[clang] [llvm] [WIP] ABI Lowering Library (PR #140112)

[Nikita Popov via llvm-commits]

================
@@ -0,0 +1,282 @@
+//===- ABI/Types.h ----------------------------------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file defines the Types and related helper methods concerned to the
+/// LLVMABI library which mirrors ABI related type information from
+/// the LLVM frontend.
+///
+//===----------------------------------------------------------------------===//
+#ifndef LLVM_ABI_TYPES_H
+#define LLVM_ABI_TYPES_H
+
+#include "llvm/ADT/APFloat.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/IR/CallingConv.h"
+#include "llvm/Support/Alignment.h"
+#include "llvm/Support/Allocator.h"
+#include "llvm/Support/TypeSize.h"
+#include <cstdint>
+
+namespace llvm {
+namespace abi {
+
+enum class TypeKind {
+  Void,
+  Integer,
+  Float,
+  Pointer,
+  Array,
+  Vector,
+  Struct,
+  Union,
+};
+
+class Type {
+protected:
+  TypeKind Kind;
+  TypeSize SizeInBits;
+  Align Alignment;
+  bool IsExplicitlyAligned;
+
+  Type(TypeKind K, TypeSize Size, Align Align, bool ExplicitAlign = false)
+      : Kind(K), SizeInBits(Size), Alignment(Align),
+        IsExplicitlyAligned(ExplicitAlign) {}
+
+public:
+  TypeKind getKind() const { return Kind; }
+  TypeSize getSizeInBits() const { return SizeInBits; }
+  Align getAlignment() const { return Alignment; }
+  bool hasExplicitAlignment() const { return IsExplicitlyAligned; }
+
+  void setExplicitAlignment(Align Align) {
+    Alignment = Align;
+    IsExplicitlyAligned = true;
+  }
+
+  bool isVoid() const { return Kind == TypeKind::Void; }
+  bool isInteger() const { return Kind == TypeKind::Integer; }
+  bool isFloat() const { return Kind == TypeKind::Float; }
+  bool isPointer() const { return Kind == TypeKind::Pointer; }
+  bool isArray() const { return Kind == TypeKind::Array; }
+  bool isVector() const { return Kind == TypeKind::Vector; }
+  bool isStruct() const { return Kind == TypeKind::Struct; }
+  bool isUnion() const { return Kind == TypeKind::Union; }
+};
+
+class VoidType : public Type {
+public:
+  VoidType() : Type(TypeKind::Void, TypeSize::getFixed(0), Align(1)) {}
+
+  static bool classof(const Type *T) { return T->getKind() == TypeKind::Void; }
+};
+
+class IntegerType : public Type {
+private:
+  bool IsSigned;
+
+public:
+  IntegerType(uint64_t BitWidth, Align Align, bool Signed)
+      : Type(TypeKind::Integer, TypeSize::getFixed(BitWidth), Align),
+        IsSigned(Signed) {}
+
+  bool isSigned() const { return IsSigned; }
+
+  static bool classof(const Type *T) {
+    return T->getKind() == TypeKind::Integer;
+  }
+};
+
+class FloatType : public Type {
+private:
+  const fltSemantics *Semantics;
+
+public:
+  FloatType(const fltSemantics &FloatSemantics, Align Align)
+      : Type(TypeKind::Float,
+             TypeSize::getFixed(APFloat::getSizeInBits(FloatSemantics)), Align),
+        Semantics(&FloatSemantics) {}
+
+  static bool classof(const Type *T) { return T->getKind() == TypeKind::Float; }
+};
+
+class PointerType : public Type {
+public:
+  PointerType(uint64_t Size, Align Align)
+      : Type(TypeKind::Pointer, TypeSize::getFixed(Size), Align) {}
+
+  static bool classof(const Type *T) {
+    return T->getKind() == TypeKind::Pointer;
+  }
+};
+
+class ArrayType : public Type {
+private:
+  const Type *ElementType;
+  uint64_t NumElements;
+
+public:
+  ArrayType(const Type *ElemType, uint64_t NumElems)
+      : Type(TypeKind::Array, ElemType->getSizeInBits() * NumElems,
+             ElemType->getAlignment()),
+        ElementType(ElemType), NumElements(NumElems) {}
+
+  const Type *getElementType() const { return ElementType; }
+  uint64_t getNumElements() const { return NumElements; }
+
+  static bool classof(const Type *T) { return T->getKind() == TypeKind::Array; }
+};
+
+class VectorType : public Type {
+private:
+  const Type *ElementType;
+  ElementCount NumElements;
+
+public:
+  VectorType(const Type *ElemType, ElementCount NumElems, Align Align)
+      : Type(
+            TypeKind::Vector,
+            NumElems.isScalable()
+                ? TypeSize(ElemType->getSizeInBits().getFixedValue() *
+                               NumElems.getKnownMinValue(),
+                           true)
----------------
nikic wrote:

```suggestion
                           NumElems.isScalable())
```
And then you don't need the ternary?

https://github.com/llvm/llvm-project/pull/140112