clang  10.0.0git
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 } // namespace llvm
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 forDirect(llvm::FunctionCallee functionPtr,
139  const CGCalleeInfo &abstractInfo = CGCalleeInfo()) {
140  return CGCallee(abstractInfo, functionPtr.getCallee());
141  }
142 
143  static CGCallee forVirtual(const CallExpr *CE, GlobalDecl MD, Address Addr,
144  llvm::FunctionType *FTy) {
145  CGCallee result(SpecialKind::Virtual);
146  result.VirtualInfo.CE = CE;
147  result.VirtualInfo.MD = MD;
148  result.VirtualInfo.Addr = Addr;
149  result.VirtualInfo.FTy = FTy;
150  return result;
151  }
152 
153  bool isBuiltin() const {
154  return KindOrFunctionPointer == SpecialKind::Builtin;
155  }
156  const FunctionDecl *getBuiltinDecl() const {
157  assert(isBuiltin());
158  return BuiltinInfo.Decl;
159  }
160  unsigned getBuiltinID() const {
161  assert(isBuiltin());
162  return BuiltinInfo.ID;
163  }
164 
165  bool isPseudoDestructor() const {
166  return KindOrFunctionPointer == SpecialKind::PseudoDestructor;
167  }
169  assert(isPseudoDestructor());
170  return PseudoDestructorInfo.Expr;
171  }
172 
173  bool isOrdinary() const {
174  return uintptr_t(KindOrFunctionPointer) > uintptr_t(SpecialKind::Last);
175  }
177  if (isVirtual())
178  return VirtualInfo.MD;
179  assert(isOrdinary());
180  return AbstractInfo;
181  }
183  assert(isOrdinary());
184  return reinterpret_cast<llvm::Value *>(uintptr_t(KindOrFunctionPointer));
185  }
186  void setFunctionPointer(llvm::Value *functionPtr) {
187  assert(isOrdinary());
188  KindOrFunctionPointer = SpecialKind(uintptr_t(functionPtr));
189  }
190 
191  bool isVirtual() const {
192  return KindOrFunctionPointer == SpecialKind::Virtual;
193  }
194  const CallExpr *getVirtualCallExpr() const {
195  assert(isVirtual());
196  return VirtualInfo.CE;
197  }
199  assert(isVirtual());
200  return VirtualInfo.MD;
201  }
203  assert(isVirtual());
204  return VirtualInfo.Addr;
205  }
206  llvm::FunctionType *getVirtualFunctionType() const {
207  assert(isVirtual());
208  return VirtualInfo.FTy;
209  }
210 
211  /// If this is a delayed callee computation of some sort, prepare
212  /// a concrete callee.
213  CGCallee prepareConcreteCallee(CodeGenFunction &CGF) const;
214 };
215 
216 struct CallArg {
217 private:
218  union {
220  LValue LV; /// The argument is semantically a load from this l-value.
221  };
222  bool HasLV;
223 
224  /// A data-flow flag to make sure getRValue and/or copyInto are not
225  /// called twice for duplicated IR emission.
226  mutable bool IsUsed;
227 
228 public:
231  : RV(rv), HasLV(false), IsUsed(false), Ty(ty) {}
233  : LV(lv), HasLV(true), IsUsed(false), Ty(ty) {}
234  bool hasLValue() const { return HasLV; }
235  QualType getType() const { return Ty; }
236 
237  /// \returns an independent RValue. If the CallArg contains an LValue,
238  /// a temporary copy is returned.
239  RValue getRValue(CodeGenFunction &CGF) const;
240 
242  assert(HasLV && !IsUsed);
243  return LV;
244  }
246  assert(!HasLV && !IsUsed);
247  return RV;
248  }
249  void setRValue(RValue _RV) {
250  assert(!HasLV);
251  RV = _RV;
252  }
253 
254  bool isAggregate() const { return HasLV || RV.isAggregate(); }
255 
256  void copyInto(CodeGenFunction &CGF, Address A) const;
257 };
258 
259 /// CallArgList - Type for representing both the value and type of
260 /// arguments in a call.
261 class CallArgList : public SmallVector<CallArg, 8> {
262 public:
263  CallArgList() : StackBase(nullptr) {}
264 
265  struct Writeback {
266  /// The original argument. Note that the argument l-value
267  /// is potentially null.
269 
270  /// The temporary alloca.
272 
273  /// A value to "use" after the writeback, or null.
275  };
276 
277  struct CallArgCleanup {
279 
280  /// The "is active" insertion point. This instruction is temporary and
281  /// will be removed after insertion.
282  llvm::Instruction *IsActiveIP;
283  };
284 
285  void add(RValue rvalue, QualType type) { push_back(CallArg(rvalue, type)); }
286 
288  push_back(CallArg(LV, type));
289  }
290 
291  /// Add all the arguments from another CallArgList to this one. After doing
292  /// this, the old CallArgList retains its list of arguments, but must not
293  /// be used to emit a call.
294  void addFrom(const CallArgList &other) {
295  insert(end(), other.begin(), other.end());
296  Writebacks.insert(Writebacks.end(), other.Writebacks.begin(),
297  other.Writebacks.end());
298  CleanupsToDeactivate.insert(CleanupsToDeactivate.end(),
299  other.CleanupsToDeactivate.begin(),
300  other.CleanupsToDeactivate.end());
301  assert(!(StackBase && other.StackBase) && "can't merge stackbases");
302  if (!StackBase)
303  StackBase = other.StackBase;
304  }
305 
306  void addWriteback(LValue srcLV, Address temporary, llvm::Value *toUse) {
307  Writeback writeback = {srcLV, temporary, toUse};
308  Writebacks.push_back(writeback);
309  }
310 
311  bool hasWritebacks() const { return !Writebacks.empty(); }
312 
313  typedef llvm::iterator_range<SmallVectorImpl<Writeback>::const_iterator>
315 
317  return writeback_const_range(Writebacks.begin(), Writebacks.end());
318  }
319 
321  llvm::Instruction *IsActiveIP) {
322  CallArgCleanup ArgCleanup;
323  ArgCleanup.Cleanup = Cleanup;
324  ArgCleanup.IsActiveIP = IsActiveIP;
325  CleanupsToDeactivate.push_back(ArgCleanup);
326  }
327 
329  return CleanupsToDeactivate;
330  }
331 
332  void allocateArgumentMemory(CodeGenFunction &CGF);
333  llvm::Instruction *getStackBase() const { return StackBase; }
334  void freeArgumentMemory(CodeGenFunction &CGF) const;
335 
336  /// Returns if we're using an inalloca struct to pass arguments in
337  /// memory.
338  bool isUsingInAlloca() const { return StackBase; }
339 
340 private:
341  SmallVector<Writeback, 1> Writebacks;
342 
343  /// Deactivate these cleanups immediately before making the call. This
344  /// is used to cleanup objects that are owned by the callee once the call
345  /// occurs.
346  SmallVector<CallArgCleanup, 1> CleanupsToDeactivate;
347 
348  /// The stacksave call. It dominates all of the argument evaluation.
349  llvm::CallInst *StackBase;
350 };
351 
352 /// FunctionArgList - Type for representing both the decl and type
353 /// of parameters to a function. The decl must be either a
354 /// ParmVarDecl or ImplicitParamDecl.
355 class FunctionArgList : public SmallVector<const VarDecl *, 16> {};
356 
357 /// ReturnValueSlot - Contains the address where the return value of a
358 /// function can be stored, and whether the address is volatile or not.
360  llvm::PointerIntPair<llvm::Value *, 2, unsigned int> Value;
361  CharUnits Alignment;
362 
363  // Return value slot flags
364  enum Flags {
365  IS_VOLATILE = 0x1,
366  IS_UNUSED = 0x2,
367  };
368 
369 public:
371  ReturnValueSlot(Address Addr, bool IsVolatile, bool IsUnused = false)
372  : Value(Addr.isValid() ? Addr.getPointer() : nullptr,
373  (IsVolatile ? IS_VOLATILE : 0) | (IsUnused ? IS_UNUSED : 0)),
374  Alignment(Addr.isValid() ? Addr.getAlignment() : CharUnits::Zero()) {}
375 
376  bool isNull() const { return !getValue().isValid(); }
377 
378  bool isVolatile() const { return Value.getInt() & IS_VOLATILE; }
379  Address getValue() const { return Address(Value.getPointer(), Alignment); }
380  bool isUnused() const { return Value.getInt() & IS_UNUSED; }
381 };
382 
383 } // end namespace CodeGen
384 } // end namespace clang
385 
386 #endif
ReturnValueSlot - Contains the address where the return value of a function can be stored...
Definition: CGCall.h:359
bool isAggregate() const
Definition: CGCall.h:254
Represents a function declaration or definition.
Definition: Decl.h:1783
static CGCallee forDirect(llvm::FunctionCallee functionPtr, const CGCalleeInfo &abstractInfo=CGCalleeInfo())
Definition: CGCall.h:138
A (possibly-)qualified type.
Definition: Type.h:654
CGCallee(const CGCalleeInfo &abstractInfo, llvm::Value *functionPtr)
Construct a callee.
Definition: CGCall.h:111
Specialize PointerLikeTypeTraits to allow LazyGenerationalUpdatePtr to be placed into a PointerUnion...
Definition: Dominators.h:30
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:88
void addUncopiedAggregate(LValue LV, QualType type)
Definition: CGCall.h:287
CallArg(LValue lv, QualType ty)
Definition: CGCall.h:232
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:311
llvm::Instruction * getStackBase() const
Definition: CGCall.h:333
llvm::Value * getFunctionPointer() const
Definition: CGCall.h:182
Address getValue() const
Definition: CGCall.h:379
void add(RValue rvalue, QualType type)
Definition: CGCall.h:285
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:278
bool isUsingInAlloca() const
Returns if we&#39;re using an inalloca struct to pass arguments in memory.
Definition: CGCall.h:338
bool Zero(InterpState &S, CodePtr OpPC)
Definition: Interp.h:812
bool isOrdinary() const
Definition: CGCall.h:173
bool isVirtual() const
Definition: CGCall.h:191
void addArgCleanupDeactivation(EHScopeStack::stable_iterator Cleanup, llvm::Instruction *IsActiveIP)
Definition: CGCall.h:320
const CXXPseudoDestructorExpr * getPseudoDestructorExpr() const
Definition: CGCall.h:168
CharUnits - This is an opaque type for sizes expressed in character units.
Definition: CharUnits.h:38
const FunctionDecl * getBuiltinDecl() const
Definition: CGCall.h:156
void setFunctionPointer(llvm::Value *functionPtr)
Definition: CGCall.h:186
llvm::iterator_range< SmallVectorImpl< Writeback >::const_iterator > writeback_const_range
Definition: CGCall.h:314
QualType getType() const
Definition: CGCall.h:235
const CallExpr * getVirtualCallExpr() const
Definition: CGCall.h:194
Represents a C++ pseudo-destructor (C++ [expr.pseudo]).
Definition: ExprCXX.h:2479
void addFrom(const CallArgList &other)
Add all the arguments from another CallArgList to this one.
Definition: CGCall.h:294
Represents a prototype with parameter type info, e.g.
Definition: Type.h:3754
RValue - This trivial value class is used to represent the result of an expression that is evaluated...
Definition: CGValue.h:39
bool isPseudoDestructor() const
Definition: CGCall.h:165
writeback_const_range writebacks() const
Definition: CGCall.h:316
void addWriteback(LValue srcLV, Address temporary, llvm::Value *toUse)
Definition: CGCall.h:306
PseudoDestructorInfoStorage PseudoDestructorInfo
Definition: CGCall.h:94
Address Temporary
The temporary alloca.
Definition: CGCall.h:271
llvm::Value * ToUse
A value to "use" after the writeback, or null.
Definition: CGCall.h:274
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
__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-base.h:62
Address getThisAddress() const
Definition: CGCall.h:202
static SVal getValue(SVal val, SValBuilder &svalBuilder)
BuiltinInfoStorage BuiltinInfo
Definition: CGCall.h:93
CGCalleeInfo AbstractInfo
Definition: CGCall.h:92
GlobalDecl - represents a global declaration.
Definition: GlobalDecl.h:40
LValue getKnownLValue() const
Definition: CGCall.h:241
bool isBuiltin() const
Definition: CGCall.h:153
#define false
Definition: stdbool.h:17
A saved depth on the scope stack.
Definition: EHScopeStack.h:106
llvm::FunctionType * getVirtualFunctionType() const
Definition: CGCall.h:206
void setRValue(RValue _RV)
Definition: CGCall.h:249
GlobalDecl getVirtualMethodDecl() const
Definition: CGCall.h:198
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:355
Optional< types::ID > Type
llvm::Instruction * IsActiveIP
The "is active" insertion point.
Definition: CGCall.h:282
Dataflow Directional Tag Classes.
CGCalleeInfo(const FunctionProtoType *calleeProtoTy, GlobalDecl calleeDecl)
Definition: CGCall.h:52
LValue Source
The original argument.
Definition: CGCall.h:268
static CGCallee forBuiltin(unsigned builtinID, const FunctionDecl *builtinDecl)
Definition: CGCall.h:119
unsigned getBuiltinID() const
Definition: CGCall.h:160
static CGCallee forPseudoDestructor(const CXXPseudoDestructorExpr *E)
Definition: CGCall.h:127
ReturnValueSlot(Address Addr, bool IsVolatile, bool IsUnused=false)
Definition: CGCall.h:371
RValue getKnownRValue() const
Definition: CGCall.h:245
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:230
static CGCallee forVirtual(const CallExpr *CE, GlobalDecl MD, Address Addr, llvm::FunctionType *FTy)
Definition: CGCall.h:143
CallExpr - Represents a function call (C99 6.5.2.2, C++ [expr.call]).
Definition: Expr.h:2546
bool hasLValue() const
Definition: CGCall.h:234
const FunctionProtoType * getCalleeFunctionProtoType() const
Definition: CGCall.h:59
#define true
Definition: stdbool.h:16
LValue - This represents an lvalue references.
Definition: CGValue.h:167
CGCalleeInfo getAbstractInfo() const
Definition: CGCall.h:176
CallArgList - Type for representing both the value and type of arguments in a call.
Definition: CGCall.h:261
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:328