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feat: rework cheerp_allocate & co
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cheerp_allocate and related functions had a few issues, in particular
they were not used consistently and so a lot of edge cases existed.

On top of that, for Wasm we would lose the information about the
original allocation/deallocation function called, and we defaulted to
malloc/free. This meant that, for example, overriding the global
new/delete would not have any effect.

The new rules are: we ALWAYS use cheerp_allocate & co. For Wasm, we also
include as first parameter the original function. We also do it for
deallocation in genericjs when the argument might have come from linear
memory.

Then in GDA in llc we replace with the original function, is present.

All the other changes are just minor consequences of this new system.
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@DutChen18 @yuri91
DutChen18 authored and yuri91 committed Dec 16, 2024
1 parent 2f11369 commit 465ac16
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Showing 26 changed files with 426 additions and 690 deletions.
1 change: 1 addition & 0 deletions clang/include/clang/Basic/BuiltinsCheerp.def
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Original file line number Diff line number Diff line change
Expand Up @@ -34,6 +34,7 @@ BUILTIN(__builtin_cheerp_throw, "", "rB")
BUILTIN(__builtin_cheerp_downcast, "", "B")
BUILTIN(__builtin_cheerp_downcast_current, "", "B")
BUILTIN(__builtin_cheerp_coro_alloc, "v*z", "n")
BUILTIN(__builtin_cheerp_deallocate, "vv*", "n")
BUILTIN(__builtin_cheerp_environ, "vC*", "B")
BUILTIN(__builtin_cheerp_argv, "vC*", "B")
BUILTIN(__builtin_cheerp_get_threading_object, "", "B")
Expand Down
167 changes: 85 additions & 82 deletions clang/lib/CodeGen/CGBuiltin.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3421,22 +3421,15 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
llvm::Type *Tys[] = { VoidPtrTy, VoidPtrTy };
const CastExpr* retCE=dyn_cast_or_null<CastExpr>(parent);
llvm::Type *elementType = nullptr;
if (!retCE || retCE->getType()->isVoidPointerType())
if (!retCE || retCE->getType()->isVoidPointerType()) {
CGM.getDiags().Report(E->getBeginLoc(), diag::err_cheerp_alloc_requires_cast);
else
{
QualType returnType=retCE->getType();
Tys[0] = Tys[1] = ConvertType(returnType);
elementType = ConvertType(returnType->getPointeeType());
} else {
QualType returnType=retCE->getType();
Tys[0] = ConvertType(returnType);
elementType = ConvertType(returnType->getPointeeType());
CallBase* CB = cheerp::createCheerpAllocate(Builder, nullptr, elementType, Size);
return RValue::get(CB);
}
Function *F = CGM.getIntrinsic(Intrinsic::cheerp_allocate, Tys);
CallBase* CB = Builder.CreateCall(F, {llvm::Constant::getNullValue(Tys[0]),Size});

assert(elementType);
assert(Tys[0]->isOpaquePointerTy() || Tys[0]->getNonOpaquePointerElementType() == elementType);

CB->addParamAttr(0, llvm::Attribute::get(CB->getContext(), llvm::Attribute::ElementType, elementType));
return RValue::get(CB);
}
const TargetInfo &TI = getContext().getTargetInfo();
// The alignment of the alloca should correspond to __BIGGEST_ALIGNMENT__.
Expand Down Expand Up @@ -12553,6 +12546,13 @@ Value *CodeGenFunction::EmitCheerpBuiltinExpr(unsigned BuiltinID,
Function *F = CGM.getIntrinsic(Intrinsic::cheerp_coro_alloc);
return EmitCallOrInvoke(F, Ops);
}
else if (BuiltinID == Cheerp::BI__builtin_cheerp_deallocate) {
// This is only used in SemaCoroutine, so we just care for the genericjs
// case, and for now only void* argument
llvm::Type *Tys[] = { VoidPtrTy, Ops[0]->getType() };
Function *F = CGM.getIntrinsic(Intrinsic::cheerp_deallocate, Tys);
return EmitCallOrInvoke(F, {ConstantPointerNull::get(VoidPtrTy), Ops[0]});
}
else if (BuiltinID == Cheerp::BI__builtin_cheerp_throw) {
llvm::Type *Tys[] = { Ops[0]->getType() };
Function *F = CGM.getIntrinsic(Intrinsic::cheerp_throw, Tys);
Expand Down Expand Up @@ -12686,24 +12686,22 @@ Value *CodeGenFunction::EmitCheerpBuiltinExpr(unsigned BuiltinID,
// We need an explicit cast after the call, void* can't be used
llvm::Type *Tys[] = { VoidPtrTy, VoidPtrTy };
const CastExpr* retCE=dyn_cast_or_null<CastExpr>(parent);
if (!retCE || retCE->getType()->isVoidPointerType())
{
if (!asmjs)
CGM.getDiags().Report(E->getBeginLoc(), diag::err_cheerp_alloc_requires_cast);
llvm::Type* elementType = nullptr;
if (!retCE || retCE->getType()->isVoidPointerType()) {
if (!asmjs) {
CGM.getDiags().Report(E->getBeginLoc(), diag::err_cheerp_alloc_requires_cast);
return 0;
}
} else {
elementType = ConvertTypeForMem(retCE->getType()->getPointeeType());
Tys[0] = ConvertType(retCE->getType());
}
else
{
QualType returnType=retCE->getType();
Tys[0] = Tys[1] = ConvertType(returnType);
llvm::Function* Malloc = nullptr;
// in Wasm, we pass the original allocation function as argument 0
if (asmjs || (elementType->isStructTy() && cast<llvm::StructType>(elementType)->hasAsmJS())) {
Malloc = dyn_cast<Function>(CGM.getModule().getOrInsertFunction("malloc", Int8PtrTy, Int32Ty).getCallee());
}
Function *F = CGM.getIntrinsic(Intrinsic::cheerp_allocate, Tys);
CallBase* CB = Builder.CreateCall(F, {llvm::Constant::getNullValue(Tys[0]), Ops[0]});

llvm::Type* elementType = ConvertTypeForMem(retCE->getType()->getPointeeType());
assert(Tys[0]->isOpaquePointerTy() || Tys[0]->getNonOpaquePointerElementType() == elementType);

CB->addParamAttr(0, llvm::Attribute::get(CB->getContext(), llvm::Attribute::ElementType, elementType));
llvm::CallBase* CB = cheerp::createCheerpAllocate(Builder, Malloc, elementType, Ops[0]);
return CB;
}
else if (BuiltinID == Builtin::BIcalloc) {
Expand All @@ -12714,48 +12712,45 @@ Value *CodeGenFunction::EmitCheerpBuiltinExpr(unsigned BuiltinID,
ParentMap PM(FD ? FD->getBody() : const_cast<Expr*>(VD->getInit()));
const Stmt* parent=PM.getParent(E);
// We need an explicit cast after the call, void* can't be used
llvm::Type *Tys[] = { VoidPtrTy , VoidPtrTy};
const CastExpr* retCE=dyn_cast_or_null<CastExpr>(parent);
if (!retCE || retCE->getType()->isVoidPointerType())
{
if (!asmjs)
CGM.getDiags().Report(E->getBeginLoc(), diag::err_cheerp_alloc_requires_cast);
llvm::Type* elementType = nullptr;
if (!retCE || retCE->getType()->isVoidPointerType()) {
if (!asmjs) {
CGM.getDiags().Report(E->getBeginLoc(), diag::err_cheerp_alloc_requires_cast);
return 0;
}
} else {
elementType = ConvertTypeForMem(retCE->getType()->getPointeeType());
}
else
{
QualType returnType=retCE->getType();
Tys[0] = Tys[1] = ConvertType(returnType);
llvm::Function* Malloc = nullptr;
// in Wasm, we pass the original allocation function as argument 0
// in this case malloc and not calloc since we explicitly memset after
if (asmjs || (elementType->isStructTy() && cast<llvm::StructType>(elementType)->hasAsmJS())) {
Malloc = dyn_cast<llvm::Function>(CGM.getModule().getOrInsertFunction("malloc", Int8PtrTy, Int32Ty).getCallee());
}
Function *F = CGM.getIntrinsic(Intrinsic::cheerp_allocate, Tys);
// Compute the size in bytes
llvm::Value* sizeInBytes = Builder.CreateMul(Ops[0], Ops[1]);
llvm::Value* NewOp[2] = { llvm::Constant::getNullValue(Tys[0]), sizeInBytes };
llvm::CallBase* Ret = Builder.CreateCall(F, NewOp);

llvm::Type* elementType = ConvertTypeForMem(retCE->getType()->getPointeeType());
assert(Tys[0]->isOpaquePointerTy() || Tys[0]->getNonOpaquePointerElementType() == elementType);

Ret->addParamAttr(0, llvm::Attribute::get(Ret->getContext(), llvm::Attribute::ElementType, elementType));
Builder.CreateMemSet(Ret, ConstantInt::get(Int8Ty, 0), sizeInBytes, MaybeAlign(1), false, NULL, NULL, NULL,
CGBuilderTy::CheerpTypeInfo::get(getTarget().isByteAddressable(), ConvertType(retCE->getType()->getPointeeType())));
return Ret;
llvm::CallBase* CB = cheerp::createCheerpAllocate(Builder, Malloc, elementType, sizeInBytes);
Builder.CreateMemSet(CB, ConstantInt::get(Int8Ty, 0), sizeInBytes, MaybeAlign(1), false, NULL, NULL, NULL,
CGBuilderTy::CheerpTypeInfo::get(getTarget().isByteAddressable(), elementType));
return CB;
}
else if (BuiltinID == Builtin::BIrealloc) {
// There must be an incoming cast, void* are not directly accepted
const CastExpr* argCE=dyn_cast<CastExpr>(E->getArg(0));
const Expr* existingMem = E->getArg(0);
const CastExpr* argCE=dyn_cast<CastExpr>(existingMem);

if (!argCE || argCE->getSubExpr()->getType()->isVoidPointerType()) {
if (!asmjs)
if ((!argCE || argCE->getSubExpr()->getType()->isVoidPointerType())) {
if (!asmjs) {
CGM.getDiags().Report(E->getArg(0)->getBeginLoc(), diag::err_cheerp_memintrinsic_type_unknown);
return 0;
return 0;
}
} else {
existingMem = argCE->getSubExpr();
}

//TODO: realloc can be invoked with NULL, support that
const Expr* existingMem=argCE->getSubExpr();
// The type for the realloc is decided from the base type
QualType reallocType=existingMem->getType();
llvm::Type *Tys[] = { VoidPtrTy, ConvertType(reallocType) };
Ops[0]=EmitScalarExpr(existingMem);
// Some additional checks that can't be done in Sema
const FunctionDecl* FD=dyn_cast_if_present<FunctionDecl>(CurFuncDecl);
Expand All @@ -12766,29 +12761,32 @@ Value *CodeGenFunction::EmitCheerpBuiltinExpr(unsigned BuiltinID,
const Stmt* parent=PM.getParent(E);
// We need an explicit cast after the call, void* can't be used
const CastExpr* retCE=dyn_cast_or_null<CastExpr>(parent);
if (!retCE || retCE->getType()->isVoidPointerType())
llvm::Type* elementType = nullptr;
if ((!retCE || retCE->getType()->isVoidPointerType()))
{
if (!asmjs)
if (!asmjs) {
CGM.getDiags().Report(E->getBeginLoc(), diag::err_cheerp_alloc_requires_cast);
return 0;
return 0;
}
}
else if(retCE->getType().getCanonicalType()!=reallocType.getCanonicalType())
{
if (asmjs) return 0;
CGM.getDiags().Report(E->getBeginLoc(), diag::err_cheerp_realloc_different_types);
if (!asmjs) {
CGM.getDiags().Report(E->getBeginLoc(), diag::err_cheerp_realloc_different_types);
return 0;
}
}
else {
// The call is fully valid, so set the return type to the existing type
Tys[0]=Tys[1];
elementType = ConvertTypeForMem(reallocType->getPointeeType());
}

llvm::Type* elementType = ConvertTypeForMem(reallocType->getPointeeType());
assert(Tys[0]->isOpaquePointerTy() || Tys[0]->getNonOpaquePointerElementType() == elementType);

Function *reallocFunc = CGM.getIntrinsic(Intrinsic::cheerp_reallocate, Tys);
if(asmjs) {
CallBase* CB = Builder.CreateCall(reallocFunc, Ops);
CB->addParamAttr(0, llvm::Attribute::get(CB->getContext(), llvm::Attribute::ElementType, elementType));
llvm::Type *RetTy = Builder.getInt8PtrTy();
llvm::Type *Arg0Ty = Builder.getInt8PtrTy();
llvm::Type *Arg1Ty = Builder.getInt32Ty();
llvm::Function* origReallocFunc = dyn_cast<llvm::Function>(CGM.getModule().getOrInsertFunction("realloc", RetTy, Arg0Ty, Arg1Ty).getCallee());
CallBase* CB = cheerp::createCheerpReallocate(Builder, origReallocFunc, elementType, Ops[0], Ops[1]);
return CB;
} else {
// realloc needs to behave like malloc if the operand is null
Expand All @@ -12799,32 +12797,37 @@ Value *CodeGenFunction::EmitCheerpBuiltinExpr(unsigned BuiltinID,
Builder.CreateCondBr(opIsNull, mallocBlock, reallocBlock);
Builder.SetInsertPoint(mallocBlock);

Function *mallocFunc = CGM.getIntrinsic(Intrinsic::cheerp_allocate, Tys);
llvm::CallBase* mallocRet = Builder.CreateCall(mallocFunc, {llvm::Constant::getNullValue(Tys[0]), Ops[1]});
mallocRet->addParamAttr(0, llvm::Attribute::get(mallocRet->getContext(), llvm::Attribute::ElementType, elementType));
CallBase* mallocRet = cheerp::createCheerpAllocate(Builder, nullptr, elementType, Ops[1]);
Builder.CreateBr(endBlock);
Builder.SetInsertPoint(reallocBlock);
llvm::CallBase* reallocRet = cast<CallBase>(Builder.CreateCall(reallocFunc, Ops));
reallocRet->addParamAttr(0, llvm::Attribute::get(reallocRet->getContext(), llvm::Attribute::ElementType, elementType));
CallBase* reallocRet = cheerp::createCheerpReallocate(Builder, nullptr, elementType, Ops[0], Ops[1]);
Builder.CreateBr(endBlock);
Builder.SetInsertPoint(endBlock);
llvm::PHINode* Result = Builder.CreatePHI(Tys[0], 2);
llvm::PHINode* Result = Builder.CreatePHI(mallocRet->getType(), 2);
Result->addIncoming(mallocRet, mallocBlock);
Result->addIncoming(reallocRet, reallocBlock);
return Result;
}
}
else if (BuiltinID == Builtin::BIfree) {
llvm::Value* origArg = Ops[0];
llvm::Type* origType = origArg->getType();
if (CallInst* CI = dyn_cast<CallInst>(Ops[0])) {
if (auto* c = dyn_cast<CastExpr>(E->getArg(0))) {
origArg = CI->getOperand(0);
origType = origArg->getType();
const CastExpr* argCE=dyn_cast<CastExpr>(E->getArg(0));
llvm::Type* elementType = nullptr;
if (argCE) {
QualType ptrTy = argCE->getSubExpr()->getType();
if (ptrTy->isPointerType() && !ptrTy->isVoidPointerType()) {
elementType = ConvertType(ptrTy->getPointeeType());
Ops[0]=EmitScalarExpr(argCE->getSubExpr());
}
}
Function *F = CGM.getIntrinsic(Intrinsic::cheerp_deallocate, {origType});
return Builder.CreateCall(F, origArg);
llvm::Function* Free = nullptr;
// in Wasm, we pass the original deallocation function as argument 0
// For free, we always pass this argument unless the element type is a genericjs struct,
// because the pointer may have come from Wasm originally
if (asmjs || (elementType && elementType->isStructTy() && !cast<llvm::StructType>(elementType)->hasAsmJS())) {
Free = dyn_cast<llvm::Function>(CGM.getModule().getOrInsertFunction("free", VoidTy, Int8PtrTy).getCallee());
}
llvm::CallBase* CB = cheerp::createCheerpDeallocate(Builder, Free, elementType, Ops[0]);
return CB;
}
return 0;
}
Expand Down
11 changes: 3 additions & 8 deletions clang/lib/CodeGen/CGDecl.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,7 @@
#include "clang/CodeGen/CGFunctionInfo.h"
#include "clang/Sema/Sema.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/Cheerp/Utility.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/Intrinsics.h"
Expand Down Expand Up @@ -1602,15 +1603,9 @@ CodeGenFunction::EmitAutoVarAlloca(const VarDecl &D) {
llvm::Type *llvmTy = ConvertTypeForMem(elementType);
uint64_t size = CGM.getDataLayout().getTypeAllocSize(llvmTy);
llvm::Constant* typeSize = llvm::ConstantInt::get(elementCount->getType(), size);

llvm::Type* Tys[] = { llvmTy->getPointerTo(), llvmTy->getPointerTo() };
llvm::Function *F = CGM.getIntrinsic(llvm::Intrinsic::cheerp_allocate, Tys);
// Compute the size in bytes
llvm::Value* sizeInBytes = Builder.CreateMul(elementCount, typeSize);
llvm::Value* Args[2] = { llvm::Constant::getNullValue(llvmTy->getPointerTo()), sizeInBytes };
// Allocate memory for the array.
llvm::Value* Ret = Builder.CreateCall(F, Args);
cast<llvm::CallInst>(Ret)->addParamAttr(0, llvm::Attribute::get(Ret->getContext(), llvm::Attribute::ElementType, llvmTy));

llvm::Value* Ret = cheerp::createCheerpAllocate(Builder, nullptr, llvmTy, sizeInBytes);
address = Address(Ret, llvmTy, CharUnits::One());
} else {
EnsureInsertPoint();
Expand Down
30 changes: 17 additions & 13 deletions clang/lib/CodeGen/CGException.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@
#include "clang/AST/StmtVisitor.h"
#include "clang/Basic/DiagnosticSema.h"
#include "clang/Basic/TargetBuiltins.h"
#include "llvm/Cheerp/Utility.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/IntrinsicsWebAssembly.h"
Expand All @@ -30,21 +31,13 @@
using namespace clang;
using namespace CodeGen;

static llvm::FunctionCallee getFreeExceptionFn(CodeGenModule &CGM, llvm::Type* t) {
static llvm::FunctionCallee getFreeExceptionFn(CodeGenModule &CGM) {
// void __cxa_free_exception(void *thrown_exception);

if(CGM.getTarget().isByteAddressable()) {
llvm::FunctionType *FTy =
llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*isVarArg=*/false);
llvm::FunctionType *FTy =
llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*isVarArg=*/false);

return CGM.CreateRuntimeFunction(FTy, "__cxa_free_exception");
}
else {
llvm::Type* types[] = { t };
llvm::Function* F = llvm::Intrinsic::getDeclaration(&CGM.getModule(),
llvm::Intrinsic::cheerp_deallocate, types);
return llvm::FunctionCallee(F->getFunctionType(), F);
}
return CGM.CreateRuntimeFunction(FTy, "__cxa_free_exception");
}

static llvm::FunctionCallee getSehTryBeginFn(CodeGenModule &CGM) {
Expand Down Expand Up @@ -399,7 +392,18 @@ namespace {
llvm::Value *exn;
FreeException(llvm::Value *exn) : exn(exn) {}
void Emit(CodeGenFunction &CGF, Flags flags) override {
CGF.EmitNounwindRuntimeCall(getFreeExceptionFn(CGF.CGM, exn->getType()), exn);
if (CGF.getLangOpts().Cheerp) {
llvm::Function* origFunc = nullptr;
if (CGF.getTarget().getTriple().isCheerpWasm()) {
llvm::FunctionType *FreeTy =
llvm::FunctionType::get(CGF.VoidTy, CGF.VoidPtrTy, /*isVarArg=*/false);

origFunc = cast<llvm::Function>(CGF.CGM.CreateRuntimeFunction(FreeTy, "free").getCallee());
}
cheerp::createCheerpDeallocate(CGF.Builder, origFunc, nullptr, exn);
} else {
CGF.EmitNounwindRuntimeCall(getFreeExceptionFn(CGF.CGM), exn);
}
}
};
} // end anonymous namespace
Expand Down
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