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-c/Types.h"
19#include "llvm/Support/CBindingWrapping.h"
20#include "llvm/Support/Options.h"
21#include <cstdint>
22#include <memory>
23#include <string>
24
25namespace llvm {
26
27class DiagnosticInfo;
28enum DiagnosticSeverity : char;
29class Function;
30class Instruction;
31class LLVMContextImpl;
32class Module;
33class OptBisect;
34template <typename T> class SmallVectorImpl;
35class SMDiagnostic;
36class StringRef;
37class Twine;
38
39namespace yaml {
40
41class Output;
42
43} // end namespace yaml
44
45/// This is an important class for using LLVM in a threaded context.  It
46/// (opaquely) owns and manages the core "global" data of LLVM's core
47/// infrastructure, including the type and constant uniquing tables.
48/// LLVMContext itself provides no locking guarantees, so you should be careful
49/// to have one context per thread.
50class LLVMContext {
51public:
52  LLVMContextImpl *const pImpl;
53  LLVMContext();
54  LLVMContext(LLVMContext &) = delete;
55  LLVMContext &operator=(const LLVMContext &) = delete;
56  ~LLVMContext();
57
58  // Pinned metadata names, which always have the same value.  This is a
59  // compile-time performance optimization, not a correctness optimization.
60  enum {
61    MD_dbg = 0,                       // "dbg"
62    MD_tbaa = 1,                      // "tbaa"
63    MD_prof = 2,                      // "prof"
64    MD_fpmath = 3,                    // "fpmath"
65    MD_range = 4,                     // "range"
66    MD_tbaa_struct = 5,               // "tbaa.struct"
67    MD_invariant_load = 6,            // "invariant.load"
68    MD_alias_scope = 7,               // "alias.scope"
69    MD_noalias = 8,                   // "noalias",
70    MD_nontemporal = 9,               // "nontemporal"
71    MD_mem_parallel_loop_access = 10, // "llvm.mem.parallel_loop_access"
72    MD_nonnull = 11,                  // "nonnull"
73    MD_dereferenceable = 12,          // "dereferenceable"
74    MD_dereferenceable_or_null = 13,  // "dereferenceable_or_null"
75    MD_make_implicit = 14,            // "make.implicit"
76    MD_unpredictable = 15,            // "unpredictable"
77    MD_invariant_group = 16,          // "invariant.group"
78    MD_align = 17,                    // "align"
79    MD_loop = 18,                     // "llvm.loop"
80    MD_type = 19,                     // "type"
81    MD_section_prefix = 20,           // "section_prefix"
82    MD_absolute_symbol = 21,          // "absolute_symbol"
83    MD_associated = 22,               // "associated"
84  };
85
86  /// Known operand bundle tag IDs, which always have the same value.  All
87  /// operand bundle tags that LLVM has special knowledge of are listed here.
88  /// Additionally, this scheme allows LLVM to efficiently check for specific
89  /// operand bundle tags without comparing strings.
90  enum {
91    OB_deopt = 0,         // "deopt"
92    OB_funclet = 1,       // "funclet"
93    OB_gc_transition = 2, // "gc-transition"
94  };
95
96  /// getMDKindID - Return a unique non-zero ID for the specified metadata kind.
97  /// This ID is uniqued across modules in the current LLVMContext.
98  unsigned getMDKindID(StringRef Name) const;
99
100  /// getMDKindNames - Populate client supplied SmallVector with the name for
101  /// custom metadata IDs registered in this LLVMContext.
102  void getMDKindNames(SmallVectorImpl<StringRef> &Result) const;
103
104  /// getOperandBundleTags - Populate client supplied SmallVector with the
105  /// bundle tags registered in this LLVMContext.  The bundle tags are ordered
106  /// by increasing bundle IDs.
107  /// \see LLVMContext::getOperandBundleTagID
108  void getOperandBundleTags(SmallVectorImpl<StringRef> &Result) const;
109
110  /// getOperandBundleTagID - Maps a bundle tag to an integer ID.  Every bundle
111  /// tag registered with an LLVMContext has an unique ID.
112  uint32_t getOperandBundleTagID(StringRef Tag) const;
113
114  /// Define the GC for a function
115  void setGC(const Function &Fn, std::string GCName);
116
117  /// Return the GC for a function
118  const std::string &getGC(const Function &Fn);
119
120  /// Remove the GC for a function
121  void deleteGC(const Function &Fn);
122
123  /// Return true if the Context runtime configuration is set to discard all
124  /// value names. When true, only GlobalValue names will be available in the
125  /// IR.
126  bool shouldDiscardValueNames() const;
127
128  /// Set the Context runtime configuration to discard all value name (but
129  /// GlobalValue). Clients can use this flag to save memory and runtime,
130  /// especially in release mode.
131  void setDiscardValueNames(bool Discard);
132
133  /// Whether there is a string map for uniquing debug info
134  /// identifiers across the context.  Off by default.
135  bool isODRUniquingDebugTypes() const;
136  void enableDebugTypeODRUniquing();
137  void disableDebugTypeODRUniquing();
138
139  using InlineAsmDiagHandlerTy = void (*)(const SMDiagnostic&, void *Context,
140                                          unsigned LocCookie);
141
142  /// Defines the type of a diagnostic handler.
143  /// \see LLVMContext::setDiagnosticHandler.
144  /// \see LLVMContext::diagnose.
145  using DiagnosticHandlerTy = void (*)(const DiagnosticInfo &DI, void *Context);
146
147  /// Defines the type of a yield callback.
148  /// \see LLVMContext::setYieldCallback.
149  using YieldCallbackTy = void (*)(LLVMContext *Context, void *OpaqueHandle);
150
151  /// setInlineAsmDiagnosticHandler - This method sets a handler that is invoked
152  /// when problems with inline asm are detected by the backend.  The first
153  /// argument is a function pointer and the second is a context pointer that
154  /// gets passed into the DiagHandler.
155  ///
156  /// LLVMContext doesn't take ownership or interpret either of these
157  /// pointers.
158  void setInlineAsmDiagnosticHandler(InlineAsmDiagHandlerTy DiagHandler,
159                                     void *DiagContext = nullptr);
160
161  /// getInlineAsmDiagnosticHandler - Return the diagnostic handler set by
162  /// setInlineAsmDiagnosticHandler.
163  InlineAsmDiagHandlerTy getInlineAsmDiagnosticHandler() const;
164
165  /// getInlineAsmDiagnosticContext - Return the diagnostic context set by
166  /// setInlineAsmDiagnosticHandler.
167  void *getInlineAsmDiagnosticContext() const;
168
169  /// setDiagnosticHandler - This method sets a handler that is invoked
170  /// when the backend needs to report anything to the user.  The first
171  /// argument is a function pointer and the second is a context pointer that
172  /// gets passed into the DiagHandler.  The third argument should be set to
173  /// true if the handler only expects enabled diagnostics.
174  ///
175  /// LLVMContext doesn't take ownership or interpret either of these
176  /// pointers.
177  void setDiagnosticHandler(DiagnosticHandlerTy DiagHandler,
178                            void *DiagContext = nullptr,
179                            bool RespectFilters = false);
180
181  /// getDiagnosticHandler - Return the diagnostic handler set by
182  /// setDiagnosticHandler.
183  DiagnosticHandlerTy getDiagnosticHandler() const;
184
185  /// getDiagnosticContext - Return the diagnostic context set by
186  /// setDiagnosticContext.
187  void *getDiagnosticContext() const;
188
189  /// \brief Return if a code hotness metric should be included in optimization
190  /// diagnostics.
191  bool getDiagnosticHotnessRequested() const;
192  /// \brief Set if a code hotness metric should be included in optimization
193  /// diagnostics.
194  void setDiagnosticHotnessRequested(bool Requested);
195
196  /// \brief Return the YAML file used by the backend to save optimization
197  /// diagnostics.  If null, diagnostics are not saved in a file but only
198  /// emitted via the diagnostic handler.
199  yaml::Output *getDiagnosticsOutputFile();
200  /// Set the diagnostics output file used for optimization diagnostics.
201  ///
202  /// By default or if invoked with null, diagnostics are not saved in a file
203  /// but only emitted via the diagnostic handler.  Even if an output file is
204  /// set, the handler is invoked for each diagnostic message.
205  void setDiagnosticsOutputFile(std::unique_ptr<yaml::Output> F);
206
207  /// \brief Get the prefix that should be printed in front of a diagnostic of
208  ///        the given \p Severity
209  static const char *getDiagnosticMessagePrefix(DiagnosticSeverity Severity);
210
211  /// \brief Report a message to the currently installed diagnostic handler.
212  ///
213  /// This function returns, in particular in the case of error reporting
214  /// (DI.Severity == \a DS_Error), so the caller should leave the compilation
215  /// process in a self-consistent state, even though the generated code
216  /// need not be correct.
217  ///
218  /// The diagnostic message will be implicitly prefixed with a severity keyword
219  /// according to \p DI.getSeverity(), i.e., "error: " for \a DS_Error,
220  /// "warning: " for \a DS_Warning, and "note: " for \a DS_Note.
221  void diagnose(const DiagnosticInfo &DI);
222
223  /// \brief Registers a yield callback with the given context.
224  ///
225  /// The yield callback function may be called by LLVM to transfer control back
226  /// to the client that invoked the LLVM compilation. This can be used to yield
227  /// control of the thread, or perform periodic work needed by the client.
228  /// There is no guaranteed frequency at which callbacks must occur; in fact,
229  /// the client is not guaranteed to ever receive this callback. It is at the
230  /// sole discretion of LLVM to do so and only if it can guarantee that
231  /// suspending the thread won't block any forward progress in other LLVM
232  /// contexts in the same process.
233  ///
234  /// At a suspend point, the state of the current LLVM context is intentionally
235  /// undefined. No assumptions about it can or should be made. Only LLVM
236  /// context API calls that explicitly state that they can be used during a
237  /// yield callback are allowed to be used. Any other API calls into the
238  /// context are not supported until the yield callback function returns
239  /// control to LLVM. Other LLVM contexts are unaffected by this restriction.
240  void setYieldCallback(YieldCallbackTy Callback, void *OpaqueHandle);
241
242  /// \brief Calls the yield callback (if applicable).
243  ///
244  /// This transfers control of the current thread back to the client, which may
245  /// suspend the current thread. Only call this method when LLVM doesn't hold
246  /// any global mutex or cannot block the execution in another LLVM context.
247  void yield();
248
249  /// emitError - Emit an error message to the currently installed error handler
250  /// with optional location information.  This function returns, so code should
251  /// be prepared to drop the erroneous construct on the floor and "not crash".
252  /// The generated code need not be correct.  The error message will be
253  /// implicitly prefixed with "error: " and should not end with a ".".
254  void emitError(unsigned LocCookie, const Twine &ErrorStr);
255  void emitError(const Instruction *I, const Twine &ErrorStr);
256  void emitError(const Twine &ErrorStr);
257
258  /// \brief Query for a debug option's value.
259  ///
260  /// This function returns typed data populated from command line parsing.
261  template <typename ValT, typename Base, ValT(Base::*Mem)>
262  ValT getOption() const {
263    return OptionRegistry::instance().template get<ValT, Base, Mem>();
264  }
265
266  /// \brief Access the object which manages optimization bisection for failure
267  /// analysis.
268  OptBisect &getOptBisect();
269private:
270  // Module needs access to the add/removeModule methods.
271  friend class Module;
272
273  /// addModule - Register a module as being instantiated in this context.  If
274  /// the context is deleted, the module will be deleted as well.
275  void addModule(Module*);
276
277  /// removeModule - Unregister a module from this context.
278  void removeModule(Module*);
279};
280
281// Create wrappers for C Binding types (see CBindingWrapping.h).
282DEFINE_SIMPLE_CONVERSION_FUNCTIONS(LLVMContext, LLVMContextRef)
283
284/* Specialized opaque context conversions.
285 */
286inline LLVMContext **unwrap(LLVMContextRef* Tys) {
287  return reinterpret_cast<LLVMContext**>(Tys);
288}
289
290inline LLVMContextRef *wrap(const LLVMContext **Tys) {
291  return reinterpret_cast<LLVMContextRef*>(const_cast<LLVMContext**>(Tys));
292}
293
294} // end namespace llvm
295
296#endif // LLVM_IR_LLVMCONTEXT_H
297