1//===-- llvm/LLVMContext.h - Class for managing "global" state --*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file declares LLVMContext, a container of "global" state in LLVM, such
11// as the global type and constant uniquing tables.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_IR_LLVMCONTEXT_H
16#define LLVM_IR_LLVMCONTEXT_H
17
18#include "llvm/Support/CBindingWrapping.h"
19#include "llvm/Support/Compiler.h"
20#include "llvm/Support/Options.h"
21
22namespace llvm {
23
24class LLVMContextImpl;
25class StringRef;
26class Twine;
27class Instruction;
28class Module;
29class SMDiagnostic;
30class DiagnosticInfo;
31template <typename T> class SmallVectorImpl;
32class Function;
33class DebugLoc;
34
35/// This is an important class for using LLVM in a threaded context.  It
36/// (opaquely) owns and manages the core "global" data of LLVM's core
37/// infrastructure, including the type and constant uniquing tables.
38/// LLVMContext itself provides no locking guarantees, so you should be careful
39/// to have one context per thread.
40class LLVMContext {
41public:
42  LLVMContextImpl *const pImpl;
43  LLVMContext();
44  ~LLVMContext();
45
46  // Pinned metadata names, which always have the same value.  This is a
47  // compile-time performance optimization, not a correctness optimization.
48  enum {
49    MD_dbg = 0,  // "dbg"
50    MD_tbaa = 1, // "tbaa"
51    MD_prof = 2,  // "prof"
52    MD_fpmath = 3,  // "fpmath"
53    MD_range = 4, // "range"
54    MD_tbaa_struct = 5, // "tbaa.struct"
55    MD_invariant_load = 6, // "invariant.load"
56    MD_alias_scope = 7, // "alias.scope"
57    MD_noalias = 8, // "noalias",
58    MD_nontemporal = 9, // "nontemporal"
59    MD_mem_parallel_loop_access = 10, // "llvm.mem.parallel_loop_access"
60    MD_nonnull = 11, // "nonnull"
61    MD_dereferenceable = 12, // "dereferenceable"
62    MD_dereferenceable_or_null = 13, // "dereferenceable_or_null"
63    MD_make_implicit = 14, // "make.implicit"
64    MD_unpredictable = 15, // "unpredictable"
65    MD_invariant_group = 16, // "invariant.group"
66    MD_align = 17 // "align"
67  };
68
69  /// Known operand bundle tag IDs, which always have the same value.  All
70  /// operand bundle tags that LLVM has special knowledge of are listed here.
71  /// Additionally, this scheme allows LLVM to efficiently check for specific
72  /// operand bundle tags without comparing strings.
73  enum {
74    OB_deopt = 0,   // "deopt"
75    OB_funclet = 1, // "funclet"
76  };
77
78  /// getMDKindID - Return a unique non-zero ID for the specified metadata kind.
79  /// This ID is uniqued across modules in the current LLVMContext.
80  unsigned getMDKindID(StringRef Name) const;
81
82  /// getMDKindNames - Populate client supplied SmallVector with the name for
83  /// custom metadata IDs registered in this LLVMContext.
84  void getMDKindNames(SmallVectorImpl<StringRef> &Result) const;
85
86  /// getOperandBundleTags - Populate client supplied SmallVector with the
87  /// bundle tags registered in this LLVMContext.  The bundle tags are ordered
88  /// by increasing bundle IDs.
89  /// \see LLVMContext::getOperandBundleTagID
90  void getOperandBundleTags(SmallVectorImpl<StringRef> &Result) const;
91
92  /// getOperandBundleTagID - Maps a bundle tag to an integer ID.  Every bundle
93  /// tag registered with an LLVMContext has an unique ID.
94  uint32_t getOperandBundleTagID(StringRef Tag) const;
95
96  typedef void (*InlineAsmDiagHandlerTy)(const SMDiagnostic&, void *Context,
97                                         unsigned LocCookie);
98
99  /// Defines the type of a diagnostic handler.
100  /// \see LLVMContext::setDiagnosticHandler.
101  /// \see LLVMContext::diagnose.
102  typedef void (*DiagnosticHandlerTy)(const DiagnosticInfo &DI, void *Context);
103
104  /// Defines the type of a yield callback.
105  /// \see LLVMContext::setYieldCallback.
106  typedef void (*YieldCallbackTy)(LLVMContext *Context, void *OpaqueHandle);
107
108  /// setInlineAsmDiagnosticHandler - This method sets a handler that is invoked
109  /// when problems with inline asm are detected by the backend.  The first
110  /// argument is a function pointer and the second is a context pointer that
111  /// gets passed into the DiagHandler.
112  ///
113  /// LLVMContext doesn't take ownership or interpret either of these
114  /// pointers.
115  void setInlineAsmDiagnosticHandler(InlineAsmDiagHandlerTy DiagHandler,
116                                     void *DiagContext = nullptr);
117
118  /// getInlineAsmDiagnosticHandler - Return the diagnostic handler set by
119  /// setInlineAsmDiagnosticHandler.
120  InlineAsmDiagHandlerTy getInlineAsmDiagnosticHandler() const;
121
122  /// getInlineAsmDiagnosticContext - Return the diagnostic context set by
123  /// setInlineAsmDiagnosticHandler.
124  void *getInlineAsmDiagnosticContext() const;
125
126  /// setDiagnosticHandler - This method sets a handler that is invoked
127  /// when the backend needs to report anything to the user.  The first
128  /// argument is a function pointer and the second is a context pointer that
129  /// gets passed into the DiagHandler.  The third argument should be set to
130  /// true if the handler only expects enabled diagnostics.
131  ///
132  /// LLVMContext doesn't take ownership or interpret either of these
133  /// pointers.
134  void setDiagnosticHandler(DiagnosticHandlerTy DiagHandler,
135                            void *DiagContext = nullptr,
136                            bool RespectFilters = false);
137
138  /// getDiagnosticHandler - Return the diagnostic handler set by
139  /// setDiagnosticHandler.
140  DiagnosticHandlerTy getDiagnosticHandler() const;
141
142  /// getDiagnosticContext - Return the diagnostic context set by
143  /// setDiagnosticContext.
144  void *getDiagnosticContext() const;
145
146  /// \brief Report a message to the currently installed diagnostic handler.
147  ///
148  /// This function returns, in particular in the case of error reporting
149  /// (DI.Severity == \a DS_Error), so the caller should leave the compilation
150  /// process in a self-consistent state, even though the generated code
151  /// need not be correct.
152  ///
153  /// The diagnostic message will be implicitly prefixed with a severity keyword
154  /// according to \p DI.getSeverity(), i.e., "error: " for \a DS_Error,
155  /// "warning: " for \a DS_Warning, and "note: " for \a DS_Note.
156  void diagnose(const DiagnosticInfo &DI);
157
158  /// \brief Registers a yield callback with the given context.
159  ///
160  /// The yield callback function may be called by LLVM to transfer control back
161  /// to the client that invoked the LLVM compilation. This can be used to yield
162  /// control of the thread, or perform periodic work needed by the client.
163  /// There is no guaranteed frequency at which callbacks must occur; in fact,
164  /// the client is not guaranteed to ever receive this callback. It is at the
165  /// sole discretion of LLVM to do so and only if it can guarantee that
166  /// suspending the thread won't block any forward progress in other LLVM
167  /// contexts in the same process.
168  ///
169  /// At a suspend point, the state of the current LLVM context is intentionally
170  /// undefined. No assumptions about it can or should be made. Only LLVM
171  /// context API calls that explicitly state that they can be used during a
172  /// yield callback are allowed to be used. Any other API calls into the
173  /// context are not supported until the yield callback function returns
174  /// control to LLVM. Other LLVM contexts are unaffected by this restriction.
175  void setYieldCallback(YieldCallbackTy Callback, void *OpaqueHandle);
176
177  /// \brief Calls the yield callback (if applicable).
178  ///
179  /// This transfers control of the current thread back to the client, which may
180  /// suspend the current thread. Only call this method when LLVM doesn't hold
181  /// any global mutex or cannot block the execution in another LLVM context.
182  void yield();
183
184  /// emitError - Emit an error message to the currently installed error handler
185  /// with optional location information.  This function returns, so code should
186  /// be prepared to drop the erroneous construct on the floor and "not crash".
187  /// The generated code need not be correct.  The error message will be
188  /// implicitly prefixed with "error: " and should not end with a ".".
189  void emitError(unsigned LocCookie, const Twine &ErrorStr);
190  void emitError(const Instruction *I, const Twine &ErrorStr);
191  void emitError(const Twine &ErrorStr);
192
193  /// \brief Query for a debug option's value.
194  ///
195  /// This function returns typed data populated from command line parsing.
196  template <typename ValT, typename Base, ValT(Base::*Mem)>
197  ValT getOption() const {
198    return OptionRegistry::instance().template get<ValT, Base, Mem>();
199  }
200
201private:
202  LLVMContext(LLVMContext&) = delete;
203  void operator=(LLVMContext&) = delete;
204
205  /// addModule - Register a module as being instantiated in this context.  If
206  /// the context is deleted, the module will be deleted as well.
207  void addModule(Module*);
208
209  /// removeModule - Unregister a module from this context.
210  void removeModule(Module*);
211
212  // Module needs access to the add/removeModule methods.
213  friend class Module;
214};
215
216/// getGlobalContext - Returns a global context.  This is for LLVM clients that
217/// only care about operating on a single thread.
218extern LLVMContext &getGlobalContext();
219
220// Create wrappers for C Binding types (see CBindingWrapping.h).
221DEFINE_SIMPLE_CONVERSION_FUNCTIONS(LLVMContext, LLVMContextRef)
222
223/* Specialized opaque context conversions.
224 */
225inline LLVMContext **unwrap(LLVMContextRef* Tys) {
226  return reinterpret_cast<LLVMContext**>(Tys);
227}
228
229inline LLVMContextRef *wrap(const LLVMContext **Tys) {
230  return reinterpret_cast<LLVMContextRef*>(const_cast<LLVMContext**>(Tys));
231}
232
233}
234
235#endif
236