1//===----- CGCall.h - Encapsulate calling convention details ----*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// These classes wrap the information about a call or function
11// definition used to handle ABI compliancy.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef CLANG_CODEGEN_CGCALL_H
16#define CLANG_CODEGEN_CGCALL_H
17
18#include "CGValue.h"
19#include "EHScopeStack.h"
20#include "clang/AST/CanonicalType.h"
21#include "clang/AST/Type.h"
22#include "llvm/ADT/FoldingSet.h"
23#include "llvm/IR/Value.h"
24
25// FIXME: Restructure so we don't have to expose so much stuff.
26#include "ABIInfo.h"
27
28namespace llvm {
29  class AttributeSet;
30  class Function;
31  class Type;
32  class Value;
33}
34
35namespace clang {
36  class ASTContext;
37  class Decl;
38  class FunctionDecl;
39  class ObjCMethodDecl;
40  class VarDecl;
41
42namespace CodeGen {
43  typedef SmallVector<llvm::AttributeSet, 8> AttributeListType;
44
45  struct CallArg {
46    RValue RV;
47    QualType Ty;
48    bool NeedsCopy;
49    CallArg(RValue rv, QualType ty, bool needscopy)
50    : RV(rv), Ty(ty), NeedsCopy(needscopy)
51    { }
52  };
53
54  /// CallArgList - Type for representing both the value and type of
55  /// arguments in a call.
56  class CallArgList :
57    public SmallVector<CallArg, 16> {
58  public:
59    CallArgList() : StackBase(nullptr), StackBaseMem(nullptr) {}
60
61    struct Writeback {
62      /// The original argument.  Note that the argument l-value
63      /// is potentially null.
64      LValue Source;
65
66      /// The temporary alloca.
67      llvm::Value *Temporary;
68
69      /// A value to "use" after the writeback, or null.
70      llvm::Value *ToUse;
71    };
72
73    struct CallArgCleanup {
74      EHScopeStack::stable_iterator Cleanup;
75
76      /// The "is active" insertion point.  This instruction is temporary and
77      /// will be removed after insertion.
78      llvm::Instruction *IsActiveIP;
79    };
80
81    void add(RValue rvalue, QualType type, bool needscopy = false) {
82      push_back(CallArg(rvalue, type, needscopy));
83    }
84
85    void addFrom(const CallArgList &other) {
86      insert(end(), other.begin(), other.end());
87      Writebacks.insert(Writebacks.end(),
88                        other.Writebacks.begin(), other.Writebacks.end());
89    }
90
91    void addWriteback(LValue srcLV, llvm::Value *temporary,
92                      llvm::Value *toUse) {
93      Writeback writeback;
94      writeback.Source = srcLV;
95      writeback.Temporary = temporary;
96      writeback.ToUse = toUse;
97      Writebacks.push_back(writeback);
98    }
99
100    bool hasWritebacks() const { return !Writebacks.empty(); }
101
102    typedef llvm::iterator_range<SmallVectorImpl<Writeback>::const_iterator>
103      writeback_const_range;
104
105    writeback_const_range writebacks() const {
106      return writeback_const_range(Writebacks.begin(), Writebacks.end());
107    }
108
109    void addArgCleanupDeactivation(EHScopeStack::stable_iterator Cleanup,
110                                   llvm::Instruction *IsActiveIP) {
111      CallArgCleanup ArgCleanup;
112      ArgCleanup.Cleanup = Cleanup;
113      ArgCleanup.IsActiveIP = IsActiveIP;
114      CleanupsToDeactivate.push_back(ArgCleanup);
115    }
116
117    ArrayRef<CallArgCleanup> getCleanupsToDeactivate() const {
118      return CleanupsToDeactivate;
119    }
120
121    void allocateArgumentMemory(CodeGenFunction &CGF);
122    llvm::Instruction *getStackBase() const { return StackBase; }
123    void freeArgumentMemory(CodeGenFunction &CGF) const;
124
125    /// \brief Returns if we're using an inalloca struct to pass arguments in
126    /// memory.
127    bool isUsingInAlloca() const { return StackBase; }
128
129  private:
130    SmallVector<Writeback, 1> Writebacks;
131
132    /// Deactivate these cleanups immediately before making the call.  This
133    /// is used to cleanup objects that are owned by the callee once the call
134    /// occurs.
135    SmallVector<CallArgCleanup, 1> CleanupsToDeactivate;
136
137    /// The stacksave call.  It dominates all of the argument evaluation.
138    llvm::CallInst *StackBase;
139
140    /// The alloca holding the stackbase.  We need it to maintain SSA form.
141    llvm::AllocaInst *StackBaseMem;
142
143    /// The iterator pointing to the stack restore cleanup.  We manually run and
144    /// deactivate this cleanup after the call in the unexceptional case because
145    /// it doesn't run in the normal order.
146    EHScopeStack::stable_iterator StackCleanup;
147  };
148
149  /// FunctionArgList - Type for representing both the decl and type
150  /// of parameters to a function. The decl must be either a
151  /// ParmVarDecl or ImplicitParamDecl.
152  class FunctionArgList : public SmallVector<const VarDecl*, 16> {
153  };
154
155  /// ReturnValueSlot - Contains the address where the return value of a
156  /// function can be stored, and whether the address is volatile or not.
157  class ReturnValueSlot {
158    llvm::PointerIntPair<llvm::Value *, 1, bool> Value;
159
160  public:
161    ReturnValueSlot() {}
162    ReturnValueSlot(llvm::Value *Value, bool IsVolatile)
163      : Value(Value, IsVolatile) {}
164
165    bool isNull() const { return !getValue(); }
166
167    bool isVolatile() const { return Value.getInt(); }
168    llvm::Value *getValue() const { return Value.getPointer(); }
169  };
170
171}  // end namespace CodeGen
172}  // end namespace clang
173
174#endif
175