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[WebAssembly] Don't inline -emscripten-cxx-exceptions-allowed functions

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Functions specified in `-emscripten-cxx-exceptions-allowed`, which is
set by Emscripten's `EXCEPTION_CATCHING_ALLOWED` setting, can be inlined
in LLVM middle ends before we reach WebAssemblyLowerEmscriptenEHSjLj
pass in the wasm backend and thus don't get transformed for exception
catching.

This fixes the issue by adding `--force-attribute=FUNC_NAME:noinline`
for each function name in `-emscripten-cxx-exceptions-allowed`, which
adds `noinline` attribute to the specified function and thus excludes
the function from inlining candidates in optimization passes.

Fixes the remaining half of
https://github.com/emscripten-core/emscripten/issues/10721.

Reviewed By: sbc100

Differential Revision: https://reviews.llvm.org/D99259
This commit is contained in:
Heejin Ahn 2021-03-24 06:06:58 -07:00
parent 9d45579279
commit a6aae5f7fc
2 changed files with 45 additions and 0 deletions
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30
clang/lib/Driver/ToolChains/WebAssembly.cpp
View File

@ -294,6 +294,36 @@ void WebAssembly::addClangTargetOptions(const ArgList &DriverArgs,
CC1Args.push_back("-target-feature");
CC1Args.push_back("+exception-handling");
}
for (const Arg *A : DriverArgs.filtered(options::OPT_mllvm)) {
StringRef Opt = A->getValue(0);
if (Opt.startswith("-emscripten-cxx-exceptions-allowed")) {
// '-mllvm -emscripten-cxx-exceptions-allowed' should be used with
// '-mllvm -enable-emscripten-cxx-exceptions'
bool EmExceptionArgExists = false;
for (const Arg *A : DriverArgs.filtered(options::OPT_mllvm)) {
if (StringRef(A->getValue(0)) == "-enable-emscripten-cxx-exceptions") {
EmExceptionArgExists = true;
break;
}
}
if (!EmExceptionArgExists)
getDriver().Diag(diag::err_drv_argument_only_allowed_with)
<< "-mllvm -emscripten-cxx-exceptions-allowed"
<< "-mllvm -enable-emscripten-cxx-exceptions";
// Prevent functions specified in -emscripten-cxx-exceptions-allowed list
// from being inlined before reaching the wasm backend.
StringRef FuncNamesStr = Opt.split('=').second;
SmallVector<StringRef, 4> FuncNames;
FuncNamesStr.split(FuncNames, ',');
for (auto Name : FuncNames) {
CC1Args.push_back("-mllvm");
CC1Args.push_back(DriverArgs.MakeArgString("--force-attribute=" + Name +
":noinline"));
}
}
}
}
ToolChain::RuntimeLibType WebAssembly::GetDefaultRuntimeLibType() const {

15
clang/test/Driver/wasm-toolchain.c
View File

@ -79,6 +79,21 @@
// RUN: | FileCheck -check-prefix=PTHREAD_NO_SIGN_EXT %s
// PTHREAD_NO_SIGN_EXT: invalid argument '-pthread' not allowed with '-mno-sign-ext'
// '-mllvm -emscripten-cxx-exceptions-allowed=foo,bar' sets
// '-mllvm --force-attribute=foo:noinline -mllvm --force-attribute=bar:noinline'
// RUN: %clang -### -no-canonical-prefixes -target wasm32-unknown-unknown \
// RUN: --sysroot=/foo %s -mllvm -enable-emscripten-cxx-exceptions \
// RUN: -mllvm -emscripten-cxx-exceptions-allowed=foo,bar 2>&1 \
// RUN: | FileCheck -check-prefix=EMSCRIPTEN_EH_ALLOWED_NOINLINE %s
// EMSCRIPTEN_EH_ALLOWED_NOINLINE: clang{{.*}}" "-cc1" {{.*}} "-mllvm" "--force-attribute=foo:noinline" "-mllvm" "--force-attribute=bar:noinline"
// '-mllvm -emscripten-cxx-exceptions-allowed' only allowed with
// '-mllvm -enable-emscripten-cxx-exceptions'
// RUN: %clang -### -no-canonical-prefixes -target wasm32-unknown-unknown \
// RUN: --sysroot=/foo %s -mllvm -emscripten-cxx-exceptions-allowed 2>&1 \
// RUN: | FileCheck -check-prefix=EMSCRIPTEN_EH_ALLOWED_WO_ENABLE %s
// EMSCRIPTEN_EH_ALLOWED_WO_ENABLE: invalid argument '-mllvm -emscripten-cxx-exceptions-allowed' only allowed with '-mllvm -enable-emscripten-cxx-exceptions'
// '-fwasm-exceptions' sets +exception-handling
// RUN: %clang -### -no-canonical-prefixes -target wasm32-unknown-unknown \
// RUN: --sysroot=/foo %s -fwasm-exceptions 2>&1 \