llvm-project/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp
2025-07-09 18:28:00 +02:00

239 lines
9.0 KiB
C++

//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This contains code to emit Builtin calls as CIR or a function call to be
// later resolved.
//
//===----------------------------------------------------------------------===//
#include "CIRGenCall.h"
#include "CIRGenConstantEmitter.h"
#include "CIRGenFunction.h"
#include "CIRGenModule.h"
#include "CIRGenValue.h"
#include "mlir/IR/BuiltinAttributes.h"
#include "mlir/IR/Value.h"
#include "mlir/Support/LLVM.h"
#include "clang/AST/Expr.h"
#include "clang/AST/GlobalDecl.h"
#include "clang/CIR/MissingFeatures.h"
#include "llvm/Support/ErrorHandling.h"
using namespace clang;
using namespace clang::CIRGen;
using namespace llvm;
static RValue emitLibraryCall(CIRGenFunction &cgf, const FunctionDecl *fd,
const CallExpr *e, mlir::Operation *calleeValue) {
CIRGenCallee callee = CIRGenCallee::forDirect(calleeValue, GlobalDecl(fd));
return cgf.emitCall(e->getCallee()->getType(), callee, e, ReturnValueSlot());
}
template <typename Op>
static RValue emitBuiltinBitOp(CIRGenFunction &cgf, const CallExpr *e,
bool poisonZero = false) {
assert(!cir::MissingFeatures::builtinCheckKind());
mlir::Value arg = cgf.emitScalarExpr(e->getArg(0));
CIRGenBuilderTy &builder = cgf.getBuilder();
Op op;
if constexpr (std::is_same_v<Op, cir::BitClzOp> ||
std::is_same_v<Op, cir::BitCtzOp>)
op = builder.create<Op>(cgf.getLoc(e->getSourceRange()), arg, poisonZero);
else
op = builder.create<Op>(cgf.getLoc(e->getSourceRange()), arg);
mlir::Value result = op.getResult();
mlir::Type exprTy = cgf.convertType(e->getType());
if (exprTy != result.getType())
result = builder.createIntCast(result, exprTy);
return RValue::get(result);
}
RValue CIRGenFunction::emitBuiltinExpr(const GlobalDecl &gd, unsigned builtinID,
const CallExpr *e,
ReturnValueSlot returnValue) {
// See if we can constant fold this builtin. If so, don't emit it at all.
// TODO: Extend this handling to all builtin calls that we can constant-fold.
Expr::EvalResult result;
if (e->isPRValue() && e->EvaluateAsRValue(result, cgm.getASTContext()) &&
!result.hasSideEffects()) {
if (result.Val.isInt()) {
return RValue::get(builder.getConstInt(getLoc(e->getSourceRange()),
result.Val.getInt()));
}
if (result.Val.isFloat()) {
// Note: we are using result type of CallExpr to determine the type of
// the constant. Classic codegen uses the result value to determine the
// type. We feel it should be Ok to use expression type because it is
// hard to imagine a builtin function evaluates to a value that
// over/underflows its own defined type.
mlir::Type type = convertType(e->getType());
return RValue::get(builder.getConstFP(getLoc(e->getExprLoc()), type,
result.Val.getFloat()));
}
}
const FunctionDecl *fd = gd.getDecl()->getAsFunction();
assert(!cir::MissingFeatures::builtinCallF128());
// If the builtin has been declared explicitly with an assembler label,
// disable the specialized emitting below. Ideally we should communicate the
// rename in IR, or at least avoid generating the intrinsic calls that are
// likely to get lowered to the renamed library functions.
unsigned builtinIDIfNoAsmLabel = fd->hasAttr<AsmLabelAttr>() ? 0 : builtinID;
assert(!cir::MissingFeatures::builtinCallMathErrno());
assert(!cir::MissingFeatures::builtinCall());
mlir::Location loc = getLoc(e->getExprLoc());
switch (builtinIDIfNoAsmLabel) {
default:
break;
case Builtin::BI__assume:
case Builtin::BI__builtin_assume: {
if (e->getArg(0)->HasSideEffects(getContext()))
return RValue::get(nullptr);
mlir::Value argValue = emitCheckedArgForAssume(e->getArg(0));
builder.create<cir::AssumeOp>(loc, argValue);
return RValue::get(nullptr);
}
case Builtin::BI__builtin_complex: {
mlir::Value real = emitScalarExpr(e->getArg(0));
mlir::Value imag = emitScalarExpr(e->getArg(1));
mlir::Value complex = builder.createComplexCreate(loc, real, imag);
return RValue::get(complex);
}
case Builtin::BI__builtin_creal:
case Builtin::BI__builtin_crealf:
case Builtin::BI__builtin_creall:
case Builtin::BIcreal:
case Builtin::BIcrealf:
case Builtin::BIcreall: {
mlir::Value complex = emitComplexExpr(e->getArg(0));
mlir::Value real = builder.createComplexReal(loc, complex);
return RValue::get(real);
}
case Builtin::BI__builtin_clrsb:
case Builtin::BI__builtin_clrsbl:
case Builtin::BI__builtin_clrsbll:
return emitBuiltinBitOp<cir::BitClrsbOp>(*this, e);
case Builtin::BI__builtin_ctzs:
case Builtin::BI__builtin_ctz:
case Builtin::BI__builtin_ctzl:
case Builtin::BI__builtin_ctzll:
case Builtin::BI__builtin_ctzg:
assert(!cir::MissingFeatures::builtinCheckKind());
return emitBuiltinBitOp<cir::BitCtzOp>(*this, e, /*poisonZero=*/true);
case Builtin::BI__builtin_clzs:
case Builtin::BI__builtin_clz:
case Builtin::BI__builtin_clzl:
case Builtin::BI__builtin_clzll:
case Builtin::BI__builtin_clzg:
assert(!cir::MissingFeatures::builtinCheckKind());
return emitBuiltinBitOp<cir::BitClzOp>(*this, e, /*poisonZero=*/true);
case Builtin::BI__builtin_parity:
case Builtin::BI__builtin_parityl:
case Builtin::BI__builtin_parityll:
return emitBuiltinBitOp<cir::BitParityOp>(*this, e);
case Builtin::BI__lzcnt16:
case Builtin::BI__lzcnt:
case Builtin::BI__lzcnt64:
assert(!cir::MissingFeatures::builtinCheckKind());
return emitBuiltinBitOp<cir::BitClzOp>(*this, e, /*poisonZero=*/false);
case Builtin::BI__popcnt16:
case Builtin::BI__popcnt:
case Builtin::BI__popcnt64:
case Builtin::BI__builtin_popcount:
case Builtin::BI__builtin_popcountl:
case Builtin::BI__builtin_popcountll:
case Builtin::BI__builtin_popcountg:
return emitBuiltinBitOp<cir::BitPopcountOp>(*this, e);
case Builtin::BI__builtin_expect:
case Builtin::BI__builtin_expect_with_probability: {
mlir::Value argValue = emitScalarExpr(e->getArg(0));
mlir::Value expectedValue = emitScalarExpr(e->getArg(1));
mlir::FloatAttr probAttr;
if (builtinIDIfNoAsmLabel == Builtin::BI__builtin_expect_with_probability) {
llvm::APFloat probability(0.0);
const Expr *probArg = e->getArg(2);
[[maybe_unused]] bool evalSucceeded =
probArg->EvaluateAsFloat(probability, cgm.getASTContext());
assert(evalSucceeded &&
"probability should be able to evaluate as float");
bool loseInfo = false; // ignored
probability.convert(llvm::APFloat::IEEEdouble(),
llvm::RoundingMode::Dynamic, &loseInfo);
probAttr = mlir::FloatAttr::get(mlir::Float64Type::get(&getMLIRContext()),
probability);
}
auto result = builder.create<cir::ExpectOp>(getLoc(e->getSourceRange()),
argValue.getType(), argValue,
expectedValue, probAttr);
return RValue::get(result);
}
}
// If this is an alias for a lib function (e.g. __builtin_sin), emit
// the call using the normal call path, but using the unmangled
// version of the function name.
if (getContext().BuiltinInfo.isLibFunction(builtinID))
return emitLibraryCall(*this, fd, e,
cgm.getBuiltinLibFunction(fd, builtinID));
cgm.errorNYI(e->getSourceRange(), "unimplemented builtin call");
return getUndefRValue(e->getType());
}
/// Given a builtin id for a function like "__builtin_fabsf", return a Function*
/// for "fabsf".
cir::FuncOp CIRGenModule::getBuiltinLibFunction(const FunctionDecl *fd,
unsigned builtinID) {
assert(astContext.BuiltinInfo.isLibFunction(builtinID));
// Get the name, skip over the __builtin_ prefix (if necessary). We may have
// to build this up so provide a small stack buffer to handle the vast
// majority of names.
llvm::SmallString<64> name;
assert(!cir::MissingFeatures::asmLabelAttr());
name = astContext.BuiltinInfo.getName(builtinID).substr(10);
GlobalDecl d(fd);
mlir::Type type = convertType(fd->getType());
return getOrCreateCIRFunction(name, type, d, /*forVTable=*/false);
}
mlir::Value CIRGenFunction::emitCheckedArgForAssume(const Expr *e) {
mlir::Value argValue = evaluateExprAsBool(e);
if (!sanOpts.has(SanitizerKind::Builtin))
return argValue;
assert(!cir::MissingFeatures::sanitizers());
cgm.errorNYI(e->getSourceRange(),
"emitCheckedArgForAssume: sanitizers are NYI");
return {};
}