std::error_code SampleProfileReaderGCC::readOneFunctionProfile(
const InlineCallStack &InlineStack, bool Update, uint32_t Offset) {
uint64_t HeadCount = 0;
if (InlineStack.size() == 0)
if (!GcovBuffer.readInt64(HeadCount))
return sampleprof_error::truncated;
uint32_t NameIdx;
if (!GcovBuffer.readInt(NameIdx))
return sampleprof_error::truncated;
StringRef Name(Names[NameIdx]);
uint32_t NumPosCounts;
if (!GcovBuffer.readInt(NumPosCounts))
return sampleprof_error::truncated;
uint32_t NumCallsites;
if (!GcovBuffer.readInt(NumCallsites))
return sampleprof_error::truncated;
FunctionSamples *FProfile = nullptr;
if (InlineStack.size() == 0) {
// If this is a top function that we have already processed, do not
// update its profile again. This happens in the presence of
// function aliases. Since these aliases share the same function
// body, there will be identical replicated profiles for the
// original function. In this case, we simply not bother updating
// the profile of the original function.
FProfile = &Profiles[Name];
FProfile->addHeadSamples(HeadCount);
if (FProfile->getTotalSamples() > 0)
Update = false;
} else {
// Otherwise, we are reading an inlined instance. The top of the
// inline stack contains the profile of the caller. Insert this
// callee in the caller's CallsiteMap.
FunctionSamples *CallerProfile = InlineStack.front();
uint32_t LineOffset = Offset >> 16;
uint32_t Discriminator = Offset & 0xffff;
FProfile = &CallerProfile->functionSamplesAt(
LineLocation(LineOffset, Discriminator))[Name];
}
FProfile->setName(Name);
for (uint32_t I = 0; I < NumPosCounts; ++I) {
uint32_t Offset;
if (!GcovBuffer.readInt(Offset))
return sampleprof_error::truncated;
uint32_t NumTargets;
if (!GcovBuffer.readInt(NumTargets))
return sampleprof_error::truncated;
uint64_t Count;
if (!GcovBuffer.readInt64(Count))
return sampleprof_error::truncated;
// The line location is encoded in the offset as:
// high 16 bits: line offset to the start of the function.
// low 16 bits: discriminator.
uint32_t LineOffset = Offset >> 16;
uint32_t Discriminator = Offset & 0xffff;
InlineCallStack NewStack;
NewStack.push_back(FProfile);
NewStack.insert(NewStack.end(), InlineStack.begin(), InlineStack.end());
if (Update) {
// Walk up the inline stack, adding the samples on this line to
// the total sample count of the callers in the chain.
for (auto CallerProfile : NewStack)
CallerProfile->addTotalSamples(Count);
// Update the body samples for the current profile.
FProfile->addBodySamples(LineOffset, Discriminator, Count);
}
// Process the list of functions called at an indirect call site.
// These are all the targets that a function pointer (or virtual
// function) resolved at runtime.
for (uint32_t J = 0; J < NumTargets; J++) {
uint32_t HistVal;
if (!GcovBuffer.readInt(HistVal))
return sampleprof_error::truncated;
if (HistVal != HIST_TYPE_INDIR_CALL_TOPN)
return sampleprof_error::malformed;
uint64_t TargetIdx;
if (!GcovBuffer.readInt64(TargetIdx))
return sampleprof_error::truncated;
StringRef TargetName(Names[TargetIdx]);
uint64_t TargetCount;
if (!GcovBuffer.readInt64(TargetCount))
return sampleprof_error::truncated;
if (Update)
FProfile->addCalledTargetSamples(LineOffset, Discriminator,
TargetName, TargetCount);
}
}
// Process all the inlined callers into the current function. These
// are all the callsites that were inlined into this function.
for (uint32_t I = 0; I < NumCallsites; I++) {
// The offset is encoded as:
// high 16 bits: line offset to the start of the function.
// low 16 bits: discriminator.
uint32_t Offset;
if (!GcovBuffer.readInt(Offset))
return sampleprof_error::truncated;
InlineCallStack NewStack;
NewStack.push_back(FProfile);
NewStack.insert(NewStack.end(), InlineStack.begin(), InlineStack.end());
if (std::error_code EC = readOneFunctionProfile(NewStack, Update, Offset))
return EC;
}
return sampleprof_error::success;
}
