diff --git a/clang/test/CodeGen/WebAssembly/wasm-eh.ll b/clang/test/CodeGen/WebAssembly/wasm-eh.ll new file mode 100644 --- /dev/null +++ b/clang/test/CodeGen/WebAssembly/wasm-eh.ll @@ -0,0 +1,38 @@ +; REQUIRES: webassembly-registered-target +; RUN: %clang %s -target wasm32-unknown-unknown -fwasm-exceptions -c -S -o - | FileCheck %s + +; This tests whether clang driver can take -fwasm-exceptions and compile bitcode +; files using Wasm EH. + +; CHECK-LABEL: test +; CHECK: try +; CHECK: call foo +; CHECK: catch __cpp_exception +; CHECK: end +define void @test() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) { +entry: + invoke void @foo() + to label %try.cont unwind label %catch.dispatch + +catch.dispatch: ; preds = %entry + %0 = catchswitch within none [label %catch.start] unwind to caller + +catch.start: ; preds = %catch.dispatch + %1 = catchpad within %0 [i8* null] + %2 = call i8* @llvm.wasm.get.exception(token %1) + %3 = call i32 @llvm.wasm.get.ehselector(token %1) + %4 = call i8* @__cxa_begin_catch(i8* %2) #2 [ "funclet"(token %1) ] + call void @__cxa_end_catch() [ "funclet"(token %1) ] + catchret from %1 to label %try.cont + +try.cont: ; preds = %entry, %catch.start + ret void +} + +declare void @foo() +declare i32 @__gxx_wasm_personality_v0(...) +declare i8* @llvm.wasm.get.exception(token) +declare i32 @llvm.wasm.get.ehselector(token) +declare i8* @__cxa_begin_catch(i8*) +declare void @__cxa_end_catch() + diff --git a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCAsmInfo.cpp b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCAsmInfo.cpp --- a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCAsmInfo.cpp +++ b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCAsmInfo.cpp @@ -14,11 +14,15 @@ #include "WebAssemblyMCAsmInfo.h" #include "llvm/ADT/Triple.h" +#include "llvm/Support/CommandLine.h" using namespace llvm; #define DEBUG_TYPE "wasm-mc-asm-info" +extern cl::opt WasmEnableEH; +extern cl::opt WasmEnableSjLj; + WebAssemblyMCAsmInfo::~WebAssemblyMCAsmInfo() = default; // anchor. WebAssemblyMCAsmInfo::WebAssemblyMCAsmInfo(const Triple &T, @@ -44,5 +48,13 @@ SupportsDebugInformation = true; + // When compilation is done on a cpp file by clang, the exception model info + // is stored in LangOptions, which is later used to set the info in + // TargetOptions and then MCAsmInfo in LLVMTargetMachine::initAsmInfo(). But + // this process does not happen when compiling bitcode directly with clang, so + // we make sure this info is set correctly. + if (WasmEnableEH || WasmEnableSjLj) + ExceptionsType = ExceptionHandling::Wasm; + // TODO: UseIntegratedAssembler? } diff --git a/llvm/lib/Target/WebAssembly/Utils/WebAssemblyUtilities.cpp b/llvm/lib/Target/WebAssembly/Utils/WebAssemblyUtilities.cpp --- a/llvm/lib/Target/WebAssembly/Utils/WebAssemblyUtilities.cpp +++ b/llvm/lib/Target/WebAssembly/Utils/WebAssemblyUtilities.cpp @@ -18,6 +18,29 @@ #include "llvm/MC/MCContext.h" using namespace llvm; +// Exception handling & setjmp-longjmp handling related options. These are +// defined here to be shared between WebAssembly and its subdirectories. + +// Emscripten's asm.js-style exception handling +cl::opt + WasmEnableEmEH("enable-emscripten-cxx-exceptions", + cl::desc("WebAssembly Emscripten-style exception handling"), + cl::init(false)); +// Emscripten's asm.js-style setjmp/longjmp handling +cl::opt WasmEnableEmSjLj( + "enable-emscripten-sjlj", + cl::desc("WebAssembly Emscripten-style setjmp/longjmp handling"), + cl::init(false)); +// Exception handling using wasm EH instructions +cl::opt WasmEnableEH("wasm-enable-eh", + cl::desc("WebAssembly exception handling"), + cl::init(false)); +// setjmp/longjmp handling using wasm EH instrutions +cl::opt WasmEnableSjLj("wasm-enable-sjlj", + cl::desc("WebAssembly setjmp/longjmp handling"), + cl::init(false)); + +// Function names in libc++abi and libunwind const char *const WebAssembly::CxaBeginCatchFn = "__cxa_begin_catch"; const char *const WebAssembly::CxaRethrowFn = "__cxa_rethrow"; const char *const WebAssembly::StdTerminateFn = "_ZSt9terminatev"; diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp --- a/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp +++ b/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp @@ -24,6 +24,7 @@ #include "llvm/CodeGen/RegAllocRegistry.h" #include "llvm/CodeGen/TargetPassConfig.h" #include "llvm/IR/Function.h" +#include "llvm/MC/MCAsmInfo.h" #include "llvm/MC/TargetRegistry.h" #include "llvm/Target/TargetOptions.h" #include "llvm/Transforms/Scalar.h" @@ -33,27 +34,10 @@ #define DEBUG_TYPE "wasm" -// Emscripten's asm.js-style exception handling -cl::opt - WasmEnableEmEH("enable-emscripten-cxx-exceptions", - cl::desc("WebAssembly Emscripten-style exception handling"), - cl::init(false)); - -// Emscripten's asm.js-style setjmp/longjmp handling -cl::opt WasmEnableEmSjLj( - "enable-emscripten-sjlj", - cl::desc("WebAssembly Emscripten-style setjmp/longjmp handling"), - cl::init(false)); - -// Exception handling using wasm EH instructions -cl::opt WasmEnableEH("wasm-enable-eh", - cl::desc("WebAssembly exception handling"), - cl::init(false)); - -// setjmp/longjmp handling using wasm EH instrutions -cl::opt WasmEnableSjLj("wasm-enable-sjlj", - cl::desc("WebAssembly setjmp/longjmp handling"), - cl::init(false)); +extern cl::opt WasmEnableEmEH; // asm.js-style EH +extern cl::opt WasmEnableEmSjLj; // asm.js-style SjLJ +extern cl::opt WasmEnableEH; // EH using Wasm EH instructions +extern cl::opt WasmEnableSjLj; // SjLj using Wasm EH instructions // A command-line option to keep implicit locals // for the purpose of testing with lit/llc ONLY. @@ -368,7 +352,18 @@ return nullptr; // No reg alloc } -static void basicCheckForEHAndSjLj(const TargetMachine *TM) { +static void checkAndSetupForEHAndSjLj(TargetMachine *TM) { + // Before checking, we make sure TargetOptions.ExceptionModel is the same as + // MCAsmInfo.ExceptionsType. Normally when these have to be the same, because + // clang stores the exception model info in LangOptions, which is later + // transferred to TargetOptions and MCAsmInfo. But when clang compiles bitcode + // directly, clang's LangOptions is not used and thus the exception model info + // is not correctly transferred to TargetOptions and MCAsmInfo, so we make + // sure we have the correct exception model in in WebAssemblyMCAsmInfo + // constructor. But in this case TargetOptions is still not updated, so we + // make sure they are the same. + TM->Options.ExceptionModel = TM->getMCAsmInfo()->getExceptionHandlingType(); + // Basic Correctness checking related to -exception-model if (TM->Options.ExceptionModel != ExceptionHandling::None && TM->Options.ExceptionModel != ExceptionHandling::Wasm) @@ -431,7 +426,7 @@ if (getOptLevel() != CodeGenOpt::None) addPass(createWebAssemblyOptimizeReturned()); - basicCheckForEHAndSjLj(TM); + checkAndSetupForEHAndSjLj(TM); // If exception handling is not enabled and setjmp/longjmp handling is // enabled, we lower invokes into calls and delete unreachable landingpad