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[BOLT] Fix icp-top-callsites option, remove icp-always-on. 

Summary: The icp-top-callsites option was using basic block counts to pick the top callsites while the ICP main loop was using branch info from the targets of each call.  These numbers do not exactly match up so there was a dispcrepancy in computing the top calls.  I've switch top callsites over to use the same stats as the main loop.  The icp-always-on option was redundant with -icp-top-callsites=100, so I removed it.

(cherry picked from FBD6370977)
This commit is contained in:
Bill Nell 2017-11-19 11:17:57 -08:00 committed by Maksim Panchenko
parent 591e0ef3ba
commit 0bab742949
1 changed files with 20 additions and 27 deletions
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47
bolt/Passes/IndirectCallPromotion.cpp
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@ -103,15 +103,6 @@ EliminateLoads(
cl::ZeroOrMore,
cl::cat(BoltOptCategory));
static cl::opt<bool>
ICPAlwaysOn(
"icp-always-on",
cl::desc("enable ICP for all eligible callsites"),
cl::init(false),
cl::Hidden,
cl::ZeroOrMore,
cl::cat(BoltOptCategory));
static cl::opt<unsigned>
ICPTopCallsites(
"icp-top-callsites",
@ -917,9 +908,6 @@ IndirectCallPromotion::canPromoteCallsite(const BinaryBasicBlock *BB,
}
const auto TrialN = std::min(TopN, Targets.size());
if (opts::ICPAlwaysOn)
return TrialN;
if (opts::ICPTopCallsites > 0) {
auto &BC = BB->getFunction()->getBinaryContext();
return BC.MIA->hasAnnotation(Inst, "DoICP") ? TrialN : 0;
@ -1146,7 +1134,7 @@ void IndirectCallPromotion::runOnFunctions(
// calls and then optimize the hottest callsites that contribute to that
// total.
if (opts::ICPTopCallsites > 0) {
using IndirectCallsite = std::pair<const BinaryBasicBlock *, MCInst *>;
using IndirectCallsite = std::pair<uint64_t, MCInst *>;
std::vector<IndirectCallsite> IndirectCalls;
size_t TotalIndirectCalls = 0;
@ -1166,23 +1154,28 @@ void IndirectCallPromotion::runOnFunctions(
continue;
for (auto &Inst : BB) {
if ((BC.MIA->isIndirectCall(Inst) && OptimizeCalls) ||
(Function.getJumpTable(Inst) && OptimizeJumpTables)) {
IndirectCalls.push_back(std::make_pair(&BB, &Inst));
TotalIndirectCalls += BB.getKnownExecutionCount();
const bool IsJumpTable = Function.getJumpTable(Inst);
const bool HasBranchData = BC.MIA->hasAnnotation(Inst, "Offset");
const bool IsDirectCall = (BC.MIA->isCall(Inst) &&
BC.MIA->getTargetSymbol(Inst, 0));
if (!IsDirectCall &&
((HasBranchData && !IsJumpTable && OptimizeCalls) ||
(IsJumpTable && OptimizeJumpTables))) {
uint64_t NumCalls = 0;
for (const auto &BInfo : getCallTargets(Function, Inst)) {
NumCalls += BInfo.Branches;
}
IndirectCalls.push_back(std::make_pair(NumCalls, &Inst));
TotalIndirectCalls += NumCalls;
}
}
}
}
// Sort callsites by execution count.
std::sort(IndirectCalls.begin(),
IndirectCalls.end(),
[](const IndirectCallsite &A, const IndirectCallsite &B) {
const auto CountA = A.first->getKnownExecutionCount();
const auto CountB = B.first->getKnownExecutionCount();
return CountA > CountB;
});
std::sort(IndirectCalls.rbegin(), IndirectCalls.rend());
// Find callsites that contribute to the top "opts::ICPTopCallsites"%
// number of calls.
@ -1192,7 +1185,7 @@ void IndirectCallPromotion::runOnFunctions(
for (auto &IC : IndirectCalls) {
if (MaxCalls <= 0)
break;
MaxCalls -= IC.first->getKnownExecutionCount();
MaxCalls -= IC.first;
++Num;
}
outs() << "BOLT-INFO: ICP Total indirect calls = " << TotalIndirectCalls
@ -1201,8 +1194,8 @@ void IndirectCallPromotion::runOnFunctions(
// Mark sites to optimize with "DoICP" annotation.
for (size_t I = 0; I < Num; ++I) {
auto &Inst = *IndirectCalls[I].second;
BC.MIA->addAnnotation(BC.Ctx.get(), Inst, "DoICP", true);
auto *Inst = IndirectCalls[I].second;
BC.MIA->addAnnotation(BC.Ctx.get(), *Inst, "DoICP", true);
}
}