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      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/Compiler.h"
     19 
     20 namespace llvm {
     21 
     22 class LLVMContextImpl;
     23 class StringRef;
     24 class Twine;
     25 class Instruction;
     26 class Module;
     27 class SMDiagnostic;
     28 template <typename T> class SmallVectorImpl;
     29 
     30 /// This is an important class for using LLVM in a threaded context.  It
     31 /// (opaquely) owns and manages the core "global" data of LLVM's core
     32 /// infrastructure, including the type and constant uniquing tables.
     33 /// LLVMContext itself provides no locking guarantees, so you should be careful
     34 /// to have one context per thread.
     35 class LLVMContext {
     36 public:
     37   LLVMContextImpl *const pImpl;
     38   LLVMContext();
     39   ~LLVMContext();
     40 
     41   // Pinned metadata names, which always have the same value.  This is a
     42   // compile-time performance optimization, not a correctness optimization.
     43   enum {
     44     MD_dbg = 0,  // "dbg"
     45     MD_tbaa = 1, // "tbaa"
     46     MD_prof = 2,  // "prof"
     47     MD_fpmath = 3,  // "fpmath"
     48     MD_range = 4, // "range"
     49     MD_tbaa_struct = 5, // "tbaa.struct"
     50     MD_invariant_load = 6 // "invariant.load"
     51   };
     52 
     53   /// getMDKindID - Return a unique non-zero ID for the specified metadata kind.
     54   /// This ID is uniqued across modules in the current LLVMContext.
     55   unsigned getMDKindID(StringRef Name) const;
     56 
     57   /// getMDKindNames - Populate client supplied SmallVector with the name for
     58   /// custom metadata IDs registered in this LLVMContext.
     59   void getMDKindNames(SmallVectorImpl<StringRef> &Result) const;
     60 
     61 
     62   typedef void (*InlineAsmDiagHandlerTy)(const SMDiagnostic&, void *Context,
     63                                          unsigned LocCookie);
     64 
     65   /// setInlineAsmDiagnosticHandler - This method sets a handler that is invoked
     66   /// when problems with inline asm are detected by the backend.  The first
     67   /// argument is a function pointer and the second is a context pointer that
     68   /// gets passed into the DiagHandler.
     69   ///
     70   /// LLVMContext doesn't take ownership or interpret either of these
     71   /// pointers.
     72   void setInlineAsmDiagnosticHandler(InlineAsmDiagHandlerTy DiagHandler,
     73                                      void *DiagContext = 0);
     74 
     75   /// getInlineAsmDiagnosticHandler - Return the diagnostic handler set by
     76   /// setInlineAsmDiagnosticHandler.
     77   InlineAsmDiagHandlerTy getInlineAsmDiagnosticHandler() const;
     78 
     79   /// getInlineAsmDiagnosticContext - Return the diagnostic context set by
     80   /// setInlineAsmDiagnosticHandler.
     81   void *getInlineAsmDiagnosticContext() const;
     82 
     83 
     84   /// emitError - Emit an error message to the currently installed error handler
     85   /// with optional location information.  This function returns, so code should
     86   /// be prepared to drop the erroneous construct on the floor and "not crash".
     87   /// The generated code need not be correct.  The error message will be
     88   /// implicitly prefixed with "error: " and should not end with a ".".
     89   void emitError(unsigned LocCookie, const Twine &ErrorStr);
     90   void emitError(const Instruction *I, const Twine &ErrorStr);
     91   void emitError(const Twine &ErrorStr);
     92 
     93 private:
     94   LLVMContext(LLVMContext&) LLVM_DELETED_FUNCTION;
     95   void operator=(LLVMContext&) LLVM_DELETED_FUNCTION;
     96 
     97   /// addModule - Register a module as being instantiated in this context.  If
     98   /// the context is deleted, the module will be deleted as well.
     99   void addModule(Module*);
    100 
    101   /// removeModule - Unregister a module from this context.
    102   void removeModule(Module*);
    103 
    104   // Module needs access to the add/removeModule methods.
    105   friend class Module;
    106 };
    107 
    108 /// getGlobalContext - Returns a global context.  This is for LLVM clients that
    109 /// only care about operating on a single thread.
    110 extern LLVMContext &getGlobalContext();
    111 
    112 }
    113 
    114 #endif
    115