clang  10.0.0svn
TargetInfo.h
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1 //===---- TargetInfo.h - Encapsulate target 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_TARGETINFO_H
15 #define LLVM_CLANG_LIB_CODEGEN_TARGETINFO_H
16 
17 #include "CodeGenModule.h"
18 #include "CGValue.h"
19 #include "clang/AST/Type.h"
20 #include "clang/Basic/LLVM.h"
21 #include "clang/Basic/SyncScope.h"
22 #include "llvm/ADT/SmallString.h"
23 #include "llvm/ADT/StringRef.h"
24 
25 namespace llvm {
26 class Constant;
27 class GlobalValue;
28 class Type;
29 class Value;
30 }
31 
32 namespace clang {
33 class Decl;
34 
35 namespace CodeGen {
36 class ABIInfo;
37 class CallArgList;
38 class CodeGenFunction;
39 class CGBlockInfo;
40 class CGFunctionInfo;
41 
42 /// TargetCodeGenInfo - This class organizes various target-specific
43 /// codegeneration issues, like target-specific attributes, builtins and so
44 /// on.
46  ABIInfo *Info;
47 
48 public:
49  // WARNING: Acquires the ownership of ABIInfo.
50  TargetCodeGenInfo(ABIInfo *info = nullptr) : Info(info) {}
51  virtual ~TargetCodeGenInfo();
52 
53  /// getABIInfo() - Returns ABI info helper for the target.
54  const ABIInfo &getABIInfo() const { return *Info; }
55 
56  /// setTargetAttributes - Provides a convenient hook to handle extra
57  /// target-specific attributes for the given global.
58  virtual void setTargetAttributes(const Decl *D, llvm::GlobalValue *GV,
59  CodeGen::CodeGenModule &M) const {}
60 
61  /// emitTargetMD - Provides a convenient hook to handle extra
62  /// target-specific metadata for the given global.
63  virtual void emitTargetMD(const Decl *D, llvm::GlobalValue *GV,
64  CodeGen::CodeGenModule &M) const {}
65 
66  /// Determines the size of struct _Unwind_Exception on this platform,
67  /// in 8-bit units. The Itanium ABI defines this as:
68  /// struct _Unwind_Exception {
69  /// uint64 exception_class;
70  /// _Unwind_Exception_Cleanup_Fn exception_cleanup;
71  /// uint64 private_1;
72  /// uint64 private_2;
73  /// };
74  virtual unsigned getSizeOfUnwindException() const;
75 
76  /// Controls whether __builtin_extend_pointer should sign-extend
77  /// pointers to uint64_t or zero-extend them (the default). Has
78  /// no effect for targets:
79  /// - that have 64-bit pointers, or
80  /// - that cannot address through registers larger than pointers, or
81  /// - that implicitly ignore/truncate the top bits when addressing
82  /// through such registers.
83  virtual bool extendPointerWithSExt() const { return false; }
84 
85  /// Determines the DWARF register number for the stack pointer, for
86  /// exception-handling purposes. Implements __builtin_dwarf_sp_column.
87  ///
88  /// Returns -1 if the operation is unsupported by this target.
90  return -1;
91  }
92 
93  /// Initializes the given DWARF EH register-size table, a char*.
94  /// Implements __builtin_init_dwarf_reg_size_table.
95  ///
96  /// Returns true if the operation is unsupported by this target.
98  llvm::Value *Address) const {
99  return true;
100  }
101 
102  /// Performs the code-generation required to convert a return
103  /// address as stored by the system into the actual address of the
104  /// next instruction that will be executed.
105  ///
106  /// Used by __builtin_extract_return_addr().
108  llvm::Value *Address) const {
109  return Address;
110  }
111 
112  /// Performs the code-generation required to convert the address
113  /// of an instruction into a return address suitable for storage
114  /// by the system in a return slot.
115  ///
116  /// Used by __builtin_frob_return_addr().
118  llvm::Value *Address) const {
119  return Address;
120  }
121 
122  /// Corrects the low-level LLVM type for a given constraint and "usual"
123  /// type.
124  ///
125  /// \returns A pointer to a new LLVM type, possibly the same as the original
126  /// on success; 0 on failure.
128  StringRef Constraint,
129  llvm::Type *Ty) const {
130  return Ty;
131  }
132 
133  /// Adds constraints and types for result registers.
136  std::string &Constraints, std::vector<llvm::Type *> &ResultRegTypes,
137  std::vector<llvm::Type *> &ResultTruncRegTypes,
138  std::vector<CodeGen::LValue> &ResultRegDests, std::string &AsmString,
139  unsigned NumOutputs) const {}
140 
141  /// doesReturnSlotInterfereWithArgs - Return true if the target uses an
142  /// argument slot for an 'sret' type.
143  virtual bool doesReturnSlotInterfereWithArgs() const { return true; }
144 
145  /// Retrieve the address of a function to call immediately before
146  /// calling objc_retainAutoreleasedReturnValue. The
147  /// implementation of objc_autoreleaseReturnValue sniffs the
148  /// instruction stream following its return address to decide
149  /// whether it's a call to objc_retainAutoreleasedReturnValue.
150  /// This can be prohibitively expensive, depending on the
151  /// relocation model, and so on some targets it instead sniffs for
152  /// a particular instruction sequence. This functions returns
153  /// that instruction sequence in inline assembly, which will be
154  /// empty if none is required.
155  virtual StringRef getARCRetainAutoreleasedReturnValueMarker() const {
156  return "";
157  }
158 
159  /// Determine whether a call to objc_retainAutoreleasedReturnValue should be
160  /// marked as 'notail'.
162  return false;
163  }
164 
165  /// Return a constant used by UBSan as a signature to identify functions
166  /// possessing type information, or 0 if the platform is unsupported.
167  virtual llvm::Constant *
169  return nullptr;
170  }
171 
172  /// Determine whether a call to an unprototyped functions under
173  /// the given calling convention should use the variadic
174  /// convention or the non-variadic convention.
175  ///
176  /// There's a good reason to make a platform's variadic calling
177  /// convention be different from its non-variadic calling
178  /// convention: the non-variadic arguments can be passed in
179  /// registers (better for performance), and the variadic arguments
180  /// can be passed on the stack (also better for performance). If
181  /// this is done, however, unprototyped functions *must* use the
182  /// non-variadic convention, because C99 states that a call
183  /// through an unprototyped function type must succeed if the
184  /// function was defined with a non-variadic prototype with
185  /// compatible parameters. Therefore, splitting the conventions
186  /// makes it impossible to call a variadic function through an
187  /// unprototyped type. Since function prototypes came out in the
188  /// late 1970s, this is probably an acceptable trade-off.
189  /// Nonetheless, not all platforms are willing to make it, and in
190  /// particularly x86-64 bends over backwards to make the
191  /// conventions compatible.
192  ///
193  /// The default is false. This is correct whenever:
194  /// - the conventions are exactly the same, because it does not
195  /// matter and the resulting IR will be somewhat prettier in
196  /// certain cases; or
197  /// - the conventions are substantively different in how they pass
198  /// arguments, because in this case using the variadic convention
199  /// will lead to C99 violations.
200  ///
201  /// However, some platforms make the conventions identical except
202  /// for passing additional out-of-band information to a variadic
203  /// function: for example, x86-64 passes the number of SSE
204  /// arguments in %al. On these platforms, it is desirable to
205  /// call unprototyped functions using the variadic convention so
206  /// that unprototyped calls to varargs functions still succeed.
207  ///
208  /// Relatedly, platforms which pass the fixed arguments to this:
209  /// A foo(B, C, D);
210  /// differently than they would pass them to this:
211  /// A foo(B, C, D, ...);
212  /// may need to adjust the debugger-support code in Sema to do the
213  /// right thing when calling a function with no know signature.
214  virtual bool isNoProtoCallVariadic(const CodeGen::CallArgList &args,
215  const FunctionNoProtoType *fnType) const;
216 
217  /// Gets the linker options necessary to link a dependent library on this
218  /// platform.
219  virtual void getDependentLibraryOption(llvm::StringRef Lib,
220  llvm::SmallString<24> &Opt) const;
221 
222  /// Gets the linker options necessary to detect object file mismatches on
223  /// this platform.
224  virtual void getDetectMismatchOption(llvm::StringRef Name,
225  llvm::StringRef Value,
226  llvm::SmallString<32> &Opt) const {}
227 
228  /// Get LLVM calling convention for OpenCL kernel.
229  virtual unsigned getOpenCLKernelCallingConv() const;
230 
231  /// Get target specific null pointer.
232  /// \param T is the LLVM type of the null pointer.
233  /// \param QT is the clang QualType of the null pointer.
234  /// \return ConstantPointerNull with the given type \p T.
235  /// Each target can override it to return its own desired constant value.
236  virtual llvm::Constant *getNullPointer(const CodeGen::CodeGenModule &CGM,
237  llvm::PointerType *T, QualType QT) const;
238 
239  /// Get target favored AST address space of a global variable for languages
240  /// other than OpenCL and CUDA.
241  /// If \p D is nullptr, returns the default target favored address space
242  /// for global variable.
243  virtual LangAS getGlobalVarAddressSpace(CodeGenModule &CGM,
244  const VarDecl *D) const;
245 
246  /// Get the AST address space for alloca.
247  virtual LangAS getASTAllocaAddressSpace() const { return LangAS::Default; }
248 
249  /// Perform address space cast of an expression of pointer type.
250  /// \param V is the LLVM value to be casted to another address space.
251  /// \param SrcAddr is the language address space of \p V.
252  /// \param DestAddr is the targeted language address space.
253  /// \param DestTy is the destination LLVM pointer type.
254  /// \param IsNonNull is the flag indicating \p V is known to be non null.
255  virtual llvm::Value *performAddrSpaceCast(CodeGen::CodeGenFunction &CGF,
256  llvm::Value *V, LangAS SrcAddr,
257  LangAS DestAddr, llvm::Type *DestTy,
258  bool IsNonNull = false) const;
259 
260  /// Perform address space cast of a constant expression of pointer type.
261  /// \param V is the LLVM constant to be casted to another address space.
262  /// \param SrcAddr is the language address space of \p V.
263  /// \param DestAddr is the targeted language address space.
264  /// \param DestTy is the destination LLVM pointer type.
265  virtual llvm::Constant *performAddrSpaceCast(CodeGenModule &CGM,
266  llvm::Constant *V,
267  LangAS SrcAddr, LangAS DestAddr,
268  llvm::Type *DestTy) const;
269 
270  /// Get address space of pointer parameter for __cxa_atexit.
272  return LangAS::Default;
273  }
274 
275  /// Get the syncscope used in LLVM IR.
276  virtual llvm::SyncScope::ID getLLVMSyncScopeID(const LangOptions &LangOpts,
278  llvm::AtomicOrdering Ordering,
279  llvm::LLVMContext &Ctx) const;
280 
281  /// Interface class for filling custom fields of a block literal for OpenCL.
283  public:
284  typedef std::pair<llvm::Value *, StringRef> ValueTy;
287  /// Get the custom field types for OpenCL blocks.
288  virtual llvm::SmallVector<llvm::Type *, 1> getCustomFieldTypes() = 0;
289  /// Get the custom field values for OpenCL blocks.
291  getCustomFieldValues(CodeGenFunction &CGF, const CGBlockInfo &Info) = 0;
292  virtual bool areAllCustomFieldValuesConstant(const CGBlockInfo &Info) = 0;
293  /// Get the custom field values for OpenCL blocks if all values are LLVM
294  /// constants.
296  getCustomFieldValues(CodeGenModule &CGM, const CGBlockInfo &Info) = 0;
297  };
299  return nullptr;
300  }
301 
302  /// Create an OpenCL kernel for an enqueued block. The kernel function is
303  /// a wrapper for the block invoke function with target-specific calling
304  /// convention and ABI as an OpenCL kernel. The wrapper function accepts
305  /// block context and block arguments in target-specific way and calls
306  /// the original block invoke function.
307  virtual llvm::Function *
308  createEnqueuedBlockKernel(CodeGenFunction &CGF,
309  llvm::Function *BlockInvokeFunc,
310  llvm::Value *BlockLiteral) const;
311 
312  /// \return true if the target supports alias from the unmangled name to the
313  /// mangled name of functions declared within an extern "C" region and marked
314  /// as 'used', and having internal linkage.
315  virtual bool shouldEmitStaticExternCAliases() const { return true; }
316 
317  virtual void setCUDAKernelCallingConvention(const FunctionType *&FT) const {}
318 };
319 
320 } // namespace CodeGen
321 } // namespace clang
322 
323 #endif // LLVM_CLANG_LIB_CODEGEN_TARGETINFO_H
A (possibly-)qualified type.
Definition: Type.h:643
Specialize PointerLikeTypeTraits to allow LazyGenerationalUpdatePtr to be placed into a PointerUnion...
Definition: Dominators.h:30
FunctionType - C99 6.7.5.3 - Function Declarators.
Definition: Type.h:3393
C Language Family Type Representation.
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:88
const ABIInfo & getABIInfo() const
getABIInfo() - Returns ABI info helper for the target.
Definition: TargetInfo.h:54
The l-value was an access to a declared entity or something equivalently strong, like the address of ...
virtual bool extendPointerWithSExt() const
Controls whether __builtin_extend_pointer should sign-extend pointers to uint64_t or zero-extend them...
Definition: TargetInfo.h:83
bool ReturnValue(const T &V, APValue &R)
Convers a value to an APValue.
Definition: Interp.h:41
Represents a variable declaration or definition.
Definition: Decl.h:827
virtual StringRef getARCRetainAutoreleasedReturnValueMarker() const
Retrieve the address of a function to call immediately before calling objc_retainAutoreleasedReturnVa...
Definition: TargetInfo.h:155
LangAS
Defines the address space values used by the address space qualifier of QualType. ...
Definition: AddressSpaces.h:25
std::pair< llvm::Value *, StringRef > ValueTy
Definition: TargetInfo.h:284
virtual llvm::Constant * getUBSanFunctionSignature(CodeGen::CodeGenModule &CGM) const
Return a constant used by UBSan as a signature to identify functions possessing type information...
Definition: TargetInfo.h:168
virtual void getDetectMismatchOption(llvm::StringRef Name, llvm::StringRef Value, llvm::SmallString< 32 > &Opt) const
Gets the linker options necessary to detect object file mismatches on this platform.
Definition: TargetInfo.h:224
CodeGenFunction - This class organizes the per-function state that is used while generating LLVM code...
Keeps track of the various options that can be enabled, which controls the dialect of C or C++ that i...
Definition: LangOptions.h:49
Forward-declares and imports various common LLVM datatypes that clang wants to use unqualified...
virtual TargetOpenCLBlockHelper * getTargetOpenCLBlockHelper() const
Definition: TargetInfo.h:298
virtual bool shouldSuppressTailCallsOfRetainAutoreleasedReturnValue() const
Determine whether a call to objc_retainAutoreleasedReturnValue should be marked as &#39;notail&#39;...
Definition: TargetInfo.h:161
Scope - A scope is a transient data structure that is used while parsing the program.
Definition: Scope.h:40
virtual void setCUDAKernelCallingConvention(const FunctionType *&FT) const
Definition: TargetInfo.h:317
Represents a K&R-style &#39;int foo()&#39; function, which has no information available about its arguments...
Definition: Type.h:3688
Interface class for filling custom fields of a block literal for OpenCL.
Definition: TargetInfo.h:282
CGBlockInfo - Information to generate a block literal.
Definition: CGBlocks.h:152
TargetCodeGenInfo(ABIInfo *info=nullptr)
Definition: TargetInfo.h:50
#define V(N, I)
Definition: ASTContext.h:2921
virtual bool shouldEmitStaticExternCAliases() const
Definition: TargetInfo.h:315
virtual bool initDwarfEHRegSizeTable(CodeGen::CodeGenFunction &CGF, llvm::Value *Address) const
Initializes the given DWARF EH register-size table, a char*.
Definition: TargetInfo.h:97
virtual bool doesReturnSlotInterfereWithArgs() const
doesReturnSlotInterfereWithArgs - Return true if the target uses an argument slot for an &#39;sret&#39; type...
Definition: TargetInfo.h:143
SyncScope
Defines synch scope values used internally by clang.
Definition: SyncScope.h:42
An aligned address.
Definition: Address.h:24
TargetCodeGenInfo - This class organizes various target-specific codegeneration issues, like target-specific attributes, builtins and so on.
Definition: TargetInfo.h:45
This class organizes the cross-function state that is used while generating LLVM code.
Optional< types::ID > Type
Dataflow Directional Tag Classes.
virtual void setTargetAttributes(const Decl *D, llvm::GlobalValue *GV, CodeGen::CodeGenModule &M) const
setTargetAttributes - Provides a convenient hook to handle extra target-specific attributes for the g...
Definition: TargetInfo.h:58
virtual void emitTargetMD(const Decl *D, llvm::GlobalValue *GV, CodeGen::CodeGenModule &M) const
emitTargetMD - Provides a convenient hook to handle extra target-specific metadata for the given glob...
Definition: TargetInfo.h:63
virtual LangAS getASTAllocaAddressSpace() const
Get the AST address space for alloca.
Definition: TargetInfo.h:247
Provides definitions for the atomic synchronization scopes.
virtual int getDwarfEHStackPointer(CodeGen::CodeGenModule &M) const
Determines the DWARF register number for the stack pointer, for exception-handling purposes...
Definition: TargetInfo.h:89
virtual llvm::Type * adjustInlineAsmType(CodeGen::CodeGenFunction &CGF, StringRef Constraint, llvm::Type *Ty) const
Corrects the low-level LLVM type for a given constraint and "usual" type.
Definition: TargetInfo.h:127
virtual void addReturnRegisterOutputs(CodeGen::CodeGenFunction &CGF, CodeGen::LValue ReturnValue, std::string &Constraints, std::vector< llvm::Type *> &ResultRegTypes, std::vector< llvm::Type *> &ResultTruncRegTypes, std::vector< CodeGen::LValue > &ResultRegDests, std::string &AsmString, unsigned NumOutputs) const
Adds constraints and types for result registers.
Definition: TargetInfo.h:134
ABIInfo - Target specific hooks for defining how a type should be passed or returned from functions...
Definition: ABIInfo.h:50
virtual LangAS getAddrSpaceOfCxaAtexitPtrParam() const
Get address space of pointer parameter for __cxa_atexit.
Definition: TargetInfo.h:271
virtual llvm::Value * decodeReturnAddress(CodeGen::CodeGenFunction &CGF, llvm::Value *Address) const
Performs the code-generation required to convert a return address as stored by the system into the ac...
Definition: TargetInfo.h:107
LValue - This represents an lvalue references.
Definition: CGValue.h:166
CallArgList - Type for representing both the value and type of arguments in a call.
Definition: CGCall.h:262
virtual llvm::Value * encodeReturnAddress(CodeGen::CodeGenFunction &CGF, llvm::Value *Address) const
Performs the code-generation required to convert the address of an instruction into a return address ...
Definition: TargetInfo.h:117