[PATCH] D79655: [WebAssembly] Handle exception specifications

[Heejin Ahn via Phabricator via cfe-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rGbca347508c86: [WebAssembly] Handle exception specifications (authored by aheejin).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D79655/new/

https://reviews.llvm.org/D79655

Files:
  clang/include/clang/Basic/DiagnosticSemaKinds.td
  clang/lib/CodeGen/CGException.cpp
  clang/test/CodeGenCXX/wasm-eh.cpp


Index: clang/test/CodeGenCXX/wasm-eh.cpp
===================================================================
--- clang/test/CodeGenCXX/wasm-eh.cpp
+++ clang/test/CodeGenCXX/wasm-eh.cpp
@@ -1,7 +1,6 @@
 // REQUIRES: webassembly-registered-target
 // RUN: %clang_cc1 %s -triple wasm32-unknown-unknown -fms-extensions -fexceptions -fcxx-exceptions -fwasm-exceptions -target-feature +exception-handling -emit-llvm -o - -std=c++11 | FileCheck %s
 // RUN: %clang_cc1 %s -triple wasm64-unknown-unknown -fms-extensions -fexceptions -fcxx-exceptions -fwasm-exceptions -target-feature +exception-handling -emit-llvm -o - -std=c++11 | FileCheck %s
-// RUN: %clang_cc1 %s -triple wasm32-unknown-unknown -fms-extensions -fexceptions -fcxx-exceptions -fwasm-exceptions -target-feature +exception-handling -S -o - -std=c++11 | FileCheck %s --check-prefix=ASSEMBLY
 
 void may_throw();
 void dont_throw() noexcept;
@@ -385,9 +384,27 @@
 
 // CHECK:   unreachable
 
+// RUN: %clang_cc1 %s -triple wasm32-unknown-unknown -fms-extensions -fexceptions -fcxx-exceptions -fwasm-exceptions -target-feature +exception-handling -emit-llvm -std=c++11 2>&1 | FileCheck %s --check-prefix=WARNING
+
+// Wasm ignores dynamic exception specifications with types at the moment.
+// Checks if a warning message is printed.
+void test9() throw(int) {
+}
+// WARNING: warning: dynamic exception specifications with types are currently ignored in wasm
+
+// Wasm curremtly treats 'throw()' in the same way as 'noexept'. Check if the
+// same warning message is printed as if when a 'noexcept' function throws.
+void test10() throw() {
+  throw 3;
+}
+// WARNING: warning: 'test10' has a non-throwing exception specification but can still throw
+// WARNING: function declared non-throwing here
+
 // Here we only check if the command enables wasm exception handling in the
 // backend so that exception handling instructions can be generated in .s file.
 
+// RUN: %clang_cc1 %s -triple wasm32-unknown-unknown -fms-extensions -fexceptions -fcxx-exceptions -fwasm-exceptions -target-feature +exception-handling -S -o - -std=c++11 | FileCheck %s --check-prefix=ASSEMBLY
+
 // ASSEMBLY: try
 // ASSEMBLY: catch
 // ASSEMBLY: rethrow
Index: clang/lib/CodeGen/CGException.cpp
===================================================================
--- clang/lib/CodeGen/CGException.cpp
+++ clang/lib/CodeGen/CGException.cpp
@@ -20,6 +20,7 @@
 #include "clang/AST/StmtCXX.h"
 #include "clang/AST/StmtObjC.h"
 #include "clang/AST/StmtVisitor.h"
+#include "clang/Basic/DiagnosticSema.h"
 #include "clang/Basic/TargetBuiltins.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Intrinsics.h"
@@ -468,6 +469,18 @@
     // encode these in an object file but MSVC doesn't do anything with it.
     if (getTarget().getCXXABI().isMicrosoft())
       return;
+    // In wasm we currently treat 'throw()' in the same way as 'noexcept'. In
+    // case of throw with types, we ignore it and print a warning for now.
+    // TODO Correctly handle exception specification in wasm
+    if (getTarget().getCXXABI() == TargetCXXABI::WebAssembly) {
+      if (EST == EST_DynamicNone)
+        EHStack.pushTerminate();
+      else
+        CGM.getDiags().Report(D->getLocation(),
+                              diag::warn_wasm_dynamic_exception_spec_ignored)
+            << FD->getExceptionSpecSourceRange();
+      return;
+    }
     unsigned NumExceptions = Proto->getNumExceptions();
     EHFilterScope *Filter = EHStack.pushFilter(NumExceptions);
 
@@ -544,6 +557,14 @@
     // encode these in an object file but MSVC doesn't do anything with it.
     if (getTarget().getCXXABI().isMicrosoft())
       return;
+    // In wasm we currently treat 'throw()' in the same way as 'noexcept'. In
+    // case of throw with types, we ignore it and print a warning for now.
+    // TODO Correctly handle exception specification in wasm
+    if (getTarget().getCXXABI() == TargetCXXABI::WebAssembly) {
+      if (EST == EST_DynamicNone)
+        EHStack.popTerminate();
+      return;
+    }
     EHFilterScope &filterScope = cast<EHFilterScope>(*EHStack.begin());
     emitFilterDispatchBlock(*this, filterScope);
     EHStack.popFilter();
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -1590,6 +1590,8 @@
   "exception specification of %0 uses itself">;
 def err_exception_spec_incomplete_type : Error<
   "exception specification needed for member of incomplete class %0">;
+def warn_wasm_dynamic_exception_spec_ignored : Warning<
+  "dynamic exception specifications with types are currently ignored in wasm">;
 
 // C++ access checking
 def err_class_redeclared_with_different_access : Error<


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