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[CIR][CIRGen][NFC] Enhance alloca helpers (llvm#367)
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One more step towards variable length array support. 
This PR adds one more helper for the `alloca` instruction and re-use the
existing ones.

The reason is the following: right now there are two possible ways to
insert alloca: either to a function entry block or to the given block
after all the existing alloca instructions. But for VLA support we need
to insert alloca anywhere, right after an array's size becomes known.
Thus, we add one more parameter with the default value - insertion
point.

Also, we don't want copy-paste the code, and reuse the existing helpers,
but it may be a little bit confusing to read.
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@gitoleg @lanza
gitoleg authored and lanza committed Jan 29, 2024
1 parent 043aa75 commit 9bcfc1a
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Showing 2 changed files with 44 additions and 22 deletions.
47 changes: 30 additions & 17 deletions clang/lib/CIR/CodeGen/CIRGenExpr.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2286,17 +2286,19 @@ mlir::Value CIRGenFunction::buildOpOnBoolExpr(const Expr *cond,

mlir::Value CIRGenFunction::buildAlloca(StringRef name, mlir::Type ty,
mlir::Location loc, CharUnits alignment,
bool insertIntoFnEntryBlock) {
bool insertIntoFnEntryBlock,
mlir::Value arraySize) {
mlir::Block *entryBlock = insertIntoFnEntryBlock
? getCurFunctionEntryBlock()
: currLexScope->getEntryBlock();
return buildAlloca(name, ty, loc, alignment,
builder.getBestAllocaInsertPoint(entryBlock));
builder.getBestAllocaInsertPoint(entryBlock), arraySize);
}

mlir::Value CIRGenFunction::buildAlloca(StringRef name, mlir::Type ty,
mlir::Location loc, CharUnits alignment,
mlir::OpBuilder::InsertPoint ip) {
mlir::OpBuilder::InsertPoint ip,
mlir::Value arraySize) {
auto localVarPtrTy = mlir::cir::PointerType::get(builder.getContext(), ty);
auto alignIntAttr = CGM.getSize(alignment);

Expand All @@ -2306,7 +2308,7 @@ mlir::Value CIRGenFunction::buildAlloca(StringRef name, mlir::Type ty,
builder.restoreInsertionPoint(ip);
addr = builder.create<mlir::cir::AllocaOp>(loc, /*addr type*/ localVarPtrTy,
/*var type*/ ty, name,
alignIntAttr);
alignIntAttr, arraySize);
if (currVarDecl) {
auto alloca = cast<mlir::cir::AllocaOp>(addr.getDefiningOp());
alloca.setAstAttr(ASTVarDeclAttr::get(builder.getContext(), currVarDecl));
Expand All @@ -2317,9 +2319,10 @@ mlir::Value CIRGenFunction::buildAlloca(StringRef name, mlir::Type ty,

mlir::Value CIRGenFunction::buildAlloca(StringRef name, QualType ty,
mlir::Location loc, CharUnits alignment,
bool insertIntoFnEntryBlock) {
bool insertIntoFnEntryBlock,
mlir::Value arraySize) {
return buildAlloca(name, getCIRType(ty), loc, alignment,
insertIntoFnEntryBlock);
insertIntoFnEntryBlock, arraySize);
}

mlir::Value CIRGenFunction::buildLoadOfScalar(LValue lvalue,
Expand Down Expand Up @@ -2467,12 +2470,11 @@ Address CIRGenFunction::CreateMemTemp(QualType Ty, CharUnits Align,

/// This creates a alloca and inserts it into the entry block of the
/// current region.
Address CIRGenFunction::CreateTempAllocaWithoutCast(mlir::Type Ty,
CharUnits Align,
mlir::Location Loc,
const Twine &Name,
mlir::Value ArraySize) {
auto Alloca = CreateTempAlloca(Ty, Loc, Name, ArraySize);
Address CIRGenFunction::CreateTempAllocaWithoutCast(
mlir::Type Ty, CharUnits Align, mlir::Location Loc, const Twine &Name,
mlir::Value ArraySize, mlir::OpBuilder::InsertPoint ip) {
auto Alloca = ip.isSet() ? CreateTempAlloca(Ty, Loc, Name, ip, ArraySize)
: CreateTempAlloca(Ty, Loc, Name, ArraySize);
Alloca.setAlignmentAttr(CGM.getSize(Align));
return Address(Alloca, Ty, Align);
}
Expand All @@ -2482,8 +2484,10 @@ Address CIRGenFunction::CreateTempAllocaWithoutCast(mlir::Type Ty,
Address CIRGenFunction::CreateTempAlloca(mlir::Type Ty, CharUnits Align,
mlir::Location Loc, const Twine &Name,
mlir::Value ArraySize,
Address *AllocaAddr) {
auto Alloca = CreateTempAllocaWithoutCast(Ty, Align, Loc, Name, ArraySize);
Address *AllocaAddr,
mlir::OpBuilder::InsertPoint ip) {
auto Alloca =
CreateTempAllocaWithoutCast(Ty, Align, Loc, Name, ArraySize, ip);
if (AllocaAddr)
*AllocaAddr = Alloca;
mlir::Value V = Alloca.getPointer();
Expand All @@ -2502,10 +2506,19 @@ mlir::cir::AllocaOp
CIRGenFunction::CreateTempAlloca(mlir::Type Ty, mlir::Location Loc,
const Twine &Name, mlir::Value ArraySize,
bool insertIntoFnEntryBlock) {
if (ArraySize)
assert(0 && "NYI");
return cast<mlir::cir::AllocaOp>(buildAlloca(Name.str(), Ty, Loc, CharUnits(),
insertIntoFnEntryBlock,
ArraySize)
.getDefiningOp());
}

/// This creates an alloca and inserts it into the provided insertion point
mlir::cir::AllocaOp CIRGenFunction::CreateTempAlloca(
mlir::Type Ty, mlir::Location Loc, const Twine &Name,
mlir::OpBuilder::InsertPoint ip, mlir::Value ArraySize) {
assert(ip.isSet() && "Insertion point is not set");
return cast<mlir::cir::AllocaOp>(
buildAlloca(Name.str(), Ty, Loc, CharUnits(), insertIntoFnEntryBlock)
buildAlloca(Name.str(), Ty, Loc, CharUnits(), ip, ArraySize)
.getDefiningOp());
}

Expand Down
19 changes: 14 additions & 5 deletions clang/lib/CIR/CodeGen/CIRGenFunction.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -239,13 +239,16 @@ class CIRGenFunction : public CIRGenTypeCache {
// FIXME(cir): move this to CIRGenBuider.h
mlir::Value buildAlloca(llvm::StringRef name, clang::QualType ty,
mlir::Location loc, clang::CharUnits alignment,
bool insertIntoFnEntryBlock = false);
bool insertIntoFnEntryBlock = false,
mlir::Value arraySize = nullptr);
mlir::Value buildAlloca(llvm::StringRef name, mlir::Type ty,
mlir::Location loc, clang::CharUnits alignment,
bool insertIntoFnEntryBlock = false);
bool insertIntoFnEntryBlock = false,
mlir::Value arraySize = nullptr);
mlir::Value buildAlloca(llvm::StringRef name, mlir::Type ty,
mlir::Location loc, clang::CharUnits alignment,
mlir::OpBuilder::InsertPoint ip);
mlir::OpBuilder::InsertPoint ip,
mlir::Value arraySize = nullptr);

private:
void buildAndUpdateRetAlloca(clang::QualType ty, mlir::Location loc,
Expand Down Expand Up @@ -1877,14 +1880,20 @@ class CIRGenFunction : public CIRGenTypeCache {
CreateTempAllocaInFnEntryBlock(mlir::Type Ty, mlir::Location Loc,
const Twine &Name = "tmp",
mlir::Value ArraySize = nullptr);
mlir::cir::AllocaOp CreateTempAlloca(mlir::Type Ty, mlir::Location Loc,
const Twine &Name = "tmp",
mlir::OpBuilder::InsertPoint ip = {},
mlir::Value ArraySize = nullptr);
Address CreateTempAlloca(mlir::Type Ty, CharUnits align, mlir::Location Loc,
const Twine &Name = "tmp",
mlir::Value ArraySize = nullptr,
Address *Alloca = nullptr);
Address *Alloca = nullptr,
mlir::OpBuilder::InsertPoint ip = {});
Address CreateTempAllocaWithoutCast(mlir::Type Ty, CharUnits align,
mlir::Location Loc,
const Twine &Name = "tmp",
mlir::Value ArraySize = nullptr);
mlir::Value ArraySize = nullptr,
mlir::OpBuilder::InsertPoint ip = {});

/// Create a temporary memory object of the given type, with
/// appropriate alignmen and cast it to the default address space. Returns
Expand Down

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