clang  3.7.0
CGCall.h
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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"
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 
28 namespace llvm {
29  class AttributeSet;
30  class Function;
31  class Type;
32  class Value;
33 }
34 
35 namespace clang {
36  class ASTContext;
37  class Decl;
38  class FunctionDecl;
39  class ObjCMethodDecl;
40  class VarDecl;
41 
42 namespace CodeGen {
44 
45  struct CallArg {
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.
65 
66  /// The temporary alloca.
68 
69  /// A value to "use" after the writeback, or null.
71  };
72 
73  struct CallArgCleanup {
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>
104 
106  return writeback_const_range(Writebacks.begin(), Writebacks.end());
107  }
108 
110  llvm::Instruction *IsActiveIP) {
111  CallArgCleanup ArgCleanup;
112  ArgCleanup.Cleanup = Cleanup;
113  ArgCleanup.IsActiveIP = IsActiveIP;
114  CleanupsToDeactivate.push_back(ArgCleanup);
115  }
116 
118  return CleanupsToDeactivate;
119  }
120 
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.
158  llvm::PointerIntPair<llvm::Value *, 2, unsigned int> Value;
159 
160  // Return value slot flags
161  enum Flags {
162  IS_VOLATILE = 0x1,
163  IS_UNUSED = 0x2,
164  };
165 
166  public:
168  ReturnValueSlot(llvm::Value *Value, bool IsVolatile, bool IsUnused = false)
169  : Value(Value,
170  (IsVolatile ? IS_VOLATILE : 0) | (IsUnused ? IS_UNUSED : 0)) {}
171 
172  bool isNull() const { return !getValue(); }
173 
174  bool isVolatile() const { return Value.getInt() & IS_VOLATILE; }
175  llvm::Value *getValue() const { return Value.getPointer(); }
176  bool isUnused() const { return Value.getInt() & IS_UNUSED; }
177  };
178 
179 } // end namespace CodeGen
180 } // end namespace clang
181 
182 #endif
void freeArgumentMemory(CodeGenFunction &CGF) const
Definition: CGCall.cpp:2773
llvm::Value * getValue() const
Definition: CGCall.h:175
SmallVector< llvm::AttributeSet, 8 > AttributeListType
Definition: CGCall.h:43
EHScopeStack::stable_iterator Cleanup
Definition: CGCall.h:74
void addWriteback(LValue srcLV, llvm::Value *temporary, llvm::Value *toUse)
Definition: CGCall.h:91
void addArgCleanupDeactivation(EHScopeStack::stable_iterator Cleanup, llvm::Instruction *IsActiveIP)
Definition: CGCall.h:109
CallArg(RValue rv, QualType ty, bool needscopy)
Definition: CGCall.h:49
llvm::iterator_range< SmallVectorImpl< Writeback >::const_iterator > writeback_const_range
Definition: CGCall.h:103
void addFrom(const CallArgList &other)
Definition: CGCall.h:85
writeback_const_range writebacks() const
Definition: CGCall.h:105
ArrayRef< CallArgCleanup > getCleanupsToDeactivate() const
Definition: CGCall.h:117
llvm::Value * ToUse
A value to "use" after the writeback, or null.
Definition: CGCall.h:70
void add(RValue rvalue, QualType type, bool needscopy=false)
Definition: CGCall.h:81
bool hasWritebacks() const
Definition: CGCall.h:100
llvm::Value * Temporary
The temporary alloca.
Definition: CGCall.h:67
void allocateArgumentMemory(CodeGenFunction &CGF)
Definition: CGCall.cpp:2755
const internal::VariadicAllOfMatcher< Type > type
Matches Types in the clang AST.
Definition: ASTMatchers.h:1639
bool isUsingInAlloca() const
Returns if we're using an inalloca struct to pass arguments in memory.
Definition: CGCall.h:127
llvm::Instruction * getStackBase() const
Definition: CGCall.h:122
ReturnValueSlot(llvm::Value *Value, bool IsVolatile, bool IsUnused=false)
Definition: CGCall.h:168