From 959ef1685979e96a745ac20f1b34ccd080656cb2 Mon Sep 17 00:00:00 2001 From: Rong Xu Date: Thu, 11 Apr 2019 20:54:17 +0000 Subject: [PATCH] [PGO] Better handling of profile hash mismatch We currently assume profile hash conflicts will be caught by an upfront check and we assert for the cases that escape the check. The assumption is not always true as there are chances of conflict. This patch prints a warning and skips annotating the function for the escaped cases,. Differential Revision: https://reviews.llvm.org/D60154 llvm-svn: 358225 --- .../Instrumentation/PGOInstrumentation.cpp | 26 +++-- .../Inputs/select_hash_conflict.proftext | 10 ++ .../PGOProfile/select_hash_conflict.ll | 97 +++++++++++++++++++ 3 files changed, 127 insertions(+), 6 deletions(-) create mode 100644 llvm/test/Transforms/PGOProfile/Inputs/select_hash_conflict.proftext create mode 100644 llvm/test/Transforms/PGOProfile/select_hash_conflict.ll diff --git a/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp b/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp index 99377b8a6cdc..b1c7687e19f0 100644 --- a/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp +++ b/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp @@ -1006,8 +1006,8 @@ private: // Is to use the context sensitive profile. bool IsCS; - // Find the Instrumented BB and set the value. - void setInstrumentedCounts(const std::vector &CountFromProfile); + // Find the Instrumented BB and set the value. Return false on error. + bool setInstrumentedCounts(const std::vector &CountFromProfile); // Set the edge counter value for the unknown edge -- there should be only // one unknown edge. @@ -1036,10 +1036,14 @@ private: } // end anonymous namespace // Visit all the edges and assign the count value for the instrumented -// edges and the BB. -void PGOUseFunc::setInstrumentedCounts( +// edges and the BB. Return false on error. +bool PGOUseFunc::setInstrumentedCounts( const std::vector &CountFromProfile) { - assert(FuncInfo.getNumCounters() == CountFromProfile.size()); + // The number of counters here should match the number of counters + // in profile. Return if they mismatch. + if (FuncInfo.getNumCounters() != CountFromProfile.size()) { + return false; + } // Use a worklist as we will update the vector during the iteration. std::vector WorkList; for (auto &E : FuncInfo.MST.AllEdges) @@ -1071,6 +1075,7 @@ void PGOUseFunc::setInstrumentedCounts( } ProfileCountSize = CountFromProfile.size(); CountPosition = I; + return true; } // Set the count value for the unknown edge. There should be one and only one @@ -1146,7 +1151,16 @@ bool PGOUseFunc::readCounters(IndexedInstrProfReader *PGOReader, bool &AllZeros) getBBInfo(nullptr).UnknownCountOutEdge = 2; getBBInfo(nullptr).UnknownCountInEdge = 2; - setInstrumentedCounts(CountFromProfile); + if (!setInstrumentedCounts(CountFromProfile)) { + LLVM_DEBUG( + dbgs() << "Inconsistent number of counts, skipping this function"); + Ctx.diagnose(DiagnosticInfoPGOProfile( + M->getName().data(), + Twine("Inconsistent number of counts in ") + F.getName().str() + + Twine(": the profile may be stale or there is a function name collision."), + DS_Warning)); + return false; + } ProgramMaxCount = PGOReader->getMaximumFunctionCount(IsCS); return true; } diff --git a/llvm/test/Transforms/PGOProfile/Inputs/select_hash_conflict.proftext b/llvm/test/Transforms/PGOProfile/Inputs/select_hash_conflict.proftext new file mode 100644 index 000000000000..ccc3b803fc80 --- /dev/null +++ b/llvm/test/Transforms/PGOProfile/Inputs/select_hash_conflict.proftext @@ -0,0 +1,10 @@ +# IR level Instrumentation Flag +:ir +foo +# Func Hash: +12884901887 +# Num Counters: +1 +# Counter Values: +1 + diff --git a/llvm/test/Transforms/PGOProfile/select_hash_conflict.ll b/llvm/test/Transforms/PGOProfile/select_hash_conflict.ll new file mode 100644 index 000000000000..e7c3cdb2184b --- /dev/null +++ b/llvm/test/Transforms/PGOProfile/select_hash_conflict.ll @@ -0,0 +1,97 @@ +; RUN: llvm-profdata merge %S/Inputs/select_hash_conflict.proftext -o %t.profdata +; RUN: opt < %s -pgo-instr-use -pgo-test-profile-file=%t.profdata -pgo-instr-select=true -S | FileCheck %s +; RUN: opt < %s -passes=pgo-instr-use -pgo-test-profile-file=%t.profdata -pgo-instr-select=true -S | FileCheck %s + +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-unknown-linux-gnu" + +@a = common dso_local local_unnamed_addr global [16 x i32] zeroinitializer, align 16 +@c0 = common dso_local local_unnamed_addr global i8 0, align 1 +@c1 = common dso_local local_unnamed_addr global i8 0, align 1 +@c2 = common dso_local local_unnamed_addr global i8 0, align 1 +@c3 = common dso_local local_unnamed_addr global i8 0, align 1 +@c4 = common dso_local local_unnamed_addr global i8 0, align 1 +@c5 = common dso_local local_unnamed_addr global i8 0, align 1 +@c6 = common dso_local local_unnamed_addr global i8 0, align 1 +@c7 = common dso_local local_unnamed_addr global i8 0, align 1 +@c8 = common dso_local local_unnamed_addr global i8 0, align 1 +@c9 = common dso_local local_unnamed_addr global i8 0, align 1 +@c10 = common dso_local local_unnamed_addr global i8 0, align 1 +@c11 = common dso_local local_unnamed_addr global i8 0, align 1 +@c12 = common dso_local local_unnamed_addr global i8 0, align 1 +@c13 = common dso_local local_unnamed_addr global i8 0, align 1 +@c14 = common dso_local local_unnamed_addr global i8 0, align 1 +@c15 = common dso_local local_unnamed_addr global i8 0, align 1 + +define i32 @foo(i32 %n) { +entry: + %0 = load i8, i8* @c0, align 1 + %tobool = icmp eq i8 %0, 0 + %cond = select i1 %tobool, i32 2, i32 1 + store i32 %cond, i32* getelementptr inbounds ([16 x i32], [16 x i32]* @a, i64 0, i64 0), align 16 + %1 = load i8, i8* @c1, align 1 + %tobool2 = icmp eq i8 %1, 0 + %cond3 = select i1 %tobool2, i32 2, i32 1 + store i32 %cond3, i32* getelementptr inbounds ([16 x i32], [16 x i32]* @a, i64 0, i64 1), align 4 + %2 = load i8, i8* @c2, align 1 + %tobool5 = icmp eq i8 %2, 0 + %cond6 = select i1 %tobool5, i32 2, i32 1 + store i32 %cond6, i32* getelementptr inbounds ([16 x i32], [16 x i32]* @a, i64 0, i64 2), align 8 + %3 = load i8, i8* @c3, align 1 + %tobool8 = icmp eq i8 %3, 0 + %cond9 = select i1 %tobool8, i32 2, i32 1 + store i32 %cond9, i32* getelementptr inbounds ([16 x i32], [16 x i32]* @a, i64 0, i64 3), align 4 + %4 = load i8, i8* @c4, align 1 + %tobool11 = icmp eq i8 %4, 0 + %cond12 = select i1 %tobool11, i32 2, i32 1 + store i32 %cond12, i32* getelementptr inbounds ([16 x i32], [16 x i32]* @a, i64 0, i64 4), align 16 + %5 = load i8, i8* @c5, align 1 + %tobool14 = icmp eq i8 %5, 0 + %cond15 = select i1 %tobool14, i32 2, i32 1 + store i32 %cond15, i32* getelementptr inbounds ([16 x i32], [16 x i32]* @a, i64 0, i64 5), align 4 + %6 = load i8, i8* @c6, align 1 + %tobool17 = icmp eq i8 %6, 0 + %cond18 = select i1 %tobool17, i32 2, i32 1 + store i32 %cond18, i32* getelementptr inbounds ([16 x i32], [16 x i32]* @a, i64 0, i64 6), align 8 + %7 = load i8, i8* @c7, align 1 + %tobool20 = icmp eq i8 %7, 0 + %cond21 = select i1 %tobool20, i32 2, i32 1 + store i32 %cond21, i32* getelementptr inbounds ([16 x i32], [16 x i32]* @a, i64 0, i64 7), align 4 + %8 = load i8, i8* @c8, align 1 + %tobool23 = icmp eq i8 %8, 0 + %cond24 = select i1 %tobool23, i32 2, i32 1 + store i32 %cond24, i32* getelementptr inbounds ([16 x i32], [16 x i32]* @a, i64 0, i64 8), align 16 + %9 = load i8, i8* @c9, align 1 + %tobool26 = icmp eq i8 %9, 0 + %cond27 = select i1 %tobool26, i32 2, i32 1 + store i32 %cond27, i32* getelementptr inbounds ([16 x i32], [16 x i32]* @a, i64 0, i64 9), align 4 + %10 = load i8, i8* @c10, align 1 + %tobool29 = icmp eq i8 %10, 0 + %cond30 = select i1 %tobool29, i32 2, i32 1 + store i32 %cond30, i32* getelementptr inbounds ([16 x i32], [16 x i32]* @a, i64 0, i64 10), align 8 + %11 = load i8, i8* @c11, align 1 + %tobool32 = icmp eq i8 %11, 0 + %cond33 = select i1 %tobool32, i32 2, i32 1 + store i32 %cond33, i32* getelementptr inbounds ([16 x i32], [16 x i32]* @a, i64 0, i64 11), align 4 + %12 = load i8, i8* @c12, align 1 + %tobool35 = icmp eq i8 %12, 0 + %cond36 = select i1 %tobool35, i32 2, i32 1 + store i32 %cond36, i32* getelementptr inbounds ([16 x i32], [16 x i32]* @a, i64 0, i64 12), align 16 + %13 = load i8, i8* @c13, align 1 + %tobool38 = icmp eq i8 %13, 0 + %cond39 = select i1 %tobool38, i32 2, i32 1 + store i32 %cond39, i32* getelementptr inbounds ([16 x i32], [16 x i32]* @a, i64 0, i64 13), align 4 + %14 = load i8, i8* @c14, align 1 + %tobool41 = icmp eq i8 %14, 0 + %cond42 = select i1 %tobool41, i32 2, i32 1 + store i32 %cond42, i32* getelementptr inbounds ([16 x i32], [16 x i32]* @a, i64 0, i64 14), align 8 + %15 = load i8, i8* @c15, align 1 + %tobool44 = icmp eq i8 %15, 0 + %cond45 = select i1 %tobool44, i32 2, i32 1 + store i32 %cond45, i32* getelementptr inbounds ([16 x i32], [16 x i32]* @a, i64 0, i64 15), align 4 + ret i32 %n +} +; CHECK-LABEL: define i32 @foo(i32 %n) +; We should skip the profile. +; CHECK-NOT: %{{.*}} = select i1 %{{.*}}, i32 2, i32 1, !prof +