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[WebAssembly] EmscriptenEHSjLj: Mark __invoke_ functions as imported 

This means the linker will be expect them be undefined at link time an
will generate imports from the `env` module rather than reporting
undefined externals.

Differential Revision: https://reviews.llvm.org/D77192
This commit is contained in:
Sam Clegg 2020-03-31 21:45:57 -07:00
parent f203100ebe
commit 296ccef703
2 changed files with 21 additions and 0 deletions
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17
llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
View File

@ -344,6 +344,21 @@ static std::string getSignature(FunctionType *FTy) {
return Sig;
}
static void markAsImported(Function *F) {
// Tell the linker that this function is expected to be imported from the
// 'env' module.
if (!F->hasFnAttribute("wasm-import-module")) {
llvm::AttrBuilder B;
B.addAttribute("wasm-import-module", "env");
F->addAttributes(llvm::AttributeList::FunctionIndex, B);
}
if (!F->hasFnAttribute("wasm-import-name")) {
llvm::AttrBuilder B;
B.addAttribute("wasm-import-name", F->getName());
F->addAttributes(llvm::AttributeList::FunctionIndex, B);
}
}
// Returns __cxa_find_matching_catch_N function, where N = NumClauses + 2.
// This is because a landingpad instruction contains two more arguments, a
// personality function and a cleanup bit, and __cxa_find_matching_catch_N
@ -360,6 +375,7 @@ WebAssemblyLowerEmscriptenEHSjLj::getFindMatchingCatch(Module &M,
Function *F = Function::Create(
FTy, GlobalValue::ExternalLinkage,
"__cxa_find_matching_catch_" + Twine(NumClauses + 2), &M);
markAsImported(F);
FindMatchingCatches[NumClauses] = F;
return F;
}
@ -469,6 +485,7 @@ Function *WebAssemblyLowerEmscriptenEHSjLj::getInvokeWrapper(CallOrInvoke *CI) {
CalleeFTy->isVarArg());
Function *F =
Function::Create(FTy, GlobalValue::ExternalLinkage, "__invoke_" + Sig, M);
markAsImported(F);
InvokeWrappers[Sig] = F;
return F;
}

4
llvm/test/CodeGen/WebAssembly/lower-em-sjlj.ll
View File

@ -308,6 +308,10 @@ attributes #0 = { returns_twice }
attributes #1 = { noreturn }
attributes #2 = { nounwind }
attributes #3 = { allocsize(0) }
; CHECK: attributes #{{[0-9]+}} = { "wasm-import-module"="env" "wasm-import-name"="__invoke_void" }
; CHECK: attributes #{{[0-9]+}} = { "wasm-import-module"="env" "wasm-import-name"="__cxa_find_matching_catch_3" }
; CHECK: attributes #{{[0-9]+}} = { "wasm-import-module"="env" "wasm-import-name"="__invoke_i8*_i32_%struct.__jmp_buf_tag*" }
; CHECK: attributes #{{[0-9]+}} = { "wasm-import-module"="env" "wasm-import-name"="__invoke_void_%struct.__jmp_buf_tag*_i32" }
; CHECK: attributes #[[ALLOCSIZE_ATTR]] = { allocsize(1) }
!llvm.dbg.cu = !{!2}