//===- Target.h - target specific details -----------------------*- 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
//
//===----------------------------------------------------------------------===//
//
// Coding style: https://mlir.llvm.org/getting_started/DeveloperGuide/
//
//===----------------------------------------------------------------------===//
#ifndef FORTRAN_OPTMIZER_CODEGEN_TARGET_H
#define FORTRAN_OPTMIZER_CODEGEN_TARGET_H
#include "flang/Optimizer/Dialect/FIRType.h"
#include "flang/Optimizer/Dialect/Support/KindMapping.h"
#include "mlir/Dialect/LLVMIR/LLVMAttrs.h"
#include "mlir/IR/BuiltinTypes.h"
#include "llvm/TargetParser/Triple.h"
#include <memory>
#include <tuple>
#include <vector>
namespace mlir {
class DataLayout;
}
namespace fir {
namespace details {
/// Extra information about how to marshal an argument or return value that
/// modifies a signature per a particular ABI's calling convention.
/// Note: llvm::Attribute is not used directly, because its use depends on an
/// LLVMContext.
class Attributes {
public:
enum class IntegerExtension { None, Zero, Sign };
Attributes(unsigned short alignment = 0, bool byval = false,
bool sret = false, bool append = false,
IntegerExtension intExt = IntegerExtension::None)
: alignment{alignment}, byval{byval}, sret{sret}, append{append},
intExt{intExt} {}
unsigned getAlignment() const { return alignment; }
bool hasAlignment() const { return alignment != 0; }
bool isByVal() const { return byval; }
bool isSRet() const { return sret; }
bool isAppend() const { return append; }
bool isZeroExt() const { return intExt == IntegerExtension::Zero; }
bool isSignExt() const { return intExt == IntegerExtension::Sign; }
llvm::StringRef getIntExtensionAttrName() const;
private:
unsigned short alignment{};
bool byval : 1;
bool sret : 1;
bool append : 1;
IntegerExtension intExt;
};
} // namespace details
/// Some details of how to represent certain features depend on the target and
/// ABI that is being used. These specifics are captured here and guide the
/// lowering of FIR to LLVM-IR dialect.
class CodeGenSpecifics {
public:
using Attributes = details::Attributes;
using TypeAndAttr = std::tuple<mlir::Type, Attributes>;
using Marshalling = std::vector<TypeAndAttr>;
static std::unique_ptr<CodeGenSpecifics>
get(mlir::MLIRContext *ctx, llvm::Triple &&trp, KindMapping &&kindMap,
llvm::StringRef targetCPU, mlir::LLVM::TargetFeaturesAttr targetFeatures,
const mlir::DataLayout &dl);
static std::unique_ptr<CodeGenSpecifics>
get(mlir::MLIRContext *ctx, llvm::Triple &&trp, KindMapping &&kindMap,
llvm::StringRef targetCPU, mlir::LLVM::TargetFeaturesAttr targetFeatures,
const mlir::DataLayout &dl, llvm::StringRef tuneCPU);
static TypeAndAttr getTypeAndAttr(mlir::Type t) { return TypeAndAttr{t, {}}; }
CodeGenSpecifics(mlir::MLIRContext *ctx, llvm::Triple &&trp,
KindMapping &&kindMap, llvm::StringRef targetCPU,
mlir::LLVM::TargetFeaturesAttr targetFeatures,
const mlir::DataLayout &dl)
: context{*ctx}, triple{std::move(trp)}, kindMap{std::move(kindMap)},
targetCPU{targetCPU}, targetFeatures{targetFeatures}, dataLayout{&dl},
tuneCPU{""} {}
CodeGenSpecifics(mlir::MLIRContext *ctx, llvm::Triple &&trp,
KindMapping &&kindMap, llvm::StringRef targetCPU,
mlir::LLVM::TargetFeaturesAttr targetFeatures,
const mlir::DataLayout &dl, llvm::StringRef tuneCPU)
: context{*ctx}, triple{std::move(trp)}, kindMap{std::move(kindMap)},
targetCPU{targetCPU}, targetFeatures{targetFeatures}, dataLayout{&dl},
tuneCPU{tuneCPU} {}
CodeGenSpecifics() = delete;
virtual ~CodeGenSpecifics() {}
/// Type presentation of a `complex<ele>` type value in memory.
virtual mlir::Type complexMemoryType(mlir::Type eleTy) const = 0;
/// Type representation of a `complex<eleTy>` type argument when passed by
/// value. An argument value may need to be passed as a (safe) reference
/// argument.
virtual Marshalling complexArgumentType(mlir::Location loc,
mlir::Type eleTy) const = 0;
/// Type representation of a `complex<eleTy>` type return value. Such a return
/// value may need to be converted to a hidden reference argument.
virtual Marshalling complexReturnType(mlir::Location loc,
mlir::Type eleTy) const = 0;
/// Type presentation of a `boxchar<n>` type value in memory.
virtual mlir::Type boxcharMemoryType(mlir::Type eleTy) const = 0;
/// Type representation of a `fir.type<T>` type argument when passed by
/// value. It may have to be split into several arguments, or be passed
/// as a byval reference argument (on the stack).
virtual Marshalling
structArgumentType(mlir::Location loc, fir::RecordType recTy,
const Marshalling &previousArguments) const = 0;
/// Type representation of a `boxchar<n>` type argument when passed by value.
/// An argument value may need to be passed as a (safe) reference argument.
///
/// A function that returns a `boxchar<n>` type value must already have
/// converted that return value to a parameter decorated with the 'sret'
/// Attribute (https://llvm.org/docs/LangRef.html#parameter-attributes).
/// This requirement is in keeping with Fortran semantics, which require the
/// caller to allocate the space for the return CHARACTER value and pass
/// a pointer and the length of that space (a boxchar) to the called function.
virtual Marshalling boxcharArgumentType(mlir::Type eleTy,
bool sret = false) const = 0;
// Compute ABI rules for an integer argument of the given mlir::IntegerType
// \p argTy. Note that this methods is supposed to be called for
// arguments passed by value not via reference, e.g. the 'i1' argument here:
// declare i1 @_FortranAioOutputLogical(ptr, i1)
//
// \p loc is the location of the operation using/specifying the argument.
//
// Currently, the only supported marshalling is whether the argument
// should be zero or sign extended.
//
// The zero/sign extension is especially important to comply with the ABI
// used by C/C++ compiler that builds Fortran runtime. As in the above
// example the callee will expect the caller to zero extend the second
// argument up to the size of the C/C++'s 'int' type.
// The corresponding handling in clang is done in
// DefaultABIInfo::classifyArgumentType(), and the logic may brielfy
// be explained as some sort of extension is required if the integer
// type is shorter than the size of 'int' for the target.
// The related code is located in ASTContext::isPromotableIntegerType()
// and ABIInfo::isPromotableIntegerTypeForABI().
// In particular, the latter returns 'true' for 'bool', several kinds
// of 'char', 'short', 'wchar' and enumerated types.
// The type of the extensions (zero or sign) depends on the signedness
// of the original language type.
//
// It is not clear how to handle signless integer types.
// From the point of Fortran-C interface all supported integer types
// seem to be signed except for CFI_type_Bool/bool that is supported
// via signless 'i1', but that is treated as unsigned type by clang
// (e.g. 'bool' arguments are using 'zeroext' ABI).
virtual Marshalling integerArgumentType(mlir::Location loc,
mlir::IntegerType argTy) const = 0;
// By default, integer argument and return values use the same
// zero/sign extension rules.
virtual Marshalling integerReturnType(mlir::Location loc,
mlir::IntegerType argTy) const = 0;
// Returns width in bits of C/C++ 'int' type size.
virtual unsigned char getCIntTypeWidth() const = 0;
llvm::StringRef getTargetCPU() const { return targetCPU; }
llvm::StringRef getTuneCPU() const { return tuneCPU; }
mlir::LLVM::TargetFeaturesAttr getTargetFeatures() const {
return targetFeatures;
}
const mlir::DataLayout &getDataLayout() const {
assert(dataLayout && "dataLayout must be set");
return *dataLayout;
}
protected:
mlir::MLIRContext &context;
llvm::Triple triple;
KindMapping kindMap;
llvm::StringRef targetCPU;
mlir::LLVM::TargetFeaturesAttr targetFeatures;
const mlir::DataLayout *dataLayout = nullptr;
llvm::StringRef tuneCPU;
};
} // namespace fir
#endif // FORTRAN_OPTMIZER_CODEGEN_TARGET_H
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