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CGCall.h
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1 //===----- CGCall.h - Encapsulate calling convention details ----*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // These classes wrap the information about a call or function
10 // definition used to handle ABI compliancy.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CLANG_LIB_CODEGEN_CGCALL_H
15 #define LLVM_CLANG_LIB_CODEGEN_CGCALL_H
16 
17 #include "CGValue.h"
18 #include "EHScopeStack.h"
20 #include "clang/AST/GlobalDecl.h"
21 #include "clang/AST/Type.h"
22 #include "llvm/IR/Value.h"
23 
24 // FIXME: Restructure so we don't have to expose so much stuff.
25 #include "ABIInfo.h"
26 
27 namespace llvm {
28 class AttributeList;
29 class Function;
30 class Type;
31 class Value;
32 }
33 
34 namespace clang {
35  class ASTContext;
36  class Decl;
37  class FunctionDecl;
38  class ObjCMethodDecl;
39  class VarDecl;
40 
41 namespace CodeGen {
42 
43 /// Abstract information about a function or function prototype.
44 class CGCalleeInfo {
45  /// The function prototype of the callee.
46  const FunctionProtoType *CalleeProtoTy;
47  /// The function declaration of the callee.
48  GlobalDecl CalleeDecl;
49 
50 public:
51  explicit CGCalleeInfo() : CalleeProtoTy(nullptr), CalleeDecl() {}
52  CGCalleeInfo(const FunctionProtoType *calleeProtoTy, GlobalDecl calleeDecl)
53  : CalleeProtoTy(calleeProtoTy), CalleeDecl(calleeDecl) {}
54  CGCalleeInfo(const FunctionProtoType *calleeProtoTy)
55  : CalleeProtoTy(calleeProtoTy), CalleeDecl() {}
57  : CalleeProtoTy(nullptr), CalleeDecl(calleeDecl) {}
58 
60  return CalleeProtoTy;
61  }
62  const GlobalDecl getCalleeDecl() const { return CalleeDecl; }
63  };
64 
65  /// All available information about a concrete callee.
66  class CGCallee {
67  enum class SpecialKind : uintptr_t {
68  Invalid,
69  Builtin,
70  PseudoDestructor,
71  Virtual,
72 
73  Last = Virtual
74  };
75 
76  struct BuiltinInfoStorage {
77  const FunctionDecl *Decl;
78  unsigned ID;
79  };
80  struct PseudoDestructorInfoStorage {
82  };
83  struct VirtualInfoStorage {
84  const CallExpr *CE;
85  GlobalDecl MD;
86  Address Addr;
87  llvm::FunctionType *FTy;
88  };
89 
90  SpecialKind KindOrFunctionPointer;
91  union {
93  BuiltinInfoStorage BuiltinInfo;
94  PseudoDestructorInfoStorage PseudoDestructorInfo;
95  VirtualInfoStorage VirtualInfo;
96  };
97 
98  explicit CGCallee(SpecialKind kind) : KindOrFunctionPointer(kind) {}
99 
100  CGCallee(const FunctionDecl *builtinDecl, unsigned builtinID)
101  : KindOrFunctionPointer(SpecialKind::Builtin) {
102  BuiltinInfo.Decl = builtinDecl;
103  BuiltinInfo.ID = builtinID;
104  }
105 
106  public:
107  CGCallee() : KindOrFunctionPointer(SpecialKind::Invalid) {}
108 
109  /// Construct a callee. Call this constructor directly when this
110  /// isn't a direct call.
111  CGCallee(const CGCalleeInfo &abstractInfo, llvm::Value *functionPtr)
112  : KindOrFunctionPointer(SpecialKind(uintptr_t(functionPtr))) {
113  AbstractInfo = abstractInfo;
114  assert(functionPtr && "configuring callee without function pointer");
115  assert(functionPtr->getType()->isPointerTy());
116  assert(functionPtr->getType()->getPointerElementType()->isFunctionTy());
117  }
118 
119  static CGCallee forBuiltin(unsigned builtinID,
120  const FunctionDecl *builtinDecl) {
121  CGCallee result(SpecialKind::Builtin);
122  result.BuiltinInfo.Decl = builtinDecl;
123  result.BuiltinInfo.ID = builtinID;
124  return result;
125  }
126 
128  CGCallee result(SpecialKind::PseudoDestructor);
129  result.PseudoDestructorInfo.Expr = E;
130  return result;
131  }
132 
133  static CGCallee forDirect(llvm::Constant *functionPtr,
134  const CGCalleeInfo &abstractInfo = CGCalleeInfo()) {
135  return CGCallee(abstractInfo, functionPtr);
136  }
137 
138  static CGCallee
139  forDirect(llvm::FunctionCallee functionPtr,
140  const CGCalleeInfo &abstractInfo = CGCalleeInfo()) {
141  return CGCallee(abstractInfo, functionPtr.getCallee());
142  }
143 
144  static CGCallee forVirtual(const CallExpr *CE, GlobalDecl MD, Address Addr,
145  llvm::FunctionType *FTy) {
146  CGCallee result(SpecialKind::Virtual);
147  result.VirtualInfo.CE = CE;
148  result.VirtualInfo.MD = MD;
149  result.VirtualInfo.Addr = Addr;
150  result.VirtualInfo.FTy = FTy;
151  return result;
152  }
153 
154  bool isBuiltin() const {
155  return KindOrFunctionPointer == SpecialKind::Builtin;
156  }
157  const FunctionDecl *getBuiltinDecl() const {
158  assert(isBuiltin());
159  return BuiltinInfo.Decl;
160  }
161  unsigned getBuiltinID() const {
162  assert(isBuiltin());
163  return BuiltinInfo.ID;
164  }
165 
166  bool isPseudoDestructor() const {
167  return KindOrFunctionPointer == SpecialKind::PseudoDestructor;
168  }
170  assert(isPseudoDestructor());
171  return PseudoDestructorInfo.Expr;
172  }
173 
174  bool isOrdinary() const {
175  return uintptr_t(KindOrFunctionPointer) > uintptr_t(SpecialKind::Last);
176  }
178  if (isVirtual())
179  return VirtualInfo.MD;
180  assert(isOrdinary());
181  return AbstractInfo;
182  }
184  assert(isOrdinary());
185  return reinterpret_cast<llvm::Value*>(uintptr_t(KindOrFunctionPointer));
186  }
187  void setFunctionPointer(llvm::Value *functionPtr) {
188  assert(isOrdinary());
189  KindOrFunctionPointer = SpecialKind(uintptr_t(functionPtr));
190  }
191 
192  bool isVirtual() const {
193  return KindOrFunctionPointer == SpecialKind::Virtual;
194  }
195  const CallExpr *getVirtualCallExpr() const {
196  assert(isVirtual());
197  return VirtualInfo.CE;
198  }
200  assert(isVirtual());
201  return VirtualInfo.MD;
202  }
204  assert(isVirtual());
205  return VirtualInfo.Addr;
206  }
207  llvm::FunctionType *getVirtualFunctionType() const {
208  assert(isVirtual());
209  return VirtualInfo.FTy;
210  }
211 
212  /// If this is a delayed callee computation of some sort, prepare
213  /// a concrete callee.
214  CGCallee prepareConcreteCallee(CodeGenFunction &CGF) const;
215  };
216 
217  struct CallArg {
218  private:
219  union {
221  LValue LV; /// The argument is semantically a load from this l-value.
222  };
223  bool HasLV;
224 
225  /// A data-flow flag to make sure getRValue and/or copyInto are not
226  /// called twice for duplicated IR emission.
227  mutable bool IsUsed;
228 
229  public:
232  : RV(rv), HasLV(false), IsUsed(false), Ty(ty) {}
234  : LV(lv), HasLV(true), IsUsed(false), Ty(ty) {}
235  bool hasLValue() const { return HasLV; }
236  QualType getType() const { return Ty; }
237 
238  /// \returns an independent RValue. If the CallArg contains an LValue,
239  /// a temporary copy is returned.
240  RValue getRValue(CodeGenFunction &CGF) const;
241 
243  assert(HasLV && !IsUsed);
244  return LV;
245  }
247  assert(!HasLV && !IsUsed);
248  return RV;
249  }
250  void setRValue(RValue _RV) {
251  assert(!HasLV);
252  RV = _RV;
253  }
254 
255  bool isAggregate() const { return HasLV || RV.isAggregate(); }
256 
257  void copyInto(CodeGenFunction &CGF, Address A) const;
258  };
259 
260  /// CallArgList - Type for representing both the value and type of
261  /// arguments in a call.
262  class CallArgList :
263  public SmallVector<CallArg, 8> {
264  public:
265  CallArgList() : StackBase(nullptr) {}
266 
267  struct Writeback {
268  /// The original argument. Note that the argument l-value
269  /// is potentially null.
271 
272  /// The temporary alloca.
274 
275  /// A value to "use" after the writeback, or null.
277  };
278 
279  struct CallArgCleanup {
281 
282  /// The "is active" insertion point. This instruction is temporary and
283  /// will be removed after insertion.
284  llvm::Instruction *IsActiveIP;
285  };
286 
287  void add(RValue rvalue, QualType type) { push_back(CallArg(rvalue, type)); }
288 
290  push_back(CallArg(LV, type));
291  }
292 
293  /// Add all the arguments from another CallArgList to this one. After doing
294  /// this, the old CallArgList retains its list of arguments, but must not
295  /// be used to emit a call.
296  void addFrom(const CallArgList &other) {
297  insert(end(), other.begin(), other.end());
298  Writebacks.insert(Writebacks.end(),
299  other.Writebacks.begin(), other.Writebacks.end());
300  CleanupsToDeactivate.insert(CleanupsToDeactivate.end(),
301  other.CleanupsToDeactivate.begin(),
302  other.CleanupsToDeactivate.end());
303  assert(!(StackBase && other.StackBase) && "can't merge stackbases");
304  if (!StackBase)
305  StackBase = other.StackBase;
306  }
307 
308  void addWriteback(LValue srcLV, Address temporary,
309  llvm::Value *toUse) {
310  Writeback writeback = { srcLV, temporary, toUse };
311  Writebacks.push_back(writeback);
312  }
313 
314  bool hasWritebacks() const { return !Writebacks.empty(); }
315 
316  typedef llvm::iterator_range<SmallVectorImpl<Writeback>::const_iterator>
318 
320  return writeback_const_range(Writebacks.begin(), Writebacks.end());
321  }
322 
324  llvm::Instruction *IsActiveIP) {
325  CallArgCleanup ArgCleanup;
326  ArgCleanup.Cleanup = Cleanup;
327  ArgCleanup.IsActiveIP = IsActiveIP;
328  CleanupsToDeactivate.push_back(ArgCleanup);
329  }
330 
332  return CleanupsToDeactivate;
333  }
334 
335  void allocateArgumentMemory(CodeGenFunction &CGF);
336  llvm::Instruction *getStackBase() const { return StackBase; }
337  void freeArgumentMemory(CodeGenFunction &CGF) const;
338 
339  /// Returns if we're using an inalloca struct to pass arguments in
340  /// memory.
341  bool isUsingInAlloca() const { return StackBase; }
342 
343  private:
344  SmallVector<Writeback, 1> Writebacks;
345 
346  /// Deactivate these cleanups immediately before making the call. This
347  /// is used to cleanup objects that are owned by the callee once the call
348  /// occurs.
349  SmallVector<CallArgCleanup, 1> CleanupsToDeactivate;
350 
351  /// The stacksave call. It dominates all of the argument evaluation.
352  llvm::CallInst *StackBase;
353  };
354 
355  /// FunctionArgList - Type for representing both the decl and type
356  /// of parameters to a function. The decl must be either a
357  /// ParmVarDecl or ImplicitParamDecl.
358  class FunctionArgList : public SmallVector<const VarDecl*, 16> {
359  };
360 
361  /// ReturnValueSlot - Contains the address where the return value of a
362  /// function can be stored, and whether the address is volatile or not.
364  llvm::PointerIntPair<llvm::Value *, 2, unsigned int> Value;
365  CharUnits Alignment;
366 
367  // Return value slot flags
368  enum Flags {
369  IS_VOLATILE = 0x1,
370  IS_UNUSED = 0x2,
371  };
372 
373  public:
375  ReturnValueSlot(Address Addr, bool IsVolatile, bool IsUnused = false)
376  : Value(Addr.isValid() ? Addr.getPointer() : nullptr,
377  (IsVolatile ? IS_VOLATILE : 0) | (IsUnused ? IS_UNUSED : 0)),
378  Alignment(Addr.isValid() ? Addr.getAlignment() : CharUnits::Zero()) {}
379 
380  bool isNull() const { return !getValue().isValid(); }
381 
382  bool isVolatile() const { return Value.getInt() & IS_VOLATILE; }
383  Address getValue() const { return Address(Value.getPointer(), Alignment); }
384  bool isUnused() const { return Value.getInt() & IS_UNUSED; }
385  };
386 
387 } // end namespace CodeGen
388 } // end namespace clang
389 
390 #endif
ReturnValueSlot - Contains the address where the return value of a function can be stored...
Definition: CGCall.h:363
bool isAggregate() const
Definition: CGCall.h:255
Represents a function declaration or definition.
Definition: Decl.h:1737
static CGCallee forDirect(llvm::FunctionCallee functionPtr, const CGCalleeInfo &abstractInfo=CGCalleeInfo())
Definition: CGCall.h:139
A (possibly-)qualified type.
Definition: Type.h:634
CGCallee(const CGCalleeInfo &abstractInfo, llvm::Value *functionPtr)
Construct a callee.
Definition: CGCall.h:111
DominatorTree GraphTraits specialization so the DominatorTree can be iterable by generic graph iterat...
Definition: Dominators.h:29
C Language Family Type Representation.
static const Builtin::Info BuiltinInfo[]
Definition: Builtins.cpp:20
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:86
void addUncopiedAggregate(LValue LV, QualType type)
Definition: CGCall.h:289
CallArg(LValue lv, QualType ty)
Definition: CGCall.h:233
The l-value was an access to a declared entity or something equivalently strong, like the address of ...
constexpr XRayInstrMask Function
Definition: XRayInstr.h:38
bool hasWritebacks() const
Definition: CGCall.h:314
llvm::Instruction * getStackBase() const
Definition: CGCall.h:336
llvm::Value * getFunctionPointer() const
Definition: CGCall.h:183
Address getValue() const
Definition: CGCall.h:383
void add(RValue rvalue, QualType type)
Definition: CGCall.h:287
CodeGenFunction - This class organizes the per-function state that is used while generating LLVM code...
VirtualInfoStorage VirtualInfo
Definition: CGCall.h:95
EHScopeStack::stable_iterator Cleanup
Definition: CGCall.h:280
bool isUsingInAlloca() const
Returns if we&#39;re using an inalloca struct to pass arguments in memory.
Definition: CGCall.h:341
bool isOrdinary() const
Definition: CGCall.h:174
bool isVirtual() const
Definition: CGCall.h:192
void addArgCleanupDeactivation(EHScopeStack::stable_iterator Cleanup, llvm::Instruction *IsActiveIP)
Definition: CGCall.h:323
const CXXPseudoDestructorExpr * getPseudoDestructorExpr() const
Definition: CGCall.h:169
CharUnits - This is an opaque type for sizes expressed in character units.
Definition: CharUnits.h:37
const FunctionDecl * getBuiltinDecl() const
Definition: CGCall.h:157
void setFunctionPointer(llvm::Value *functionPtr)
Definition: CGCall.h:187
llvm::iterator_range< SmallVectorImpl< Writeback >::const_iterator > writeback_const_range
Definition: CGCall.h:317
QualType getType() const
Definition: CGCall.h:236
const CallExpr * getVirtualCallExpr() const
Definition: CGCall.h:195
Represents a C++ pseudo-destructor (C++ [expr.pseudo]).
Definition: ExprCXX.h:2285
void addFrom(const CallArgList &other)
Add all the arguments from another CallArgList to this one.
Definition: CGCall.h:296
Represents a prototype with parameter type info, e.g.
Definition: Type.h:3692
RValue - This trivial value class is used to represent the result of an expression that is evaluated...
Definition: CGValue.h:38
bool isPseudoDestructor() const
Definition: CGCall.h:166
writeback_const_range writebacks() const
Definition: CGCall.h:319
void addWriteback(LValue srcLV, Address temporary, llvm::Value *toUse)
Definition: CGCall.h:308
PseudoDestructorInfoStorage PseudoDestructorInfo
Definition: CGCall.h:94
Address Temporary
The temporary alloca.
Definition: CGCall.h:273
llvm::Value * ToUse
A value to "use" after the writeback, or null.
Definition: CGCall.h:276
This represents one expression.
Definition: Expr.h:108
CGCalleeInfo(const FunctionProtoType *calleeProtoTy)
Definition: CGCall.h:54
static CGCallee forDirect(llvm::Constant *functionPtr, const CGCalleeInfo &abstractInfo=CGCalleeInfo())
Definition: CGCall.h:133
Address getThisAddress() const
Definition: CGCall.h:203
static SVal getValue(SVal val, SValBuilder &svalBuilder)
BuiltinInfoStorage BuiltinInfo
Definition: CGCall.h:93
CGCalleeInfo AbstractInfo
Definition: CGCall.h:92
__UINTPTR_TYPE__ uintptr_t
An unsigned integer type with the property that any valid pointer to void can be converted to this ty...
Definition: opencl-c.h:89
GlobalDecl - represents a global declaration.
Definition: GlobalDecl.h:34
LValue getKnownLValue() const
Definition: CGCall.h:242
bool isBuiltin() const
Definition: CGCall.h:154
#define false
Definition: stdbool.h:33
A saved depth on the scope stack.
Definition: EHScopeStack.h:106
llvm::FunctionType * getVirtualFunctionType() const
Definition: CGCall.h:207
void setRValue(RValue _RV)
Definition: CGCall.h:250
GlobalDecl getVirtualMethodDecl() const
Definition: CGCall.h:199
An aligned address.
Definition: Address.h:24
All available information about a concrete callee.
Definition: CGCall.h:66
FunctionArgList - Type for representing both the decl and type of parameters to a function...
Definition: CGCall.h:358
Optional< types::ID > Type
llvm::Instruction * IsActiveIP
The "is active" insertion point.
Definition: CGCall.h:284
Dataflow Directional Tag Classes.
CGCalleeInfo(const FunctionProtoType *calleeProtoTy, GlobalDecl calleeDecl)
Definition: CGCall.h:52
LValue Source
The original argument.
Definition: CGCall.h:270
static CGCallee forBuiltin(unsigned builtinID, const FunctionDecl *builtinDecl)
Definition: CGCall.h:119
unsigned getBuiltinID() const
Definition: CGCall.h:161
static CGCallee forPseudoDestructor(const CXXPseudoDestructorExpr *E)
Definition: CGCall.h:127
ReturnValueSlot(Address Addr, bool IsVolatile, bool IsUnused=false)
Definition: CGCall.h:375
RValue getKnownRValue() const
Definition: CGCall.h:246
const GlobalDecl getCalleeDecl() const
Definition: CGCall.h:62
unsigned kind
All of the diagnostics that can be emitted by the frontend.
Definition: DiagnosticIDs.h:60
CallArg(RValue rv, QualType ty)
Definition: CGCall.h:231
static CGCallee forVirtual(const CallExpr *CE, GlobalDecl MD, Address Addr, llvm::FunctionType *FTy)
Definition: CGCall.h:144
CallExpr - Represents a function call (C99 6.5.2.2, C++ [expr.call]).
Definition: Expr.h:2429
bool hasLValue() const
Definition: CGCall.h:235
const FunctionProtoType * getCalleeFunctionProtoType() const
Definition: CGCall.h:59
#define true
Definition: stdbool.h:32
LValue - This represents an lvalue references.
Definition: CGValue.h:166
CGCalleeInfo getAbstractInfo() const
Definition: CGCall.h:177
CallArgList - Type for representing both the value and type of arguments in a call.
Definition: CGCall.h:262
CGCalleeInfo(GlobalDecl calleeDecl)
Definition: CGCall.h:56
Abstract information about a function or function prototype.
Definition: CGCall.h:44
ArrayRef< CallArgCleanup > getCleanupsToDeactivate() const
Definition: CGCall.h:331