CGCall.h source code [clang_source_code/lib/CodeGen/CGCall.h]

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/CanonicalType.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() {}
56	CGCalleeInfo(GlobalDecl calleeDecl)
57	: CalleeProtoTy(nullptr), CalleeDecl(calleeDecl) {}
58
59	const FunctionProtoType *getCalleeFunctionProtoType() const {
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 {
81	const CXXPseudoDestructorExpr *Expr;
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 {
92	CGCalleeInfo AbstractInfo;
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	(0) . __assert_fail ("functionPtr && \"configuring callee without function pointer\"", "/home/seafit/code_projects/clang_source/clang/lib/CodeGen/CGCall.h", 114, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">assert(functionPtr && "configuring callee without function pointer");
115	getType()->isPointerTy()", "/home/seafit/code_projects/clang_source/clang/lib/CodeGen/CGCall.h", 115, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">assert(functionPtr->getType()->isPointerTy());
116	getType()->getPointerElementType()->isFunctionTy()", "/home/seafit/code_projects/clang_source/clang/lib/CodeGen/CGCall.h", 116, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">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
127	static CGCallee forPseudoDestructor(const CXXPseudoDestructorExpr *E) {
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	}
169	const CXXPseudoDestructorExpr *getPseudoDestructorExpr() const {
170	assert(isPseudoDestructor());
171	return PseudoDestructorInfo.Expr;
172	}
173
174	bool isOrdinary() const {
175	return uintptr_t(KindOrFunctionPointer) > uintptr_t(SpecialKind::Last);
176	}
177	CGCalleeInfo getAbstractInfo() const {
178	if (isVirtual())
179	return VirtualInfo.MD;
180	assert(isOrdinary());
181	return AbstractInfo;
182	}
183	llvm::Value *getFunctionPointer() const {
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	}
199	GlobalDecl getVirtualMethodDecl() const {
200	assert(isVirtual());
201	return VirtualInfo.MD;
202	}
203	Address getThisAddress() const {
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 {
220	RValue RV;
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:
230	QualType Ty;
231	CallArg(RValue rv, QualType ty)
232	: RV(rv), HasLV(false), IsUsed(false), Ty(ty) {}
233	CallArg(LValue lv, QualType 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
242	LValue getKnownLValue() const {
243	assert(HasLV && !IsUsed);
244	return LV;
245	}
246	RValue getKnownRValue() const {
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.
270	LValue Source;
271
272	/// The temporary alloca.
273	Address Temporary;
274
275	/// A value to "use" after the writeback, or null.
276	llvm::Value *ToUse;
277	};
278
279	struct CallArgCleanup {
280	EHScopeStack::stable_iterator Cleanup;
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
289	void addUncopiedAggregate(LValue LV, QualType type) {
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	(0) . __assert_fail ("!(StackBase && other.StackBase) && \"can't merge stackbases\"", "/home/seafit/code_projects/clang_source/clang/lib/CodeGen/CGCall.h", 303, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">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>
317	writeback_const_range;
318
319	writeback_const_range writebacks() const {
320	return writeback_const_range(Writebacks.begin(), Writebacks.end());
321	}
322
323	void addArgCleanupDeactivation(EHScopeStack::stable_iterator Cleanup,
324	llvm::Instruction *IsActiveIP) {
325	CallArgCleanup ArgCleanup;
326	ArgCleanup.Cleanup = Cleanup;
327	ArgCleanup.IsActiveIP = IsActiveIP;
328	CleanupsToDeactivate.push_back(ArgCleanup);
329	}
330
331	ArrayRef<CallArgCleanup> getCleanupsToDeactivate() const {
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.
363	class ReturnValueSlot {
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:
374	ReturnValueSlot() {}
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
391