[SampleFDO] Add profile symbol list section to discriminate function being
cold versus function being newly added.
This is the second half of https://reviews.llvm.org/D66374.
Profile symbol list is the collection of function symbols showing up in
the binary which generates the current profile. It is used to discriminate
function being cold versus function being newly added. Profile symbol list
is only added for profile with ExtBinary format.
During profile use compilation, when profile-sample-accurate is enabled,
a function without profile will be regarded as cold only when it is
contained in that list.
Differential Revision: https://reviews.llvm.org/D66766
llvm-svn: 370563
diff --git a/llvm/lib/Transforms/IPO/SampleProfile.cpp b/llvm/lib/Transforms/IPO/SampleProfile.cpp
index 224da4b..eb4ddfd 100644
--- a/llvm/lib/Transforms/IPO/SampleProfile.cpp
+++ b/llvm/lib/Transforms/IPO/SampleProfile.cpp
@@ -379,6 +379,10 @@
/// Profile Summary Info computed from sample profile.
ProfileSummaryInfo *PSI = nullptr;
+ /// Profle Symbol list tells whether a function name appears in the binary
+ /// used to generate the current profile.
+ std::unique_ptr<ProfileSymbolList> PSL;
+
/// Total number of samples collected in this profile.
///
/// This is the sum of all the samples collected in all the functions executed
@@ -1634,6 +1638,7 @@
Reader = std::move(ReaderOrErr.get());
Reader->collectFuncsToUse(M);
ProfileIsValid = (Reader->read() == sampleprof_error::success);
+ PSL = Reader->getProfileSymbolList();
if (!RemappingFilename.empty()) {
// Apply profile remappings to the loaded profile data if requested.
@@ -1725,11 +1730,15 @@
// conservatively by getEntryCount as the same as unknown (None). This is
// to avoid newly added code to be treated as cold. If we have samples
// this will be overwritten in emitAnnotations.
+ //
+ // PSL -- profile symbol list include all the symbols in sampled binary.
// If ProfileSampleAccurate is true or F has profile-sample-accurate
- // attribute, initialize the entry count to 0 so callsites or functions
- // unsampled will be treated as cold.
+ // attribute, and if there is no profile symbol list read in, initialize
+ // all the function entry counts to 0; if there is profile symbol list, only
+ // initialize the entry count to 0 when current function is in the list.
uint64_t initialEntryCount =
- (ProfileSampleAccurate || F.hasFnAttribute("profile-sample-accurate"))
+ ((ProfileSampleAccurate || F.hasFnAttribute("profile-sample-accurate")) &&
+ (!PSL || PSL->contains(F.getName())))
? 0
: -1;
F.setEntryCount(ProfileCount(initialEntryCount, Function::PCT_Real));