
to the summary. After function importing, this count gets attached to
the IR as metadata. Since it adds a new field to the summary, this bumps
up the version.

Reviewers: tejohnson

Subscribers: mehdi_amini, inglorion, llvm-commits

Differential Revision: https://reviews.llvm.org/D43521

llvm-svn: 349076
This commit is contained in:
Easwaran Raman
2018-12-13 19:54:27 +00:00
parent 41c729e78e
commit 5a7056fa03
24 changed files with 293 additions and 34 deletions
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11
llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
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@@ -3601,7 +3601,7 @@ void ModuleBitcodeWriterBase::writeModuleLevelReferences(
// Current version for the summary.
// This is bumped whenever we introduce changes in the way some record are
// interpreted, like flags for instance.
static const uint64_t INDEX_VERSION = 5;
static const uint64_t INDEX_VERSION = 6;
/// Emit the per-module summary section alongside the rest of
/// the module's bitcode.
@@ -3732,6 +3732,8 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
Flags |= 0x1;
if (Index.skipModuleByDistributedBackend())
Flags |= 0x2;
if (Index.hasSyntheticEntryCounts())
Flags |= 0x4;
Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
for (const auto &GVI : valueIds()) {
@@ -3747,6 +3749,7 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // instcount
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // fflags
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // entrycount
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // immutablerefcnt
// numrefs x valueid, n x (valueid)
@@ -3861,6 +3864,8 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
NameVals.push_back(FS->instCount());
NameVals.push_back(getEncodedFFlags(FS->fflags()));
NameVals.push_back(FS->entryCount());
// Fill in below
NameVals.push_back(0); // numrefs
NameVals.push_back(0); // immutablerefcnt
@@ -3875,8 +3880,8 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
ImmutableRefCnt++;
Count++;
}
NameVals[5] = Count;
NameVals[6] = ImmutableRefCnt;
NameVals[6] = Count;
NameVals[7] = ImmutableRefCnt;
bool HasProfileData = false;
for (auto &EI : FS->calls()) {