[cfe-commits] r110163 - in /cfe/trunk: lib/CodeGen/CodeGenFunction.cpp test/CodeGen/unwind-attr.c test/CodeGenCXX/global-init.cpp

[Chris Lattner]

On Aug 3, 2010, at 3:46 PM, John McCall wrote:

> Author: rjmccall
> Date: Tue Aug  3 17:46:07 2010
> New Revision: 110163
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=110163&view=rev
> Log:
> Do a very simple pass over every function we emit to infer whether we can
> mark it nounwind based on whether it contains any non-nounwind calls.
> <rdar://problem/8087431>

Thanks John!

-Chris

> 
> 
> Modified:
>    cfe/trunk/lib/CodeGen/CodeGenFunction.cpp
>    cfe/trunk/test/CodeGen/unwind-attr.c
>    cfe/trunk/test/CodeGenCXX/global-init.cpp
> 
> Modified: cfe/trunk/lib/CodeGen/CodeGenFunction.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenFunction.cpp?rev=110163&r1=110162&r2=110163&view=diff
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CodeGenFunction.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CodeGenFunction.cpp Tue Aug  3 17:46:07 2010
> @@ -311,6 +311,19 @@
>   EmitStmt(FD->getBody());
> }
> 
> +/// Tries to mark the given function nounwind based on the
> +/// non-existence of any throwing calls within it.  We believe this is
> +/// lightweight enough to do at -O0.
> +static void TryMarkNoThrow(llvm::Function *F) {
> +  for (llvm::Function::iterator FI = F->begin(), FE = F->end(); FI != FE; ++FI)
> +    for (llvm::BasicBlock::iterator
> +           BI = FI->begin(), BE = FI->end(); BI != BE; ++BI)
> +      if (llvm::CallInst *Call = dyn_cast<llvm::CallInst>(&*BI))
> +        if (!Call->doesNotThrow())
> +          return;
> +  F->setDoesNotThrow(true);
> +}
> +
> void CodeGenFunction::GenerateCode(GlobalDecl GD, llvm::Function *Fn) {
>   const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl());
> 
> @@ -369,6 +382,11 @@
> 
>   // Emit the standard function epilogue.
>   FinishFunction(BodyRange.getEnd());
> +
> +  // If we haven't marked the function nothrow through other means, do
> +  // a quick pass now to see if we can.
> +  if (!CurFn->doesNotThrow())
> +    TryMarkNoThrow(CurFn);
> }
> 
> /// ContainsLabel - Return true if the statement contains a label in it.  If
> 
> Modified: cfe/trunk/test/CodeGen/unwind-attr.c
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/unwind-attr.c?rev=110163&r1=110162&r2=110163&view=diff
> ==============================================================================
> --- cfe/trunk/test/CodeGen/unwind-attr.c (original)
> +++ cfe/trunk/test/CodeGen/unwind-attr.c Tue Aug  3 17:46:07 2010
> @@ -1,6 +1,16 @@
> -// RUN: %clang_cc1 -fexceptions -emit-llvm -o - %s | grep "@foo()" | not grep nounwind
> -// RUN: %clang_cc1 -emit-llvm -o - %s | grep "@foo()" | grep nounwind 
> +// RUN: %clang_cc1 -fexceptions -emit-llvm -o - %s | FileCheck %s
> +// RUN: %clang_cc1 -emit-llvm -o - %s | FileCheck -check-prefix NOEXC %s
> 
> -int foo(void) {
> -  return 0;
> +int opaque();
> +
> +// CHECK:       define [[INT:i.*]] @test0() {
> +// CHECK-NOEXC: define [[INT:i.*]] @test0() nounwind {
> +int test0(void) {
> +  return opaque();
> +}
> +
> +// <rdar://problem/8087431>: locally infer nounwind at -O0
> +// CHECK:       define [[INT:i.*]] @test1() nounwind {
> +// CHECK-NOEXC: define [[INT:i.*]] @test1() nounwind {
> +int test1(void) {
> }
> 
> Modified: cfe/trunk/test/CodeGenCXX/global-init.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/global-init.cpp?rev=110163&r1=110162&r2=110163&view=diff
> ==============================================================================
> --- cfe/trunk/test/CodeGenCXX/global-init.cpp (original)
> +++ cfe/trunk/test/CodeGenCXX/global-init.cpp Tue Aug  3 17:46:07 2010
> @@ -36,7 +36,7 @@
>   const int y = x - 1; // This gets deferred.
>   const int z = ~y;    // This also gets deferred, but gets "undeferred" before y.
>   int test() { return z; }
> -// CHECK:      define i32 @_ZN5test14testEv() {
> +// CHECK:      define i32 @_ZN5test14testEv()
> 
>   // All of these initializers end up delayed, so we check them later.
> }
> 
> 
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