Author: Heejin Ahn Date: 2020-05-19T01:16:09-07:00 New Revision: d94bacbcf87a06abc0c1fc3405406399460debc3
URL: https://github.com/llvm/llvm-project/commit/d94bacbcf87a06abc0c1fc3405406399460debc3 DIFF: https://github.com/llvm/llvm-project/commit/d94bacbcf87a06abc0c1fc3405406399460debc3.diff LOG: [WebAssembly] Handle exception specifications Summary: Wasm currently does not fully handle exception specifications. Rather than crashing, - This treats `throw()` in the same way as `noexcept`. - This ignores and prints a warning for `throw(type, ..)`, for a temporary measure. This warning is controlled by `-Wwasm-exception-spec`, which is on by default. You can suppress the warning by using `-Wno-wasm-exception-spec`. Reviewers: dschuff Subscribers: sbc100, jgravelle-google, sunfish, cfe-commits Tags: #clang Differential Revision: https://reviews.llvm.org/D80061 Added: Modified: clang/docs/DiagnosticsReference.rst clang/include/clang/Basic/DiagnosticGroups.td clang/include/clang/Basic/DiagnosticSemaKinds.td clang/lib/CodeGen/CGException.cpp clang/test/CodeGenCXX/wasm-eh.cpp Removed: ################################################################################ diff --git a/clang/docs/DiagnosticsReference.rst b/clang/docs/DiagnosticsReference.rst index 402ec9d4eba6..2fab8b5f3026 100644 --- a/clang/docs/DiagnosticsReference.rst +++ b/clang/docs/DiagnosticsReference.rst @@ -14010,3 +14010,10 @@ This diagnostic is enabled by default. +------------------------------------------------------------------------+ +-Wwasm-exception-spec +--------------------- +**Diagnostic text:** + ++----------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`dynamic exception specifications with types are currently ignored in wasm`| ++----------------------------------------------------------------------------------------------------------------+ diff --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td index c9104da66f1f..3f0521615a5e 100644 --- a/clang/include/clang/Basic/DiagnosticGroups.td +++ b/clang/include/clang/Basic/DiagnosticGroups.td @@ -1207,3 +1207,5 @@ Note that the warning is disabled by default, so -Wmax-tokens must be used in addition with the pragmas or -fmax-tokens flag to get any warnings. }]; } + +def WebAssemblyExceptionSpec : DiagGroup<"wasm-exception-spec">; diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td index 55d35be8f939..d415802916b6 100644 --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td @@ -1590,6 +1590,9 @@ def err_exception_spec_cycle : Error< "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 : ExtWarn< + "dynamic exception specifications with types are currently ignored in wasm">, + InGroup<WebAssemblyExceptionSpec>; // C++ access checking def err_class_redeclared_with_ diff erent_access : Error< diff --git a/clang/lib/CodeGen/CGException.cpp b/clang/lib/CodeGen/CGException.cpp index a5dae1b32e69..d821eb2d5595 100644 --- a/clang/lib/CodeGen/CGException.cpp +++ b/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 @@ void CodeGenFunction::EmitStartEHSpec(const Decl *D) { // 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 @@ void CodeGenFunction::EmitEndEHSpec(const Decl *D) { // 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(); diff --git a/clang/test/CodeGenCXX/wasm-eh.cpp b/clang/test/CodeGenCXX/wasm-eh.cpp index 17f325bd9eba..cd18ed406d7e 100644 --- a/clang/test/CodeGenCXX/wasm-eh.cpp +++ b/clang/test/CodeGenCXX/wasm-eh.cpp @@ -7,7 +7,6 @@ // RUN: rm -f %S/wasm-eh.ll // 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; @@ -391,9 +390,34 @@ void test8() { // CHECK: unreachable +// 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 2>&1 | FileCheck %s --check-prefix=WARNING-DEFAULT +// RUN: %clang_cc1 %s -triple wasm32-unknown-unknown -fms-extensions -fexceptions -fcxx-exceptions -fwasm-exceptions -target-feature +exception-handling -Wwasm-exception-spec -emit-llvm -o - -std=c++11 2>&1 | FileCheck %s --check-prefix=WARNING-ON +// RUN: %clang_cc1 %s -triple wasm32-unknown-unknown -fms-extensions -fexceptions -fcxx-exceptions -fwasm-exceptions -target-feature +exception-handling -Wno-wasm-exception-spec -emit-llvm -o - -std=c++11 2>&1 | FileCheck %s --check-prefix=WARNING-OFF + +// Wasm ignores dynamic exception specifications with types at the moment. This +// is controlled by -Wwasm-exception-spec, which is on by default. This warning +// can be suppressed with -Wno-wasm-exception-spec. +// Checks if a warning message is correctly printed or not printed depending on +// the options. +void test9() throw(int) { +} +// WARNING-DEFAULT: warning: dynamic exception specifications with types are currently ignored in wasm +// WARNING-ON: warning: dynamic exception specifications with types are currently ignored in wasm +// WARNING-OFF-NOT: 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-DEFAULT: warning: 'test10' has a non-throwing exception specification but can still throw +// WARNING-DEFAULT: 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 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
