IRGen-level lowering for the Swift calling convention.

llvm-svn: 265324

clang/include/clang/CodeGen/SwiftCallingConv.h

@@ -0,0 +1,168 @@
+//==-- SwiftCallingConv.h - Swift ABI lowering -----------------------------==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Defines constants and types related to Swift ABI lowering.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_CODEGEN_SWIFTCALLINGCONV_H
+#define LLVM_CLANG_CODEGEN_SWIFTCALLINGCONV_H
+
+#include "clang/AST/CanonicalType.h"
+#include "clang/AST/CharUnits.h"
+#include "clang/AST/Type.h"
+#include "llvm/ADT/FoldingSet.h"
+#include "llvm/Support/TrailingObjects.h"
+#include <cassert>
+
+namespace llvm {
+  class IntegerType;
+  class Type;
+  class StructType;
+  class VectorType;
+}
+
+namespace clang {
+class Decl;
+class FieldDecl;
+class ASTRecordLayout;
+
+namespace CodeGen {
+class ABIArgInfo;
+class CodeGenModule;
+class CGFunctionInfo;
+
+namespace swiftcall {
+
+class SwiftAggLowering {
+  CodeGenModule &CGM;
+
+  struct StorageEntry {
+    CharUnits Begin;
+    CharUnits End;
+    llvm::Type *Type;
+
+    CharUnits getWidth() const {
+      return End - Begin;
+    }
+  };
+  SmallVector<StorageEntry, 4> Entries;
+  bool Finished = false;
+
+public:
+  SwiftAggLowering(CodeGenModule &CGM) : CGM(CGM) {}
+
+  void addOpaqueData(CharUnits begin, CharUnits end) {
+    addEntry(nullptr, begin, end);
+  }
+
+  void addTypedData(QualType type, CharUnits begin);
+  void addTypedData(const RecordDecl *record, CharUnits begin);
+  void addTypedData(const RecordDecl *record, CharUnits begin,
+                    const ASTRecordLayout &layout);
+  void addTypedData(llvm::Type *type, CharUnits begin);
+  void addTypedData(llvm::Type *type, CharUnits begin, CharUnits end);
+
+  void finish();
+
+  /// Does this lowering require passing any data?
+  bool empty() const {
+    assert(Finished && "didn't finish lowering before calling empty()");
+    return Entries.empty();
+  }
+
+  /// According to the target Swift ABI, should a value with this lowering
+  /// be passed indirectly?
+  ///
+  /// Note that this decision is based purely on the data layout of the
+  /// value and does not consider whether the type is address-only,
+  /// must be passed indirectly to match a function abstraction pattern, or
+  /// anything else that is expected to be handled by high-level lowering.
+  ///
+  /// \param asReturnValue - if true, answer whether it should be passed
+  ///   indirectly as a return value; if false, answer whether it should be
+  ///   passed indirectly as an argument
+  bool shouldPassIndirectly(bool asReturnValue) const;
+
+  using EnumerationCallback =
+    llvm::function_ref<void(CharUnits offset, llvm::Type *type)>;
+
+  /// Enumerate the expanded components of this type.
+  ///
+  /// The component types will always be legal vector, floating-point,
+  /// integer, or pointer types.
+  void enumerateComponents(EnumerationCallback callback) const;
+
+  /// Return the types for a coerce-and-expand operation.
+  ///
+  /// The first type matches the memory layout of the data that's been
+  /// added to this structure, including explicit [N x i8] arrays for any
+  /// internal padding.
+  ///
+  /// The second type removes any internal padding members and, if only
+  /// one element remains, is simply that element type.
+  std::pair<llvm::StructType*, llvm::Type*> getCoerceAndExpandTypes() const;
+
+private:
+  void addBitFieldData(const FieldDecl *field, CharUnits begin,
+                       uint64_t bitOffset);
+  void addLegalTypedData(llvm::Type *type, CharUnits begin, CharUnits end);
+  void addEntry(llvm::Type *type, CharUnits begin, CharUnits end);
+  void splitVectorEntry(unsigned index);
+};
+
+/// Return the maximum voluntary integer size for the current target.
+CharUnits getMaximumVoluntaryIntegerSize(CodeGenModule &CGM);
+
+/// Return the Swift CC's notion of the natural alignment of a type.
+CharUnits getNaturalAlignment(CodeGenModule &CGM, llvm::Type *type);
+
+/// Is the given integer type "legal" for Swift's perspective on the
+/// current platform?
+bool isLegalIntegerType(CodeGenModule &CGM, llvm::IntegerType *type);
+
+/// Is the given vector type "legal" for Swift's perspective on the
+/// current platform?
+bool isLegalVectorType(CodeGenModule &CGM, CharUnits vectorSize,
+                       llvm::VectorType *vectorTy);
+bool isLegalVectorType(CodeGenModule &CGM, CharUnits vectorSize,
+                       llvm::Type *eltTy, unsigned numElts);
+
+/// Minimally split a legal vector type.
+std::pair<llvm::Type*, unsigned>
+splitLegalVectorType(CodeGenModule &CGM, CharUnits vectorSize,
+                     llvm::VectorType *vectorTy);
+
+/// Turn a vector type in a sequence of legal component vector types.
+///
+/// The caller may assume that the sum of the data sizes of the resulting
+/// types will equal the data size of the vector type.
+void legalizeVectorType(CodeGenModule &CGM, CharUnits vectorSize,
+                        llvm::VectorType *vectorTy,
+                        llvm::SmallVectorImpl<llvm::Type*> &types);
+
+/// Should a C++ record type be passed and returned indirectly?
+bool shouldPassCXXRecordIndirectly(CodeGenModule &CGM,
+                                   const CXXRecordDecl *record);
+
+/// Classify the rules for how to return a particular type.
+ABIArgInfo classifyReturnType(CodeGenModule &CGM, CanQualType type);
+
+/// Classify the rules for how to pass a particular type.
+ABIArgInfo classifyArgumentType(CodeGenModule &CGM, CanQualType type);
+
+/// Compute the ABI information of a swiftcall function.  This is a
+/// private interface for Clang.
+void computeABIInfo(CodeGenModule &CGM, CGFunctionInfo &FI);
+
+} // end namespace swiftcall
+} // end namespace CodeGen
+} // end namespace clang
+
+#endif

clang/lib/CodeGen/ABIInfo.h

@@ -18,20 +18,25 @@ namespace llvm {
   class Value;
   class LLVMContext;
   class DataLayout;
+  class Type;
 }
 
 namespace clang {
   class ASTContext;
   class TargetInfo;
 
-  namespace CodeGen {
-    class ABIArgInfo;
-    class Address;
-    class CGCXXABI;
-    class CGFunctionInfo;
-    class CodeGenFunction;
-    class CodeGenTypes;
-  }
+namespace CodeGen {
+  class ABIArgInfo;
+  class Address;
+  class CGCXXABI;
+  class CGFunctionInfo;
+  class CodeGenFunction;
+  class CodeGenTypes;
+  class SwiftABIInfo;
+
+namespace swiftcall {
+  class SwiftAggLowering;
+}
 
   // FIXME: All of this stuff should be part of the target interface
   // somehow. It is currently here because it is not clear how to factor
@@ -55,6 +60,8 @@ namespace clang {
 
     virtual ~ABIInfo();
 
+    virtual bool supportsSwift() const { return false; }
+
     CodeGen::CGCXXABI &getCXXABI() const;
     ASTContext &getContext() const;
     llvm::LLVMContext &getVMContext() const;
@@ -112,7 +119,35 @@ namespace clang {
 
     CodeGen::ABIArgInfo
     getNaturalAlignIndirectInReg(QualType Ty, bool Realign = false) const;
+
+
   };
+
+  /// A refining implementation of ABIInfo for targets that support swiftcall.
+  ///
+  /// If we find ourselves wanting multiple such refinements, they'll probably
+  /// be independent refinements, and we should probably find another way
+  /// to do it than simple inheritance.
+  class SwiftABIInfo : public ABIInfo {
+  public:
+    SwiftABIInfo(CodeGen::CodeGenTypes &cgt) : ABIInfo(cgt) {}
+
+    bool supportsSwift() const final override { return true; }
+
+    virtual bool shouldPassIndirectlyForSwift(CharUnits totalSize,
+                                              ArrayRef<llvm::Type*> types,
+                                              bool asReturnValue) const = 0;
+
+    virtual bool isLegalVectorTypeForSwift(CharUnits totalSize,
+                                           llvm::Type *eltTy,
+                                           unsigned elts) const;
+
+    static bool classof(const ABIInfo *info) {
+      return info->supportsSwift();
+    }
+  };
+
+}  // end namespace CodeGen
 }  // end namespace clang
 
 #endif