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"
19#include "clang/AST/ASTFwd.h"
20#include "clang/AST/CanonicalType.h"
21#include "clang/AST/GlobalDecl.h"
22#include "clang/AST/Type.h"
23#include "llvm/ADT/STLForwardCompat.h"
24#include "llvm/IR/Value.h"
25
26namespace llvm {
27class Type;
28class Value;
29} // namespace llvm
30
31namespace clang {
32class Decl;
33class FunctionDecl;
34class TargetOptions;
35class VarDecl;
36
37namespace CodeGen {
38
39/// Abstract information about a function or function prototype.
40class CGCalleeInfo {
41 /// The function prototype of the callee.
42 const FunctionProtoType *CalleeProtoTy;
43 /// The function declaration of the callee.
44 GlobalDecl CalleeDecl;
45
46public:
47 explicit CGCalleeInfo() : CalleeProtoTy(nullptr) {}
48 CGCalleeInfo(const FunctionProtoType *calleeProtoTy, GlobalDecl calleeDecl)
49 : CalleeProtoTy(calleeProtoTy), CalleeDecl(calleeDecl) {}
50 CGCalleeInfo(const FunctionProtoType *calleeProtoTy)
51 : CalleeProtoTy(calleeProtoTy) {}
52 CGCalleeInfo(GlobalDecl calleeDecl)
53 : CalleeProtoTy(nullptr), CalleeDecl(calleeDecl) {}
54
55 const FunctionProtoType *getCalleeFunctionProtoType() const {
56 return CalleeProtoTy;
57 }
58 const GlobalDecl getCalleeDecl() const { return CalleeDecl; }
59};
60
61/// All available information about a concrete callee.
62class CGCallee {
63 enum class SpecialKind : uintptr_t {
64 Invalid,
65 Builtin,
66 PseudoDestructor,
67 Virtual,
68
69 Last = Virtual
70 };
71
72 struct BuiltinInfoStorage {
73 const FunctionDecl *Decl;
74 unsigned ID;
75 };
76 struct PseudoDestructorInfoStorage {
77 const CXXPseudoDestructorExpr *Expr;
78 };
79 struct VirtualInfoStorage {
80 const CallExpr *CE;
81 GlobalDecl MD;
82 Address Addr;
83 llvm::FunctionType *FTy;
84 };
85
86 SpecialKind KindOrFunctionPointer;
87 union {
88 CGCalleeInfo AbstractInfo;
89 BuiltinInfoStorage BuiltinInfo;
90 PseudoDestructorInfoStorage PseudoDestructorInfo;
91 VirtualInfoStorage VirtualInfo;
92 };
93
94 explicit CGCallee(SpecialKind kind) : KindOrFunctionPointer(kind) {}
95
96 CGCallee(const FunctionDecl *builtinDecl, unsigned builtinID)
97 : KindOrFunctionPointer(SpecialKind::Builtin) {
98 BuiltinInfo.Decl = builtinDecl;
99 BuiltinInfo.ID = builtinID;
100 }
101
102public:
103 CGCallee() : KindOrFunctionPointer(SpecialKind::Invalid) {}
104
105 /// Construct a callee. Call this constructor directly when this
106 /// isn't a direct call.
107 CGCallee(const CGCalleeInfo &abstractInfo, llvm::Value *functionPtr)
108 : KindOrFunctionPointer(
109 SpecialKind(reinterpret_cast<uintptr_t>(functionPtr))) {
110 AbstractInfo = abstractInfo;
111 assert(functionPtr && "configuring callee without function pointer");
112 assert(functionPtr->getType()->isPointerTy());
113 }
114
115 static CGCallee forBuiltin(unsigned builtinID,
116 const FunctionDecl *builtinDecl) {
117 CGCallee result(SpecialKind::Builtin);
118 result.BuiltinInfo.Decl = builtinDecl;
119 result.BuiltinInfo.ID = builtinID;
120 return result;
121 }
122
123 static CGCallee forPseudoDestructor(const CXXPseudoDestructorExpr *E) {
124 CGCallee result(SpecialKind::PseudoDestructor);
125 result.PseudoDestructorInfo.Expr = E;
126 return result;
127 }
128
129 static CGCallee forDirect(llvm::Constant *functionPtr,
130 const CGCalleeInfo &abstractInfo = CGCalleeInfo()) {
131 return CGCallee(abstractInfo, functionPtr);
132 }
133
134 static CGCallee forDirect(llvm::FunctionCallee functionPtr,
135 const CGCalleeInfo &abstractInfo = CGCalleeInfo()) {
136 return CGCallee(abstractInfo, functionPtr.getCallee());
137 }
138
139 static CGCallee forVirtual(const CallExpr *CE, GlobalDecl MD, Address Addr,
140 llvm::FunctionType *FTy) {
141 CGCallee result(SpecialKind::Virtual);
142 result.VirtualInfo.CE = CE;
143 result.VirtualInfo.MD = MD;
144 result.VirtualInfo.Addr = Addr;
145 result.VirtualInfo.FTy = FTy;
146 return result;
147 }
148
149 bool isBuiltin() const {
150 return KindOrFunctionPointer == SpecialKind::Builtin;
151 }
152 const FunctionDecl *getBuiltinDecl() const {
153 assert(isBuiltin());
154 return BuiltinInfo.Decl;
155 }
156 unsigned getBuiltinID() const {
157 assert(isBuiltin());
158 return BuiltinInfo.ID;
159 }
160
161 bool isPseudoDestructor() const {
162 return KindOrFunctionPointer == SpecialKind::PseudoDestructor;
163 }
164 const CXXPseudoDestructorExpr *getPseudoDestructorExpr() const {
165 assert(isPseudoDestructor());
166 return PseudoDestructorInfo.Expr;
167 }
168
169 bool isOrdinary() const {
170 return uintptr_t(KindOrFunctionPointer) > uintptr_t(SpecialKind::Last);
171 }
172 CGCalleeInfo getAbstractInfo() const {
173 if (isVirtual())
174 return VirtualInfo.MD;
175 assert(isOrdinary());
176 return AbstractInfo;
177 }
178 llvm::Value *getFunctionPointer() const {
179 assert(isOrdinary());
180 return reinterpret_cast<llvm::Value *>(uintptr_t(KindOrFunctionPointer));
181 }
182 void setFunctionPointer(llvm::Value *functionPtr) {
183 assert(isOrdinary());
184 KindOrFunctionPointer =
185 SpecialKind(reinterpret_cast<uintptr_t>(functionPtr));
186 }
187
188 bool isVirtual() const {
189 return KindOrFunctionPointer == SpecialKind::Virtual;
190 }
191 const CallExpr *getVirtualCallExpr() const {
192 assert(isVirtual());
193 return VirtualInfo.CE;
194 }
195 GlobalDecl getVirtualMethodDecl() const {
196 assert(isVirtual());
197 return VirtualInfo.MD;
198 }
199 Address getThisAddress() const {
200 assert(isVirtual());
201 return VirtualInfo.Addr;
202 }
203 llvm::FunctionType *getVirtualFunctionType() const {
204 assert(isVirtual());
205 return VirtualInfo.FTy;
206 }
207
208 /// If this is a delayed callee computation of some sort, prepare
209 /// a concrete callee.
210 CGCallee prepareConcreteCallee(CodeGenFunction &CGF) const;
211};
212
213struct CallArg {
214private:
215 union {
216 RValue RV;
217 LValue LV; /// The argument is semantically a load from this l-value.
218 };
219 bool HasLV;
220
221 /// A data-flow flag to make sure getRValue and/or copyInto are not
222 /// called twice for duplicated IR emission.
223 mutable bool IsUsed;
224
225public:
226 QualType Ty;
227 CallArg(RValue rv, QualType ty)
228 : RV(rv), HasLV(false), IsUsed(false), Ty(ty) {}
229 CallArg(LValue lv, QualType ty)
230 : LV(lv), HasLV(true), IsUsed(false), Ty(ty) {}
231 bool hasLValue() const { return HasLV; }
232 QualType getType() const { return Ty; }
233
234 /// \returns an independent RValue. If the CallArg contains an LValue,
235 /// a temporary copy is returned.
236 RValue getRValue(CodeGenFunction &CGF) const;
237
238 LValue getKnownLValue() const {
239 assert(HasLV && !IsUsed);
240 return LV;
241 }
242 RValue getKnownRValue() const {
243 assert(!HasLV && !IsUsed);
244 return RV;
245 }
246 void setRValue(RValue _RV) {
247 assert(!HasLV);
248 RV = _RV;
249 }
250
251 bool isAggregate() const { return HasLV || RV.isAggregate(); }
252
253 void copyInto(CodeGenFunction &CGF, Address A) const;
254};
255
256/// CallArgList - Type for representing both the value and type of
257/// arguments in a call.
258class CallArgList : public SmallVector<CallArg, 8> {
259public:
260 CallArgList() = default;
261
262 struct Writeback {
263 /// The original argument. Note that the argument l-value
264 /// is potentially null.
265 LValue Source;
266
267 /// The temporary alloca.
268 Address Temporary;
269
270 /// A value to "use" after the writeback, or null.
271 llvm::Value *ToUse;
272 };
273
274 struct CallArgCleanup {
275 EHScopeStack::stable_iterator Cleanup;
276
277 /// The "is active" insertion point. This instruction is temporary and
278 /// will be removed after insertion.
279 llvm::Instruction *IsActiveIP;
280 };
281
282 void add(RValue rvalue, QualType type) { push_back(Elt: CallArg(rvalue, type)); }
283
284 void addUncopiedAggregate(LValue LV, QualType type) {
285 push_back(Elt: CallArg(LV, type));
286 }
287
288 /// Add all the arguments from another CallArgList to this one. After doing
289 /// this, the old CallArgList retains its list of arguments, but must not
290 /// be used to emit a call.
291 void addFrom(const CallArgList &other) {
292 insert(I: end(), From: other.begin(), To: other.end());
293 Writebacks.insert(I: Writebacks.end(), From: other.Writebacks.begin(),
294 To: other.Writebacks.end());
295 CleanupsToDeactivate.insert(I: CleanupsToDeactivate.end(),
296 From: other.CleanupsToDeactivate.begin(),
297 To: other.CleanupsToDeactivate.end());
298 assert(!(StackBase && other.StackBase) && "can't merge stackbases");
299 if (!StackBase)
300 StackBase = other.StackBase;
301 }
302
303 void addWriteback(LValue srcLV, Address temporary, llvm::Value *toUse) {
304 Writeback writeback = {srcLV, temporary, toUse};
305 Writebacks.push_back(Elt: writeback);
306 }
307
308 bool hasWritebacks() const { return !Writebacks.empty(); }
309
310 typedef llvm::iterator_range<SmallVectorImpl<Writeback>::const_iterator>
311 writeback_const_range;
312
313 writeback_const_range writebacks() const {
314 return writeback_const_range(Writebacks.begin(), Writebacks.end());
315 }
316
317 void addArgCleanupDeactivation(EHScopeStack::stable_iterator Cleanup,
318 llvm::Instruction *IsActiveIP) {
319 CallArgCleanup ArgCleanup;
320 ArgCleanup.Cleanup = Cleanup;
321 ArgCleanup.IsActiveIP = IsActiveIP;
322 CleanupsToDeactivate.push_back(Elt: ArgCleanup);
323 }
324
325 ArrayRef<CallArgCleanup> getCleanupsToDeactivate() const {
326 return CleanupsToDeactivate;
327 }
328
329 void allocateArgumentMemory(CodeGenFunction &CGF);
330 llvm::Instruction *getStackBase() const { return StackBase; }
331 void freeArgumentMemory(CodeGenFunction &CGF) const;
332
333 /// Returns if we're using an inalloca struct to pass arguments in
334 /// memory.
335 bool isUsingInAlloca() const { return StackBase; }
336
337private:
338 SmallVector<Writeback, 1> Writebacks;
339
340 /// Deactivate these cleanups immediately before making the call. This
341 /// is used to cleanup objects that are owned by the callee once the call
342 /// occurs.
343 SmallVector<CallArgCleanup, 1> CleanupsToDeactivate;
344
345 /// The stacksave call. It dominates all of the argument evaluation.
346 llvm::CallInst *StackBase = nullptr;
347};
348
349/// FunctionArgList - Type for representing both the decl and type
350/// of parameters to a function. The decl must be either a
351/// ParmVarDecl or ImplicitParamDecl.
352class FunctionArgList : public SmallVector<const VarDecl *, 16> {};
353
354/// ReturnValueSlot - Contains the address where the return value of a
355/// function can be stored, and whether the address is volatile or not.
356class ReturnValueSlot {
357 Address Addr = Address::invalid();
358
359 // Return value slot flags
360 LLVM_PREFERRED_TYPE(bool)
361 unsigned IsVolatile : 1;
362 LLVM_PREFERRED_TYPE(bool)
363 unsigned IsUnused : 1;
364 LLVM_PREFERRED_TYPE(bool)
365 unsigned IsExternallyDestructed : 1;
366
367public:
368 ReturnValueSlot()
369 : IsVolatile(false), IsUnused(false), IsExternallyDestructed(false) {}
370 ReturnValueSlot(Address Addr, bool IsVolatile, bool IsUnused = false,
371 bool IsExternallyDestructed = false)
372 : Addr(Addr), IsVolatile(IsVolatile), IsUnused(IsUnused),
373 IsExternallyDestructed(IsExternallyDestructed) {}
374
375 bool isNull() const { return !Addr.isValid(); }
376 bool isVolatile() const { return IsVolatile; }
377 Address getValue() const { return Addr; }
378 bool isUnused() const { return IsUnused; }
379 bool isExternallyDestructed() const { return IsExternallyDestructed; }
380};
381
382/// Adds attributes to \p F according to our \p CodeGenOpts and \p LangOpts, as
383/// though we had emitted it ourselves. We remove any attributes on F that
384/// conflict with the attributes we add here.
385///
386/// This is useful for adding attrs to bitcode modules that you want to link
387/// with but don't control, such as CUDA's libdevice. When linking with such
388/// a bitcode library, you might want to set e.g. its functions'
389/// "unsafe-fp-math" attribute to match the attr of the functions you're
390/// codegen'ing. Otherwise, LLVM will interpret the bitcode module's lack of
391/// unsafe-fp-math attrs as tantamount to unsafe-fp-math=false, and then LLVM
392/// will propagate unsafe-fp-math=false up to every transitive caller of a
393/// function in the bitcode library!
394///
395/// With the exception of fast-math attrs, this will only make the attributes
396/// on the function more conservative. But it's unsafe to call this on a
397/// function which relies on particular fast-math attributes for correctness.
398/// It's up to you to ensure that this is safe.
399void mergeDefaultFunctionDefinitionAttributes(llvm::Function &F,
400 const CodeGenOptions &CodeGenOpts,
401 const LangOptions &LangOpts,
402 const TargetOptions &TargetOpts,
403 bool WillInternalize);
404
405enum class FnInfoOpts {
406 None = 0,
407 IsInstanceMethod = 1 << 0,
408 IsChainCall = 1 << 1,
409 IsDelegateCall = 1 << 2,
410};
411
412inline FnInfoOpts operator|(FnInfoOpts A, FnInfoOpts B) {
413 return static_cast<FnInfoOpts>(llvm::to_underlying(E: A) |
414 llvm::to_underlying(E: B));
415}
416
417inline FnInfoOpts operator&(FnInfoOpts A, FnInfoOpts B) {
418 return static_cast<FnInfoOpts>(llvm::to_underlying(E: A) &
419 llvm::to_underlying(E: B));
420}
421
422inline FnInfoOpts operator|=(FnInfoOpts A, FnInfoOpts B) {
423 A = A | B;
424 return A;
425}
426
427inline FnInfoOpts operator&=(FnInfoOpts A, FnInfoOpts B) {
428 A = A & B;
429 return A;
430}
431
432} // end namespace CodeGen
433} // end namespace clang
434
435#endif
436

source code of clang/lib/CodeGen/CGCall.h