include/llvm/IR/LLVMContext.h

   1 //===- llvm/LLVMContext.h - Class for managing "global" state ---*- 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 // This file declares LLVMContext, a container of "global" state in LLVM, such
  10 // as the global type and constant uniquing tables.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #ifndef LLVM_IR_LLVMCONTEXT_H
  15 #define LLVM_IR_LLVMCONTEXT_H
  16
  17 #include "llvm-c/Types.h"
  18 #include "llvm/IR/DiagnosticHandler.h"
  19 #include "llvm/Support/CBindingWrapping.h"
  20 #include "llvm/Support/Options.h"
  21 #include <cstdint>
  22 #include <memory>
  23 #include <string>
  24
  25 namespace llvm {
  26
  27 class DiagnosticInfo;
  28 enum DiagnosticSeverity : char;
  29 class Function;
  30 class Instruction;
  31 class LLVMContextImpl;
  32 class Module;
  33 class OptPassGate;
  34 template <typename T> class SmallVectorImpl;
  35 class SMDiagnostic;
  36 class StringRef;
  37 class Twine;
  38 class RemarkStreamer;
  39 class raw_ostream;
  40
  41 namespace SyncScope {
  42
  43 typedef uint8_t ID;
  44
  45 /// Known synchronization scope IDs, which always have the same value.  All
  46 /// synchronization scope IDs that LLVM has special knowledge of are listed
  47 /// here.  Additionally, this scheme allows LLVM to efficiently check for
  48 /// specific synchronization scope ID without comparing strings.
  49 enum {
  50   /// Synchronized with respect to signal handlers executing in the same thread.
  51   SingleThread = 0,
  52
  53   /// Synchronized with respect to all concurrently executing threads.
  54   System = 1
  55 };
  56
  57 } // end namespace SyncScope
  58
  59 /// This is an important class for using LLVM in a threaded context.  It
  60 /// (opaquely) owns and manages the core "global" data of LLVM's core
  61 /// infrastructure, including the type and constant uniquing tables.
  62 /// LLVMContext itself provides no locking guarantees, so you should be careful
  63 /// to have one context per thread.
  64 class LLVMContext {
  65 public:
  66   LLVMContextImpl *const pImpl;
  67   LLVMContext();
  68   LLVMContext(LLVMContext &) = delete;
  69   LLVMContext &operator=(const LLVMContext &) = delete;
  70   ~LLVMContext();
  71
  72   // Pinned metadata names, which always have the same value.  This is a
  73   // compile-time performance optimization, not a correctness optimization.
  74   enum : unsigned {
  75 #define LLVM_FIXED_MD_KIND(EnumID, Name, Value) EnumID = Value,
  76 #include "llvm/IR/FixedMetadataKinds.def"
  77 #undef LLVM_FIXED_MD_KIND
  78   };
  79
  80   /// Known operand bundle tag IDs, which always have the same value.  All
  81   /// operand bundle tags that LLVM has special knowledge of are listed here.
  82   /// Additionally, this scheme allows LLVM to efficiently check for specific
  83   /// operand bundle tags without comparing strings.
  84   enum : unsigned {
  85     OB_deopt = 0,         // "deopt"
  86     OB_funclet = 1,       // "funclet"
  87     OB_gc_transition = 2, // "gc-transition"
  88   };
  89
  90   /// getMDKindID - Return a unique non-zero ID for the specified metadata kind.
  91   /// This ID is uniqued across modules in the current LLVMContext.
  92   unsigned getMDKindID(StringRef Name) const;
  93
  94   /// getMDKindNames - Populate client supplied SmallVector with the name for
  95   /// custom metadata IDs registered in this LLVMContext.
  96   void getMDKindNames(SmallVectorImpl<StringRef> &Result) const;
  97
  98   /// getOperandBundleTags - Populate client supplied SmallVector with the
  99   /// bundle tags registered in this LLVMContext.  The bundle tags are ordered
 100   /// by increasing bundle IDs.
 101   /// \see LLVMContext::getOperandBundleTagID
 102   void getOperandBundleTags(SmallVectorImpl<StringRef> &Result) const;
 103
 104   /// getOperandBundleTagID - Maps a bundle tag to an integer ID.  Every bundle
 105   /// tag registered with an LLVMContext has an unique ID.
 106   uint32_t getOperandBundleTagID(StringRef Tag) const;
 107
 108   /// getOrInsertSyncScopeID - Maps synchronization scope name to
 109   /// synchronization scope ID.  Every synchronization scope registered with
 110   /// LLVMContext has unique ID except pre-defined ones.
 111   SyncScope::ID getOrInsertSyncScopeID(StringRef SSN);
 112
 113   /// getSyncScopeNames - Populates client supplied SmallVector with
 114   /// synchronization scope names registered with LLVMContext.  Synchronization
 115   /// scope names are ordered by increasing synchronization scope IDs.
 116   void getSyncScopeNames(SmallVectorImpl<StringRef> &SSNs) const;
 117
 118   /// Define the GC for a function
 119   void setGC(const Function &Fn, std::string GCName);
 120
 121   /// Return the GC for a function
 122   const std::string &getGC(const Function &Fn);
 123
 124   /// Remove the GC for a function
 125   void deleteGC(const Function &Fn);
 126
 127   /// Return true if the Context runtime configuration is set to discard all
 128   /// value names. When true, only GlobalValue names will be available in the
 129   /// IR.
 130   bool shouldDiscardValueNames() const;
 131
 132   /// Set the Context runtime configuration to discard all value name (but
 133   /// GlobalValue). Clients can use this flag to save memory and runtime,
 134   /// especially in release mode.
 135   void setDiscardValueNames(bool Discard);
 136
 137   /// Whether there is a string map for uniquing debug info
 138   /// identifiers across the context.  Off by default.
 139   bool isODRUniquingDebugTypes() const;
 140   void enableDebugTypeODRUniquing();
 141   void disableDebugTypeODRUniquing();
 142
 143   using InlineAsmDiagHandlerTy = void (*)(const SMDiagnostic&, void *Context,
 144                                           unsigned LocCookie);
 145
 146   /// Defines the type of a yield callback.
 147   /// \see LLVMContext::setYieldCallback.
 148   using YieldCallbackTy = void (*)(LLVMContext *Context, void *OpaqueHandle);
 149
 150   /// setInlineAsmDiagnosticHandler - This method sets a handler that is invoked
 151   /// when problems with inline asm are detected by the backend.  The first
 152   /// argument is a function pointer and the second is a context pointer that
 153   /// gets passed into the DiagHandler.
 154   ///
 155   /// LLVMContext doesn't take ownership or interpret either of these
 156   /// pointers.
 157   void setInlineAsmDiagnosticHandler(InlineAsmDiagHandlerTy DiagHandler,
 158                                      void *DiagContext = nullptr);
 159
 160   /// getInlineAsmDiagnosticHandler - Return the diagnostic handler set by
 161   /// setInlineAsmDiagnosticHandler.
 162   InlineAsmDiagHandlerTy getInlineAsmDiagnosticHandler() const;
 163
 164   /// getInlineAsmDiagnosticContext - Return the diagnostic context set by
 165   /// setInlineAsmDiagnosticHandler.
 166   void *getInlineAsmDiagnosticContext() const;
 167
 168   /// setDiagnosticHandlerCallBack - This method sets a handler call back
 169   /// that is invoked when the backend needs to report anything to the user.
 170   /// The first argument is a function pointer and the second is a context pointer
 171   /// that gets passed into the DiagHandler.  The third argument should be set to
 172   /// true if the handler only expects enabled diagnostics.
 173   ///
 174   /// LLVMContext doesn't take ownership or interpret either of these
 175   /// pointers.
 176   void setDiagnosticHandlerCallBack(
 177       DiagnosticHandler::DiagnosticHandlerTy DiagHandler,
 178       void *DiagContext = nullptr, bool RespectFilters = false);
 179
 180   /// setDiagnosticHandler - This method sets unique_ptr to object of DiagnosticHandler
 181   /// to provide custom diagnostic handling. The first argument is unique_ptr of object
 182   /// of type DiagnosticHandler or a derived of that.   The third argument should be
 183   /// set to true if the handler only expects enabled diagnostics.
 184   ///
 185   /// Ownership of this pointer is moved to LLVMContextImpl.
 186   void setDiagnosticHandler(std::unique_ptr<DiagnosticHandler> &&DH,
 187                             bool RespectFilters = false);
 188
 189   /// getDiagnosticHandlerCallBack - Return the diagnostic handler call back set by
 190   /// setDiagnosticHandlerCallBack.
 191   DiagnosticHandler::DiagnosticHandlerTy getDiagnosticHandlerCallBack() const;
 192
 193   /// getDiagnosticContext - Return the diagnostic context set by
 194   /// setDiagnosticContext.
 195   void *getDiagnosticContext() const;
 196
 197   /// getDiagHandlerPtr - Returns const raw pointer of DiagnosticHandler set by
 198   /// setDiagnosticHandler.
 199   const DiagnosticHandler *getDiagHandlerPtr() const;
 200
 201   /// getDiagnosticHandler - transfers owenership of DiagnosticHandler unique_ptr
 202   /// to caller.
 203   std::unique_ptr<DiagnosticHandler> getDiagnosticHandler();
 204
 205   /// Return if a code hotness metric should be included in optimization
 206   /// diagnostics.
 207   bool getDiagnosticsHotnessRequested() const;
 208   /// Set if a code hotness metric should be included in optimization
 209   /// diagnostics.
 210   void setDiagnosticsHotnessRequested(bool Requested);
 211
 212   /// Return the minimum hotness value a diagnostic would need in order
 213   /// to be included in optimization diagnostics. If there is no minimum, this
 214   /// returns None.
 215   uint64_t getDiagnosticsHotnessThreshold() const;
 216
 217   /// Set the minimum hotness value a diagnostic needs in order to be
 218   /// included in optimization diagnostics.
 219   void setDiagnosticsHotnessThreshold(uint64_t Threshold);
 220
 221   /// Return the streamer used by the backend to save remark diagnostics. If it
 222   /// does not exist, diagnostics are not saved in a file but only emitted via
 223   /// the diagnostic handler.
 224   RemarkStreamer *getRemarkStreamer();
 225   const RemarkStreamer *getRemarkStreamer() const;
 226
 227   /// Set the diagnostics output used for optimization diagnostics.
 228   /// This filename may be embedded in a section for tools to find the
 229   /// diagnostics whenever they're needed.
 230   ///
 231   /// If a remark streamer is already set, it will be replaced with
 232   /// \p RemarkStreamer.
 233   ///
 234   /// By default, diagnostics are not saved in a file but only emitted via the
 235   /// diagnostic handler.  Even if an output file is set, the handler is invoked
 236   /// for each diagnostic message.
 237   void setRemarkStreamer(std::unique_ptr<RemarkStreamer> RemarkStreamer);
 238
 239   /// Get the prefix that should be printed in front of a diagnostic of
 240   ///        the given \p Severity
 241   static const char *getDiagnosticMessagePrefix(DiagnosticSeverity Severity);
 242
 243   /// Report a message to the currently installed diagnostic handler.
 244   ///
 245   /// This function returns, in particular in the case of error reporting
 246   /// (DI.Severity == \a DS_Error), so the caller should leave the compilation
 247   /// process in a self-consistent state, even though the generated code
 248   /// need not be correct.
 249   ///
 250   /// The diagnostic message will be implicitly prefixed with a severity keyword
 251   /// according to \p DI.getSeverity(), i.e., "error: " for \a DS_Error,
 252   /// "warning: " for \a DS_Warning, and "note: " for \a DS_Note.
 253   void diagnose(const DiagnosticInfo &DI);
 254
 255   /// Registers a yield callback with the given context.
 256   ///
 257   /// The yield callback function may be called by LLVM to transfer control back
 258   /// to the client that invoked the LLVM compilation. This can be used to yield
 259   /// control of the thread, or perform periodic work needed by the client.
 260   /// There is no guaranteed frequency at which callbacks must occur; in fact,
 261   /// the client is not guaranteed to ever receive this callback. It is at the
 262   /// sole discretion of LLVM to do so and only if it can guarantee that
 263   /// suspending the thread won't block any forward progress in other LLVM
 264   /// contexts in the same process.
 265   ///
 266   /// At a suspend point, the state of the current LLVM context is intentionally
 267   /// undefined. No assumptions about it can or should be made. Only LLVM
 268   /// context API calls that explicitly state that they can be used during a
 269   /// yield callback are allowed to be used. Any other API calls into the
 270   /// context are not supported until the yield callback function returns
 271   /// control to LLVM. Other LLVM contexts are unaffected by this restriction.
 272   void setYieldCallback(YieldCallbackTy Callback, void *OpaqueHandle);
 273
 274   /// Calls the yield callback (if applicable).
 275   ///
 276   /// This transfers control of the current thread back to the client, which may
 277   /// suspend the current thread. Only call this method when LLVM doesn't hold
 278   /// any global mutex or cannot block the execution in another LLVM context.
 279   void yield();
 280
 281   /// emitError - Emit an error message to the currently installed error handler
 282   /// with optional location information.  This function returns, so code should
 283   /// be prepared to drop the erroneous construct on the floor and "not crash".
 284   /// The generated code need not be correct.  The error message will be
 285   /// implicitly prefixed with "error: " and should not end with a ".".
 286   void emitError(unsigned LocCookie, const Twine &ErrorStr);
 287   void emitError(const Instruction *I, const Twine &ErrorStr);
 288   void emitError(const Twine &ErrorStr);
 289
 290   /// Query for a debug option's value.
 291   ///
 292   /// This function returns typed data populated from command line parsing.
 293   template <typename ValT, typename Base, ValT(Base::*Mem)>
 294   ValT getOption() const {
 295     return OptionRegistry::instance().template get<ValT, Base, Mem>();
 296   }
 297
 298   /// Access the object which can disable optional passes and individual
 299   /// optimizations at compile time.
 300   OptPassGate &getOptPassGate() const;
 301
 302   /// Set the object which can disable optional passes and individual
 303   /// optimizations at compile time.
 304   ///
 305   /// The lifetime of the object must be guaranteed to extend as long as the
 306   /// LLVMContext is used by compilation.
 307   void setOptPassGate(OptPassGate&);
 308
 309 private:
 310   // Module needs access to the add/removeModule methods.
 311   friend class Module;
 312
 313   /// addModule - Register a module as being instantiated in this context.  If
 314   /// the context is deleted, the module will be deleted as well.
 315   void addModule(Module*);
 316
 317   /// removeModule - Unregister a module from this context.
 318   void removeModule(Module*);
 319 };
 320
 321 // Create wrappers for C Binding types (see CBindingWrapping.h).
 322 DEFINE_SIMPLE_CONVERSION_FUNCTIONS(LLVMContext, LLVMContextRef)
 323
 324 /* Specialized opaque context conversions.
 325  */
 326 inline LLVMContext **unwrap(LLVMContextRef* Tys) {
 327   return reinterpret_cast<LLVMContext**>(Tys);
 328 }
 329
 330 inline LLVMContextRef *wrap(const LLVMContext **Tys) {
 331   return reinterpret_cast<LLVMContextRef*>(const_cast<LLVMContext**>(Tys));
 332 }
 333
 334 } // end namespace llvm
 335
 336 #endif // LLVM_IR_LLVMCONTEXT_H