[WebAssembly] Support bitcasted function addresses with varargs.
Generalize FixFunctionBitcasts to handle varargs functions. This in
particular fixes the case where clang bitcasts away a varargs when
calling a K&R-style function.
This avoids interacting with tricky ABI details because it operates
at the LLVM IR level before varargs ABI details are exposed.
This fixes PR35385.
llvm-svn: 319186
diff --git a/llvm/lib/MC/WasmObjectWriter.cpp b/llvm/lib/MC/WasmObjectWriter.cpp
index 2297084..6e9088b 100644
--- a/llvm/lib/MC/WasmObjectWriter.cpp
+++ b/llvm/lib/MC/WasmObjectWriter.cpp
@@ -1040,12 +1040,15 @@
for (const MCSymbol &S : Asm.symbols()) {
const auto &WS = static_cast<const MCSymbolWasm &>(S);
- if (WS.isTemporary())
- continue;
-
+ // Register types for all functions, including those with private linkage
+ // (making them
+ // because wasm always needs a type signature.
if (WS.isFunction())
registerFunctionType(WS);
+ if (WS.isTemporary())
+ continue;
+
// If the symbol is not defined in this translation unit, import it.
if (!WS.isDefined(/*SetUsed=*/false)) {
WasmImport Import;
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
index 19df75c..6473a2b 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
@@ -107,9 +107,10 @@
// Determine what arguments to pass.
SmallVector<Value *, 4> Args;
Function::arg_iterator AI = Wrapper->arg_begin();
+ Function::arg_iterator AE = Wrapper->arg_end();
FunctionType::param_iterator PI = F->getFunctionType()->param_begin();
FunctionType::param_iterator PE = F->getFunctionType()->param_end();
- for (; AI != Wrapper->arg_end() && PI != PE; ++AI, ++PI) {
+ for (; AI != AE && PI != PE; ++AI, ++PI) {
if (AI->getType() != *PI) {
Wrapper->eraseFromParent();
return nullptr;
@@ -118,6 +119,9 @@
}
for (; PI != PE; ++PI)
Args.push_back(UndefValue::get(*PI));
+ if (F->isVarArg())
+ for (; AI != AE; ++AI)
+ Args.push_back(&*AI);
CallInst *Call = CallInst::Create(F, Args, "", BB);
@@ -158,11 +162,6 @@
if (!Ty)
continue;
- // Wasm varargs are not ABI-compatible with non-varargs. Just ignore
- // such casts for now.
- if (Ty->isVarArg() || F->isVarArg())
- continue;
-
auto Pair = Wrappers.insert(std::make_pair(std::make_pair(F, Ty), nullptr));
if (Pair.second)
Pair.first->second = CreateWrapper(F, Ty);