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 LLVM_CLANG_LIB_CODEGEN_CGCALL_H
16#define LLVM_CLANG_LIB_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) {}
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      Address 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, Address temporary,
92                      llvm::Value *toUse) {
93      Writeback writeback = { srcLV, temporary, toUse };
94      Writebacks.push_back(writeback);
95    }
96
97    bool hasWritebacks() const { return !Writebacks.empty(); }
98
99    typedef llvm::iterator_range<SmallVectorImpl<Writeback>::const_iterator>
100      writeback_const_range;
101
102    writeback_const_range writebacks() const {
103      return writeback_const_range(Writebacks.begin(), Writebacks.end());
104    }
105
106    void addArgCleanupDeactivation(EHScopeStack::stable_iterator Cleanup,
107                                   llvm::Instruction *IsActiveIP) {
108      CallArgCleanup ArgCleanup;
109      ArgCleanup.Cleanup = Cleanup;
110      ArgCleanup.IsActiveIP = IsActiveIP;
111      CleanupsToDeactivate.push_back(ArgCleanup);
112    }
113
114    ArrayRef<CallArgCleanup> getCleanupsToDeactivate() const {
115      return CleanupsToDeactivate;
116    }
117
118    void allocateArgumentMemory(CodeGenFunction &CGF);
119    llvm::Instruction *getStackBase() const { return StackBase; }
120    void freeArgumentMemory(CodeGenFunction &CGF) const;
121
122    /// \brief Returns if we're using an inalloca struct to pass arguments in
123    /// memory.
124    bool isUsingInAlloca() const { return StackBase; }
125
126  private:
127    SmallVector<Writeback, 1> Writebacks;
128
129    /// Deactivate these cleanups immediately before making the call.  This
130    /// is used to cleanup objects that are owned by the callee once the call
131    /// occurs.
132    SmallVector<CallArgCleanup, 1> CleanupsToDeactivate;
133
134    /// The stacksave call.  It dominates all of the argument evaluation.
135    llvm::CallInst *StackBase;
136
137    /// The iterator pointing to the stack restore cleanup.  We manually run and
138    /// deactivate this cleanup after the call in the unexceptional case because
139    /// it doesn't run in the normal order.
140    EHScopeStack::stable_iterator StackCleanup;
141  };
142
143  /// FunctionArgList - Type for representing both the decl and type
144  /// of parameters to a function. The decl must be either a
145  /// ParmVarDecl or ImplicitParamDecl.
146  class FunctionArgList : public SmallVector<const VarDecl*, 16> {
147  };
148
149  /// ReturnValueSlot - Contains the address where the return value of a
150  /// function can be stored, and whether the address is volatile or not.
151  class ReturnValueSlot {
152    llvm::PointerIntPair<llvm::Value *, 2, unsigned int> Value;
153    CharUnits Alignment;
154
155    // Return value slot flags
156    enum Flags {
157      IS_VOLATILE = 0x1,
158      IS_UNUSED = 0x2,
159    };
160
161  public:
162    ReturnValueSlot() {}
163    ReturnValueSlot(Address Addr, bool IsVolatile, bool IsUnused = false)
164      : Value(Addr.isValid() ? Addr.getPointer() : nullptr,
165              (IsVolatile ? IS_VOLATILE : 0) | (IsUnused ? IS_UNUSED : 0)),
166        Alignment(Addr.isValid() ? Addr.getAlignment() : CharUnits::Zero()) {}
167
168    bool isNull() const { return !getValue().isValid(); }
169
170    bool isVolatile() const { return Value.getInt() & IS_VOLATILE; }
171    Address getValue() const { return Address(Value.getPointer(), Alignment); }
172    bool isUnused() const { return Value.getInt() & IS_UNUSED; }
173  };
174
175}  // end namespace CodeGen
176}  // end namespace clang
177
178#endif
179