[CUDA] Disallow exceptions in device code.

Reviewers: tra

Subscribers: cfe-commits, jhen

Differential Revision: https://reviews.llvm.org/D25036

llvm-svn: 282646

7 files changed, 104 insertions, 0 deletions

diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index af484d40038..36b1ebd2299 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -6702,6 +6702,9 @@ def err_cuda_unattributed_constexpr_cannot_overload_device : Error<
   "attribute, or build with -fno-cuda-host-device-constexpr.">;
 def note_cuda_conflicting_device_function_declared_here : Note<
   "conflicting __device__ function declared here">;
+def err_cuda_device_exceptions : Error<
+  "cannot use '%0' in "
+  "%select{__device__|__global__|__host__|__host__ __device__}1 function %2">;
 def err_dynamic_var_init : Error<
     "dynamic initialization is not supported for "
     "__device__, __constant__, and __shared__ variables.">;
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index 1ae2004a6fe..2734e796526 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -9245,6 +9245,16 @@ public:
   /// Otherwise, returns true without emitting any diagnostics.
   bool CheckCUDACall(SourceLocation Loc, FunctionDecl *Callee);
 
+  /// Check whether a 'try' or 'throw' expression is allowed within the current
+  /// context, and raise an error or create a deferred error, as appropriate.
+  ///
+  /// 'try' and 'throw' are never allowed in CUDA __device__ functions, and are
+  /// allowed in __host__ __device__ functions only if those functions are never
+  /// codegen'ed for the device.
+  ///
+  /// ExprTy should be the string "try" or "throw", as appropriate.
+  bool CheckCUDAExceptionExpr(SourceLocation Loc, StringRef ExprTy);
+
   /// Finds a function in \p Matches with highest calling priority
   /// from \p Caller context and erases all functions with lower
   /// calling priority.
diff --git a/clang/lib/Sema/SemaCUDA.cpp b/clang/lib/Sema/SemaCUDA.cpp
index 6f94e54a0cc..b1939a17157 100644
--- a/clang/lib/Sema/SemaCUDA.cpp
+++ b/clang/lib/Sema/SemaCUDA.cpp
@@ -515,3 +515,27 @@ bool Sema::CheckCUDACall(SourceLocation Loc, FunctionDecl *Callee) {
   }
   return true;
 }
+
+bool Sema::CheckCUDAExceptionExpr(SourceLocation Loc, StringRef ExprTy) {
+  assert(getLangOpts().CUDA && "Should only be called during CUDA compilation");
+  FunctionDecl *CurFn = dyn_cast<FunctionDecl>(CurContext);
+  if (!CurFn)
+    return true;
+  CUDAFunctionTarget Target = IdentifyCUDATarget(CurFn);
+
+  // Raise an error immediately if this is a __global__ or __device__ function.
+  // If it's a __host__ __device__ function, enqueue a deferred error which will
+  // be emitted if the function is codegen'ed for device.
+  if (Target == CFT_Global || Target == CFT_Device) {
+    Diag(Loc, diag::err_cuda_device_exceptions) << ExprTy << Target << CurFn;
+    return false;
+  }
+  if (Target == CFT_HostDevice && getLangOpts().CUDAIsDevice) {
+    PartialDiagnostic ErrPD{PartialDiagnostic::NullDiagnostic()};
+    ErrPD.Reset(diag::err_cuda_device_exceptions);
+    ErrPD << ExprTy << Target << CurFn;
+    CurFn->addDeferredDiag({Loc, std::move(ErrPD)});
+    return false;
+  }
+  return true;
+}
diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index a0bf324a714..42888badd2e 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -683,6 +683,10 @@ ExprResult Sema::BuildCXXThrow(SourceLocation OpLoc, Expr *Ex,
       !getSourceManager().isInSystemHeader(OpLoc))
     Diag(OpLoc, diag::err_exceptions_disabled) << "throw";
 
+  // Exceptions aren't allowed in CUDA device code.
+  if (getLangOpts().CUDA)
+    CheckCUDAExceptionExpr(OpLoc, "throw");
+
   if (getCurScope() && getCurScope()->isOpenMPSimdDirectiveScope())
     Diag(OpLoc, diag::err_omp_simd_region_cannot_use_stmt) << "throw";
 
diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index 977d7447d73..901f875840e 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -3644,6 +3644,10 @@ StmtResult Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock,
       !getSourceManager().isInSystemHeader(TryLoc))
     Diag(TryLoc, diag::err_exceptions_disabled) << "try";
 
+  // Exceptions aren't allowed in CUDA device code.
+  if (getLangOpts().CUDA)
+    CheckCUDAExceptionExpr(TryLoc, "try");
+
   if (getCurScope() && getCurScope()->isOpenMPSimdDirectiveScope())
     Diag(TryLoc, diag::err_omp_simd_region_cannot_use_stmt) << "try";
 
diff --git a/clang/test/SemaCUDA/exceptions-host-device.cu b/clang/test/SemaCUDA/exceptions-host-device.cu
new file mode 100644
index 00000000000..3f323469ac1
--- /dev/null
+++ b/clang/test/SemaCUDA/exceptions-host-device.cu
@@ -0,0 +1,38 @@
+// RUN: %clang_cc1 -fcxx-exceptions -fcuda-is-device -verify %s -S -o /dev/null
+// RUN: %clang_cc1 -fcxx-exceptions -verify -DHOST %s -S -o /dev/null
+
+#include "Inputs/cuda.h"
+
+// Check that it's an error to use 'try' and 'throw' from a __host__ __device__
+// function if and only if it's codegen'ed for device.
+
+#ifdef HOST
+// expected-no-diagnostics
+#endif
+
+__host__ __device__ void hd1() {
+  throw NULL;
+  try {} catch(void*) {}
+#ifndef HOST
+  // expected-error@-3 {{cannot use 'throw' in __host__ __device__ function 'hd1'}}
+  // expected-error@-3 {{cannot use 'try' in __host__ __device__ function 'hd1'}}
+#endif
+}
+
+// No error, never instantiated on device.
+inline __host__ __device__ void hd2() {
+  throw NULL;
+  try {} catch(void*) {}
+}
+void call_hd2() { hd2(); }
+
+// Error, instantiated on device.
+inline __host__ __device__ void hd3() {
+  throw NULL;
+  try {} catch(void*) {}
+#ifndef HOST
+  // expected-error@-3 {{cannot use 'throw' in __host__ __device__ function 'hd3'}}
+  // expected-error@-3 {{cannot use 'try' in __host__ __device__ function 'hd3'}}
+#endif
+}
+__device__ void call_hd3() { hd3(); }
diff --git a/clang/test/SemaCUDA/exceptions.cu b/clang/test/SemaCUDA/exceptions.cu
new file mode 100644
index 00000000000..75586bc4a97
--- /dev/null
+++ b/clang/test/SemaCUDA/exceptions.cu
@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -fcxx-exceptions -fcuda-is-device -fsyntax-only -verify %s
+// RUN: %clang_cc1 -fcxx-exceptions -fsyntax-only -verify %s
+
+#include "Inputs/cuda.h"
+
+void host() {
+  throw NULL;
+  try {} catch(void*) {}
+}
+__device__ void device() {
+  throw NULL;
+  // expected-error@-1 {{cannot use 'throw' in __device__ function 'device'}}
+  try {} catch(void*) {}
+  // expected-error@-1 {{cannot use 'try' in __device__ function 'device'}}
+}
+__global__ void kernel() {
+  throw NULL;
+  // expected-error@-1 {{cannot use 'throw' in __global__ function 'kernel'}}
+  try {} catch(void*) {}
+  // expected-error@-1 {{cannot use 'try' in __global__ function 'kernel'}}
+}