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Diffstat (limited to 'lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp')
-rw-r--r--lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp79
1 files changed, 45 insertions, 34 deletions
diff --git a/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp b/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
index 1a416520f97d..b7fc65401fc4 100644
--- a/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
+++ b/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
@@ -1,9 +1,8 @@
//===-- WebAssemblyFixFunctionBitcasts.cpp - Fix function bitcasts --------===//
//
-// The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
///
@@ -36,11 +35,6 @@ using namespace llvm;
#define DEBUG_TYPE "wasm-fix-function-bitcasts"
-static cl::opt<bool>
- TemporaryWorkarounds("wasm-temporary-workarounds",
- cl::desc("Apply certain temporary workarounds"),
- cl::init(true), cl::Hidden);
-
namespace {
class FixFunctionBitcasts final : public ModulePass {
StringRef getPassName() const override {
@@ -70,12 +64,12 @@ ModulePass *llvm::createWebAssemblyFixFunctionBitcasts() {
// Recursively descend the def-use lists from V to find non-bitcast users of
// bitcasts of V.
-static void FindUses(Value *V, Function &F,
+static void findUses(Value *V, Function &F,
SmallVectorImpl<std::pair<Use *, Function *>> &Uses,
SmallPtrSetImpl<Constant *> &ConstantBCs) {
for (Use &U : V->uses()) {
- if (BitCastOperator *BC = dyn_cast<BitCastOperator>(U.getUser()))
- FindUses(BC, F, Uses, ConstantBCs);
+ if (auto *BC = dyn_cast<BitCastOperator>(U.getUser()))
+ findUses(BC, F, Uses, ConstantBCs);
else if (U.get()->getType() != F.getType()) {
CallSite CS(U.getUser());
if (!CS)
@@ -87,8 +81,8 @@ static void FindUses(Value *V, Function &F,
continue;
if (isa<Constant>(U.get())) {
// Only add constant bitcasts to the list once; they get RAUW'd
- auto c = ConstantBCs.insert(cast<Constant>(U.get()));
- if (!c.second)
+ auto C = ConstantBCs.insert(cast<Constant>(U.get()));
+ if (!C.second)
continue;
}
Uses.push_back(std::make_pair(&U, &F));
@@ -119,7 +113,7 @@ static void FindUses(Value *V, Function &F,
// For bitcasts that involve struct types we don't know at this stage if they
// would be equivalent at the wasm level and so we can't know if we need to
// generate a wrapper.
-static Function *CreateWrapper(Function *F, FunctionType *Ty) {
+static Function *createWrapper(Function *F, FunctionType *Ty) {
Module *M = F->getParent();
Function *Wrapper = Function::Create(Ty, Function::PrivateLinkage,
@@ -157,11 +151,11 @@ static Function *CreateWrapper(Function *F, FunctionType *Ty) {
BB->getInstList().push_back(PtrCast);
Args.push_back(PtrCast);
} else if (ArgType->isStructTy() || ParamType->isStructTy()) {
- LLVM_DEBUG(dbgs() << "CreateWrapper: struct param type in bitcast: "
+ LLVM_DEBUG(dbgs() << "createWrapper: struct param type in bitcast: "
<< F->getName() << "\n");
WrapperNeeded = false;
} else {
- LLVM_DEBUG(dbgs() << "CreateWrapper: arg type mismatch calling: "
+ LLVM_DEBUG(dbgs() << "createWrapper: arg type mismatch calling: "
<< F->getName() << "\n");
LLVM_DEBUG(dbgs() << "Arg[" << Args.size() << "] Expected: "
<< *ParamType << " Got: " << *ArgType << "\n");
@@ -197,11 +191,11 @@ static Function *CreateWrapper(Function *F, FunctionType *Ty) {
BB->getInstList().push_back(Cast);
ReturnInst::Create(M->getContext(), Cast, BB);
} else if (RtnType->isStructTy() || ExpectedRtnType->isStructTy()) {
- LLVM_DEBUG(dbgs() << "CreateWrapper: struct return type in bitcast: "
+ LLVM_DEBUG(dbgs() << "createWrapper: struct return type in bitcast: "
<< F->getName() << "\n");
WrapperNeeded = false;
} else {
- LLVM_DEBUG(dbgs() << "CreateWrapper: return type mismatch calling: "
+ LLVM_DEBUG(dbgs() << "createWrapper: return type mismatch calling: "
<< F->getName() << "\n");
LLVM_DEBUG(dbgs() << "Expected: " << *ExpectedRtnType
<< " Got: " << *RtnType << "\n");
@@ -218,15 +212,26 @@ static Function *CreateWrapper(Function *F, FunctionType *Ty) {
new UnreachableInst(M->getContext(), BB);
Wrapper->setName(F->getName() + "_bitcast_invalid");
} else if (!WrapperNeeded) {
- LLVM_DEBUG(dbgs() << "CreateWrapper: no wrapper needed: " << F->getName()
+ LLVM_DEBUG(dbgs() << "createWrapper: no wrapper needed: " << F->getName()
<< "\n");
Wrapper->eraseFromParent();
return nullptr;
}
- LLVM_DEBUG(dbgs() << "CreateWrapper: " << F->getName() << "\n");
+ LLVM_DEBUG(dbgs() << "createWrapper: " << F->getName() << "\n");
return Wrapper;
}
+// Test whether a main function with type FuncTy should be rewritten to have
+// type MainTy.
+static bool shouldFixMainFunction(FunctionType *FuncTy, FunctionType *MainTy) {
+ // Only fix the main function if it's the standard zero-arg form. That way,
+ // the standard cases will work as expected, and users will see signature
+ // mismatches from the linker for non-standard cases.
+ return FuncTy->getReturnType() == MainTy->getReturnType() &&
+ FuncTy->getNumParams() == 0 &&
+ !FuncTy->isVarArg();
+}
+
bool FixFunctionBitcasts::runOnModule(Module &M) {
LLVM_DEBUG(dbgs() << "********** Fix Function Bitcasts **********\n");
@@ -237,27 +242,27 @@ bool FixFunctionBitcasts::runOnModule(Module &M) {
// Collect all the places that need wrappers.
for (Function &F : M) {
- FindUses(&F, F, Uses, ConstantBCs);
+ findUses(&F, F, Uses, ConstantBCs);
// If we have a "main" function, and its type isn't
// "int main(int argc, char *argv[])", create an artificial call with it
// bitcasted to that type so that we generate a wrapper for it, so that
// the C runtime can call it.
- if (!TemporaryWorkarounds && !F.isDeclaration() && F.getName() == "main") {
+ if (F.getName() == "main") {
Main = &F;
LLVMContext &C = M.getContext();
Type *MainArgTys[] = {Type::getInt32Ty(C),
PointerType::get(Type::getInt8PtrTy(C), 0)};
FunctionType *MainTy = FunctionType::get(Type::getInt32Ty(C), MainArgTys,
/*isVarArg=*/false);
- if (F.getFunctionType() != MainTy) {
+ if (shouldFixMainFunction(F.getFunctionType(), MainTy)) {
LLVM_DEBUG(dbgs() << "Found `main` function with incorrect type: "
<< *F.getFunctionType() << "\n");
Value *Args[] = {UndefValue::get(MainArgTys[0]),
UndefValue::get(MainArgTys[1])};
Value *Casted =
ConstantExpr::getBitCast(Main, PointerType::get(MainTy, 0));
- CallMain = CallInst::Create(Casted, Args, "call_main");
+ CallMain = CallInst::Create(MainTy, Casted, Args, "call_main");
Use *UseMain = &CallMain->getOperandUse(2);
Uses.push_back(std::make_pair(UseMain, &F));
}
@@ -269,8 +274,8 @@ bool FixFunctionBitcasts::runOnModule(Module &M) {
for (auto &UseFunc : Uses) {
Use *U = UseFunc.first;
Function *F = UseFunc.second;
- PointerType *PTy = cast<PointerType>(U->get()->getType());
- FunctionType *Ty = dyn_cast<FunctionType>(PTy->getElementType());
+ auto *PTy = cast<PointerType>(U->get()->getType());
+ auto *Ty = dyn_cast<FunctionType>(PTy->getElementType());
// If the function is casted to something like i8* as a "generic pointer"
// to be later casted to something else, we can't generate a wrapper for it.
@@ -280,7 +285,7 @@ bool FixFunctionBitcasts::runOnModule(Module &M) {
auto Pair = Wrappers.insert(std::make_pair(std::make_pair(F, Ty), nullptr));
if (Pair.second)
- Pair.first->second = CreateWrapper(F, Ty);
+ Pair.first->second = createWrapper(F, Ty);
Function *Wrapper = Pair.first->second;
if (!Wrapper)
@@ -296,14 +301,20 @@ bool FixFunctionBitcasts::runOnModule(Module &M) {
// one that gets called from startup.
if (CallMain) {
Main->setName("__original_main");
- Function *MainWrapper =
+ auto *MainWrapper =
cast<Function>(CallMain->getCalledValue()->stripPointerCasts());
- MainWrapper->setName("main");
- MainWrapper->setLinkage(Main->getLinkage());
- MainWrapper->setVisibility(Main->getVisibility());
- Main->setLinkage(Function::PrivateLinkage);
- Main->setVisibility(Function::DefaultVisibility);
delete CallMain;
+ if (Main->isDeclaration()) {
+ // The wrapper is not needed in this case as we don't need to export
+ // it to anyone else.
+ MainWrapper->eraseFromParent();
+ } else {
+ // Otherwise give the wrapper the same linkage as the original main
+ // function, so that it can be called from the same places.
+ MainWrapper->setName("main");
+ MainWrapper->setLinkage(Main->getLinkage());
+ MainWrapper->setVisibility(Main->getVisibility());
+ }
}
return true;
generated by cgit v1.2.3 (git 2.25.1) at 2025-08-07 13:12:31 +0000