[WebAssembly] Add -fwasm-exceptions for wasm EH

Summary:
This adds `-fwasm-exceptions` (in similar fashion with
`-fdwarf-exceptions` or `-fsjlj-exceptions`) that turns on everything
with wasm exception handling from the frontend to the backend.

We currently have `-mexception-handling` in clang frontend, but this is
only about the architecture capability and does not turn on other
necessary options such as the exception model in the backend. (This can
be turned on with `llc -exception-model=wasm`, but llc is not invoked
separately as a command line tool, so this option has to be transferred
from clang.)

Turning on `-fwasm-exceptions` in clang also turns on
`-mexception-handling` if not specified, and will error out if
`-mno-exception-handling` is specified.

Reviewers: dschuff, tlively, sbc100

Subscribers: aprantl, jgravelle-google, sunfish, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D67208

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@371708 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Basic/LangOptions.def b/include/clang/Basic/LangOptions.def
index 31aca2b0d695087c2b1cf593ec50fe57db3d7711..dec281e7935ce885ce5795955d0b24c8a5d39fbc 100644 (file)
--- a/include/clang/Basic/LangOptions.def
+++ b/include/clang/Basic/LangOptions.def
@@ -128,6 +128,7 @@ LANGOPT(CXXExceptions     , 1, 0, "C++ exceptions")
 LANGOPT(DWARFExceptions   , 1, 0, "dwarf exception handling")
 LANGOPT(SjLjExceptions    , 1, 0, "setjmp-longjump exception handling")
 LANGOPT(SEHExceptions     , 1, 0, "SEH .xdata exception handling")
+LANGOPT(WasmExceptions    , 1, 0, "WebAssembly exception handling")
 LANGOPT(ExternCNoUnwind   , 1, 0, "Assume extern C functions don't unwind")
 LANGOPT(TraditionalCPP    , 1, 0, "traditional CPP emulation")
 LANGOPT(RTTI              , 1, 1, "run-time type information")

diff --git a/include/clang/Driver/Options.td b/include/clang/Driver/Options.td
index 01c0cd2db609cca9e12edebad26b8da51722d8e4..57bab1e1c48b6abc7bc5019323275f8959f855e8 100644 (file)
--- a/include/clang/Driver/Options.td
+++ b/include/clang/Driver/Options.td
@@ -904,6 +904,8 @@ def fsjlj_exceptions : Flag<["-"], "fsjlj-exceptions">, Group<f_Group>,
   Flags<[CC1Option]>, HelpText<"Use SjLj style exceptions">;
 def fseh_exceptions : Flag<["-"], "fseh-exceptions">, Group<f_Group>,
   Flags<[CC1Option]>, HelpText<"Use SEH style exceptions">;
+def fwasm_exceptions : Flag<["-"], "fwasm-exceptions">, Group<f_Group>,
+  Flags<[CC1Option]>, HelpText<"Use WebAssembly style exceptions">;
 def fexcess_precision_EQ : Joined<["-"], "fexcess-precision=">,
     Group<clang_ignored_gcc_optimization_f_Group>;
 def : Flag<["-"], "fexpensive-optimizations">, Group<clang_ignored_gcc_optimization_f_Group>;

diff --git a/lib/CodeGen/BackendUtil.cpp b/lib/CodeGen/BackendUtil.cpp
index 251b1fce6d85e2458940843bb0719dd5b0b58e7b..71ae8fd4fb09c68c29a2478f68b26a76c2b4d0fa 100644 (file)
--- a/lib/CodeGen/BackendUtil.cpp
+++ b/lib/CodeGen/BackendUtil.cpp
@@ -468,6 +468,8 @@ static void initTargetOptions(llvm::TargetOptions &Options,
     Options.ExceptionModel = llvm::ExceptionHandling::WinEH;
   if (LangOpts.DWARFExceptions)
     Options.ExceptionModel = llvm::ExceptionHandling::DwarfCFI;
+  if (LangOpts.WasmExceptions)
+    Options.ExceptionModel = llvm::ExceptionHandling::Wasm;
 
   Options.NoInfsFPMath = CodeGenOpts.NoInfsFPMath;
   Options.NoNaNsFPMath = CodeGenOpts.NoNaNsFPMath;

diff --git a/lib/CodeGen/CGException.cpp b/lib/CodeGen/CGException.cpp
index 4c94cfb23343c71d08b28d18b52d45d0c25a157a..645d7a878e3b13db71dbd868f65161cf0350b4d7 100644 (file)
--- a/lib/CodeGen/CGException.cpp
+++ b/lib/CodeGen/CGException.cpp
@@ -165,10 +165,7 @@ static const EHPersonality &getCXXPersonality(const TargetInfo &Target,
     return EHPersonality::GNU_CPlusPlus;
   if (L.SEHExceptions)
     return EHPersonality::GNU_CPlusPlus_SEH;
-  // Wasm EH is a non-MVP feature for now.
-  if (Target.hasFeature("exception-handling") &&
-      (T.getArch() == llvm::Triple::wasm32 ||
-       T.getArch() == llvm::Triple::wasm64))
+  if (L.WasmExceptions)
     return EHPersonality::GNU_Wasm_CPlusPlus;
   return EHPersonality::GNU_CPlusPlus;
 }

diff --git a/lib/Driver/ToolChains/Clang.cpp b/lib/Driver/ToolChains/Clang.cpp
index 9b2d4d874a26be429ff5d6d86d52b71cc56a4cee..6aff423bd1896053e142fbfe700f527c2942bc62 100644 (file)
--- a/lib/Driver/ToolChains/Clang.cpp
+++ b/lib/Driver/ToolChains/Clang.cpp
@@ -4981,9 +4981,9 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     addExceptionArgs(Args, InputType, TC, KernelOrKext, Runtime, CmdArgs);
 
   // Handle exception personalities
-  Arg *A = Args.getLastArg(options::OPT_fsjlj_exceptions,
-                           options::OPT_fseh_exceptions,
-                           options::OPT_fdwarf_exceptions);
+  Arg *A = Args.getLastArg(
+      options::OPT_fsjlj_exceptions, options::OPT_fseh_exceptions,
+      options::OPT_fdwarf_exceptions, options::OPT_fwasm_exceptions);
   if (A) {
     const Option &Opt = A->getOption();
     if (Opt.matches(options::OPT_fsjlj_exceptions))
@@ -4992,6 +4992,8 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
       CmdArgs.push_back("-fseh-exceptions");
     if (Opt.matches(options::OPT_fdwarf_exceptions))
       CmdArgs.push_back("-fdwarf-exceptions");
+    if (Opt.matches(options::OPT_fwasm_exceptions))
+      CmdArgs.push_back("-fwasm-exceptions");
   } else {
     switch (TC.GetExceptionModel(Args)) {
     default:

diff --git a/lib/Driver/ToolChains/WebAssembly.cpp b/lib/Driver/ToolChains/WebAssembly.cpp
index de8325d46e9fed2fccdb30f094c5f5dc6d94389f..a9e5ec1c9cfe8681a95bca7164f62b3af92b52dd 100644 (file)
--- a/lib/Driver/ToolChains/WebAssembly.cpp
+++ b/lib/Driver/ToolChains/WebAssembly.cpp
@@ -166,6 +166,26 @@ void WebAssembly::addClangTargetOptions(const ArgList &DriverArgs,
     CC1Args.push_back("-target-feature");
     CC1Args.push_back("+mutable-globals");
   }
+
+  if (DriverArgs.getLastArg(options::OPT_fwasm_exceptions)) {
+    // '-fwasm-exceptions' is not compatible with '-mno-exception-handling'
+    if (DriverArgs.hasFlag(options::OPT_mno_exception_handing,
+                           options::OPT_mexception_handing, false))
+      getDriver().Diag(diag::err_drv_argument_not_allowed_with)
+          << "-fwasm-exceptions"
+          << "-mno-exception-handling";
+    // '-fwasm-exceptions' is not compatible with
+    // '-mllvm -enable-emscripten-cxx-exceptions'
+    for (const Arg *A : DriverArgs.filtered(options::OPT_mllvm)) {
+      if (StringRef(A->getValue(0)) == "-enable-emscripten-cxx-exceptions")
+        getDriver().Diag(diag::err_drv_argument_not_allowed_with)
+            << "-fwasm-exceptions"
+            << "-mllvm -enable-emscripten-cxx-exceptions";
+    }
+    // '-fwasm-exceptions' implies exception-handling
+    CC1Args.push_back("-target-feature");
+    CC1Args.push_back("+exception-handling");
+  }
 }
 
 ToolChain::RuntimeLibType WebAssembly::GetDefaultRuntimeLibType() const {

diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 38d5694e7cd0e35969a4b13715888bb932b7ce59..f051573e5aed0ed755502a4136e4f95a8644ce1f 100644 (file)
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -2686,9 +2686,9 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
       Opts.FixedPoint;
 
   // Handle exception personalities
-  Arg *A = Args.getLastArg(options::OPT_fsjlj_exceptions,
-                           options::OPT_fseh_exceptions,
-                           options::OPT_fdwarf_exceptions);
+  Arg *A = Args.getLastArg(
+      options::OPT_fsjlj_exceptions, options::OPT_fseh_exceptions,
+      options::OPT_fdwarf_exceptions, options::OPT_fwasm_exceptions);
   if (A) {
     const Option &Opt = A->getOption();
     llvm::Triple T(TargetOpts.Triple);
@@ -2699,6 +2699,7 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
     Opts.SjLjExceptions = Opt.matches(options::OPT_fsjlj_exceptions);
     Opts.SEHExceptions = Opt.matches(options::OPT_fseh_exceptions);
     Opts.DWARFExceptions = Opt.matches(options::OPT_fdwarf_exceptions);
+    Opts.WasmExceptions = Opt.matches(options::OPT_fwasm_exceptions);
   }
 
   Opts.ExternCNoUnwind = Args.hasArg(OPT_fexternc_nounwind);

diff --git a/test/CodeGenCXX/wasm-eh.cpp b/test/CodeGenCXX/wasm-eh.cpp
index 5d5cb6ba1cfd00c8b6bfa08fe5db341cf8567e68..6005701f234865e78f64a2825054409408ade10f 100644 (file)
--- a/test/CodeGenCXX/wasm-eh.cpp
+++ b/test/CodeGenCXX/wasm-eh.cpp
@@ -1,5 +1,6 @@
-// RUN: %clang_cc1 %s -triple wasm32-unknown-unknown -fms-extensions -fexceptions -fcxx-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 -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 -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;
@@ -382,3 +383,11 @@ void test8() {
 // CHECK:   cleanupret from %[[CLEANUPPAD1]] unwind to caller
 
 // CHECK:   unreachable
+
+// 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.
+
+// ASSEMBLY: try
+// ASSEMBLY: catch
+// ASSEMBLY: rethrow
+// ASSEMBLY: end_try

diff --git a/test/Driver/wasm-toolchain.c b/test/Driver/wasm-toolchain.c
index 263fcf7f397b2a944b2f1dba3eca39ab526bc498..e222d618d228d3803a3819311167696f4defcc16 100644 (file)
--- a/test/Driver/wasm-toolchain.c
+++ b/test/Driver/wasm-toolchain.c
@@ -73,6 +73,25 @@
 // RUN:   | FileCheck -check-prefix=PTHREAD_NO_MUT_GLOBALS %s
 // PTHREAD_NO_MUT_GLOBALS: invalid argument '-pthread' not allowed with '-mno-mutable-globals'
 
+// '-fwasm-exceptions' sets +exception-handling
+// RUN: %clang -### -no-canonical-prefixes -target wasm32-unknown-unknown \
+// RUN:    --sysroot=/foo %s -fwasm-exceptions 2>&1 \
+// RUN:  | FileCheck -check-prefix=WASM_EXCEPTIONS %s
+// WASM_EXCEPTIONS: clang{{.*}}" "-cc1" {{.*}} "-target-feature" "+exception-handling"
+
+// '-fwasm-exceptions' not allowed with '-mno-exception-handling'
+// RUN: %clang -### -no-canonical-prefixes -target wasm32-unknown-unknown \
+// RUN:     --sysroot=/foo %s -fwasm-exceptions -mno-exception-handling 2>&1 \
+// RUN:   | FileCheck -check-prefix=WASM_EXCEPTIONS_NO_EH %s
+// WASM_EXCEPTIONS_NO_EH: invalid argument '-fwasm-exceptions' not allowed with '-mno-exception-handling'
+
+// '-fwasm-exceptions' not allowed with
+// '-mllvm -enable-emscripten-cxx-exceptions'
+// RUN: %clang -### -no-canonical-prefixes -target wasm32-unknown-unknown \
+// RUN:     --sysroot=/foo %s -fwasm-exceptions -mllvm -enable-emscripten-cxx-exceptions 2>&1 \
+// RUN:   | FileCheck -check-prefix=WASM_EXCEPTIONS_EMSCRIPTEN_EH %s
+// WASM_EXCEPTIONS_EMSCRIPTEN_EH: invalid argument '-fwasm-exceptions' not allowed with '-mllvm -enable-emscripten-cxx-exceptions'
+
 // RUN: %clang %s -### -fsanitize=address -target wasm32-unknown-emscripten 2>&1 | FileCheck -check-prefix=CHECK-ASAN-EMSCRIPTEN %s
 // CHECK-ASAN-EMSCRIPTEN: "-fsanitize=address"
 // CHECK-ASAN-EMSCRIPTEN: "-fsanitize-address-globals-dead-stripping"