r206081 - CodeGen: Fix handling of C++11 lambdas in profiling

Richard Smith richard at metafoo.co.uk
Sat Apr 12 16:08:56 PDT 2014


Should we do the same for CapturedStmt?
On 11 Apr 2014 16:14, "Justin Bogner" <mail at justinbogner.com> wrote:

> Author: bogner
> Date: Fri Apr 11 18:06:35 2014
> New Revision: 206081
>
> URL: http://llvm.org/viewvc/llvm-project?rev=206081&view=rev
> Log:
> CodeGen: Fix handling of C++11 lambdas in profiling
>
> Until now we were generating duplicate counters for lambdas: one set
> in the function where the lambda was declared and another for the
> lambda itself. Instead, we should skip over the bodies of lambdas in
> their containing contexts.
>
> Added:
>     cfe/trunk/test/Profile/Inputs/cxx-lambda.profdata
>     cfe/trunk/test/Profile/cxx-lambda.cpp
> Modified:
>     cfe/trunk/lib/CodeGen/CodeGenPGO.cpp
>
> Modified: cfe/trunk/lib/CodeGen/CodeGenPGO.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenPGO.cpp?rev=206081&r1=206080&r2=206081&view=diff
>
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CodeGenPGO.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CodeGenPGO.cpp Fri Apr 11 18:06:35 2014
> @@ -331,9 +331,10 @@ namespace {
>      MapRegionCounters(llvm::DenseMap<const Stmt *, unsigned> &CounterMap)
>          : NextCounter(0), CounterMap(CounterMap) {}
>
> -    // Do not traverse the BlockDecl inside a BlockExpr since each
> BlockDecl
> -    // is handled as a separate function.
> -    bool TraverseBlockExpr(BlockExpr *block) { return true; }
> +    // Blocks and lambdas are handled as separate functions, so we need
> not
> +    // traverse them in the parent context.
> +    bool TraverseBlockExpr(BlockExpr *BE) { return true; }
> +    bool TraverseLambdaBody(LambdaExpr *LE) { return true; }
>
>      bool VisitDecl(const Decl *D) {
>        switch (D->getKind()) {
> @@ -431,6 +432,11 @@ namespace {
>        Visit(D->getBody());
>      }
>
> +    // Skip lambda expressions. We visit these as FunctionDecls when we're
> +    // generating them and aren't interested in the body when generating a
> +    // parent context.
> +    void VisitLambdaExpr(const LambdaExpr *LE) {}
> +
>      void VisitObjCMethodDecl(const ObjCMethodDecl *D) {
>        // Counter tracks entry to the method body.
>        RegionCounter Cnt(PGO, D->getBody());
>
> Added: cfe/trunk/test/Profile/Inputs/cxx-lambda.profdata
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Profile/Inputs/cxx-lambda.profdata?rev=206081&view=auto
>
> ==============================================================================
> --- cfe/trunk/test/Profile/Inputs/cxx-lambda.profdata (added)
> +++ cfe/trunk/test/Profile/Inputs/cxx-lambda.profdata Fri Apr 11 18:06:35
> 2014
> @@ -0,0 +1,20 @@
> +cxx-lambda.cpp:_ZZ7lambdasvENK3$_0clEi
> +3
> +3
> +10
> +9
> +9
> +
> +main
> +1
> +1
> +1
> +
> +_Z7lambdasv
> +4
> +4
> +1
> +1
> +10
> +1
> +
>
> Added: cfe/trunk/test/Profile/cxx-lambda.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Profile/cxx-lambda.cpp?rev=206081&view=auto
>
> ==============================================================================
> --- cfe/trunk/test/Profile/cxx-lambda.cpp (added)
> +++ cfe/trunk/test/Profile/cxx-lambda.cpp Fri Apr 11 18:06:35 2014
> @@ -0,0 +1,57 @@
> +// Tests for instrumentation of C++11 lambdas
> +
> +// RUN: %clang_cc1 -x c++ %s -triple %itanium_abi_triple -main-file-name
> cxx-lambda.cpp -std=c++11 -o - -emit-llvm -fprofile-instr-generate > %tgen
> +// RUN: FileCheck --input-file=%tgen -check-prefix=PGOGEN %s
> +// RUN: FileCheck --input-file=%tgen -check-prefix=LMBGEN %s
> +
> +// RUN: %clang_cc1 -x c++ %s -triple %itanium_abi_triple -main-file-name
> cxx-lambda.cpp -std=c++11 -o - -emit-llvm
> -fprofile-instr-use=%S/Inputs/cxx-lambda.profdata > %tuse
> +// RUN: FileCheck --input-file=%tuse -check-prefix=PGOUSE %s
> +// RUN: FileCheck --input-file=%tuse -check-prefix=LMBUSE %s
> +
> +// PGOGEN: @[[LWC:__llvm_profile_counters__Z7lambdasv]] = global [4 x
> i64] zeroinitializer
> +// PGOGEN: @[[MAC:__llvm_profile_counters_main]] = global [1 x i64]
> zeroinitializer
> +// LMBGEN: @[[LFC:"__llvm_profile_counters__ZZ7lambdasvENK3\$_0clEi"]] =
> internal global [3 x i64] zeroinitializer
> +
> +// PGOGEN-LABEL: define void @_Z7lambdasv()
> +// PGOUSE-LABEL: define void @_Z7lambdasv()
> +// PGOGEN: store {{.*}} @[[LWC]], i64 0, i64 0
> +void lambdas() {
> +  int i = 1;
> +
> +  // LMBGEN-LABEL: define internal zeroext i1 @"_ZZ7lambdasvENK3$_0clEi"(
> +  // LMBUSE-LABEL: define internal zeroext i1 @"_ZZ7lambdasvENK3$_0clEi"(
> +  // LMBGEN: store {{.*}} @[[LFC]], i64 0, i64 0
> +  auto f = [&i](int k) {
> +    // LMBGEN: store {{.*}} @[[LFC]], i64 0, i64 1
> +    // LMBUSE: br {{.*}} !prof ![[LF1:[0-9]+]]
> +    if (i > 0) {}
> +    // LMBGEN: store {{.*}} @[[LFC]], i64 0, i64 2
> +    // LMBUSE: br {{.*}} !prof ![[LF2:[0-9]+]]
> +    return k && i;
> +  };
> +
> +  // PGOGEN: store {{.*}} @[[LWC]], i64 0, i64 1
> +  // PGOUSE: br {{.*}} !prof ![[LW1:[0-9]+]]
> +  if (i) {}
> +
> +  // PGOGEN: store {{.*}} @[[LWC]], i64 0, i64 2
> +  // PGOUSE: br {{.*}} !prof ![[LW2:[0-9]+]]
> +  for (i = 0; i < 10; ++i)
> +    f(9 - i);
> +
> +  // PGOGEN: store {{.*}} @[[LWC]], i64 0, i64 3
> +  // PGOUSE: br {{.*}} !prof ![[LW3:[0-9]+]]
> +  if (i) {}
> +}
> +
> +// PGOUSE-DAG: ![[LW1]] = metadata !{metadata !"branch_weights", i32 2,
> i32 1}
> +// PGOUSE-DAG: ![[LW2]] = metadata !{metadata !"branch_weights", i32 11,
> i32 2}
> +// PGOUSE-DAG: ![[LW3]] = metadata !{metadata !"branch_weights", i32 2,
> i32 1}
> +
> +// LMBUSE-DAG: ![[LF1]] = metadata !{metadata !"branch_weights", i32 10,
> i32 2}
> +// LMBUSE-DAG: ![[LF2]] = metadata !{metadata !"branch_weights", i32 10,
> i32 2}
> +
> +int main(int argc, const char *argv[]) {
> +  lambdas();
> +  return 0;
> +}
>
>
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