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

Richard Smith richard at metafoo.co.uk
Mon Apr 14 19:03:03 PDT 2014


They're intended for use by OpenMP, but I think the CodeGen parts of that
haven't quite landed yet. In the mean time, the pragma you found is a good
way to get test coverage here. Thanks!

On Mon, Apr 14, 2014 at 6:00 PM, Justin Bogner <mail at justinbogner.com>wrote:

> Good catch! Turns out CapturedStmt wasn't being handled *at all* by
> instrumentation based profiling. I've fixed that in r206231.
>
> On that note, what are CapturedStmts for? Is the test in r206231
> sufficient?
>
> Richard Smith <richard at metafoo.co.uk> writes:
> > 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;
> >     +}
> >
> >     _______________________________________________
> >     cfe-commits mailing list
> >     cfe-commits at cs.uiuc.edu
> >     http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
>
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