[CUDA] Mark device functions as nounwind.

Summary:
This prevents clang from emitting 'invoke's and catch statements.

Things previously mostly worked thanks to TryToMarkNoThrow() in
CodeGenFunction.  But this is not a proper IPO, and it doesn't properly
handle cases like mutual recursion.

Fixes bug 30593.

Reviewers: tra

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D25166

llvm-svn: 283272

2 files changed, 7 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index f441bf4eda1..955b86a38b2 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -1814,6 +1814,9 @@ void CodeGenModule::ConstructAttributeList(
     // them).  LLVM will remove this attribute where it safely can.
     FuncAttrs.addAttribute(llvm::Attribute::Convergent);
 
+    // Exceptions aren't supported in CUDA device code.
+    FuncAttrs.addAttribute(llvm::Attribute::NoUnwind);
+
     // Respect -fcuda-flush-denormals-to-zero.
     if (getLangOpts().CUDADeviceFlushDenormalsToZero)
       FuncAttrs.addAttribute("nvptx-f32ftz", "true");
diff --git a/clang/lib/CodeGen/CGException.cpp b/clang/lib/CodeGen/CGException.cpp
index 4a7dc4205e0..57ac44e6b17 100644
--- a/clang/lib/CodeGen/CGException.cpp
+++ b/clang/lib/CodeGen/CGException.cpp
@@ -698,6 +698,10 @@ llvm::BasicBlock *CodeGenFunction::getInvokeDestImpl() {
       return nullptr;
   }
 
+  // CUDA device code doesn't have exceptions.
+  if (LO.CUDA && LO.CUDAIsDevice)
+    return nullptr;
+
   // Check the innermost scope for a cached landing pad.  If this is
   // a non-EH cleanup, we'll check enclosing scopes in EmitLandingPad.
   llvm::BasicBlock *LP = EHStack.begin()->getCachedLandingPad();