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/Core.h"
19#include "llvm/Support/CBindingWrapping.h"
20#include "llvm/Support/Compiler.h"
21#include "llvm/Support/Options.h"
22
23namespace llvm {
24
25class LLVMContextImpl;
26class StringRef;
27class Twine;
28class Instruction;
29class Module;
30class SMDiagnostic;
31class DiagnosticInfo;
32template <typename T> class SmallVectorImpl;
33class Function;
34class DebugLoc;
35
36/// This is an important class for using LLVM in a threaded context.  It
37/// (opaquely) owns and manages the core "global" data of LLVM's core
38/// infrastructure, including the type and constant uniquing tables.
39/// LLVMContext itself provides no locking guarantees, so you should be careful
40/// to have one context per thread.
41class LLVMContext {
42public:
43  LLVMContextImpl *const pImpl;
44  LLVMContext();
45  ~LLVMContext();
46
47  // Pinned metadata names, which always have the same value.  This is a
48  // compile-time performance optimization, not a correctness optimization.
49  enum {
50    MD_dbg = 0,  // "dbg"
51    MD_tbaa = 1, // "tbaa"
52    MD_prof = 2,  // "prof"
53    MD_fpmath = 3,  // "fpmath"
54    MD_range = 4, // "range"
55    MD_tbaa_struct = 5, // "tbaa.struct"
56    MD_invariant_load = 6, // "invariant.load"
57    MD_alias_scope = 7, // "alias.scope"
58    MD_noalias = 8, // "noalias",
59    MD_nontemporal = 9, // "nontemporal"
60    MD_mem_parallel_loop_access = 10, // "llvm.mem.parallel_loop_access"
61    MD_nonnull = 11 // "nonnull"
62  };
63
64  /// getMDKindID - Return a unique non-zero ID for the specified metadata kind.
65  /// This ID is uniqued across modules in the current LLVMContext.
66  unsigned getMDKindID(StringRef Name) const;
67
68  /// getMDKindNames - Populate client supplied SmallVector with the name for
69  /// custom metadata IDs registered in this LLVMContext.
70  void getMDKindNames(SmallVectorImpl<StringRef> &Result) const;
71
72
73  typedef void (*InlineAsmDiagHandlerTy)(const SMDiagnostic&, void *Context,
74                                         unsigned LocCookie);
75
76  /// Defines the type of a diagnostic handler.
77  /// \see LLVMContext::setDiagnosticHandler.
78  /// \see LLVMContext::diagnose.
79  typedef void (*DiagnosticHandlerTy)(const DiagnosticInfo &DI, void *Context);
80
81  /// Defines the type of a yield callback.
82  /// \see LLVMContext::setYieldCallback.
83  typedef void (*YieldCallbackTy)(LLVMContext *Context, void *OpaqueHandle);
84
85  /// setInlineAsmDiagnosticHandler - This method sets a handler that is invoked
86  /// when problems with inline asm are detected by the backend.  The first
87  /// argument is a function pointer and the second is a context pointer that
88  /// gets passed into the DiagHandler.
89  ///
90  /// LLVMContext doesn't take ownership or interpret either of these
91  /// pointers.
92  void setInlineAsmDiagnosticHandler(InlineAsmDiagHandlerTy DiagHandler,
93                                     void *DiagContext = nullptr);
94
95  /// getInlineAsmDiagnosticHandler - Return the diagnostic handler set by
96  /// setInlineAsmDiagnosticHandler.
97  InlineAsmDiagHandlerTy getInlineAsmDiagnosticHandler() const;
98
99  /// getInlineAsmDiagnosticContext - Return the diagnostic context set by
100  /// setInlineAsmDiagnosticHandler.
101  void *getInlineAsmDiagnosticContext() const;
102
103  /// setDiagnosticHandler - This method sets a handler that is invoked
104  /// when the backend needs to report anything to the user.  The first
105  /// argument is a function pointer and the second is a context pointer that
106  /// gets passed into the DiagHandler.  The third argument should be set to
107  /// true if the handler only expects enabled diagnostics.
108  ///
109  /// LLVMContext doesn't take ownership or interpret either of these
110  /// pointers.
111  void setDiagnosticHandler(DiagnosticHandlerTy DiagHandler,
112                            void *DiagContext = nullptr,
113                            bool RespectFilters = false);
114
115  /// getDiagnosticHandler - Return the diagnostic handler set by
116  /// setDiagnosticHandler.
117  DiagnosticHandlerTy getDiagnosticHandler() const;
118
119  /// getDiagnosticContext - Return the diagnostic context set by
120  /// setDiagnosticContext.
121  void *getDiagnosticContext() const;
122
123  /// \brief Report a message to the currently installed diagnostic handler.
124  ///
125  /// This function returns, in particular in the case of error reporting
126  /// (DI.Severity == \a DS_Error), so the caller should leave the compilation
127  /// process in a self-consistent state, even though the generated code
128  /// need not be correct.
129  ///
130  /// The diagnostic message will be implicitly prefixed with a severity keyword
131  /// according to \p DI.getSeverity(), i.e., "error: " for \a DS_Error,
132  /// "warning: " for \a DS_Warning, and "note: " for \a DS_Note.
133  void diagnose(const DiagnosticInfo &DI);
134
135  /// \brief Registers a yield callback with the given context.
136  ///
137  /// The yield callback function may be called by LLVM to transfer control back
138  /// to the client that invoked the LLVM compilation. This can be used to yield
139  /// control of the thread, or perform periodic work needed by the client.
140  /// There is no guaranteed frequency at which callbacks must occur; in fact,
141  /// the client is not guaranteed to ever receive this callback. It is at the
142  /// sole discretion of LLVM to do so and only if it can guarantee that
143  /// suspending the thread won't block any forward progress in other LLVM
144  /// contexts in the same process.
145  ///
146  /// At a suspend point, the state of the current LLVM context is intentionally
147  /// undefined. No assumptions about it can or should be made. Only LLVM
148  /// context API calls that explicitly state that they can be used during a
149  /// yield callback are allowed to be used. Any other API calls into the
150  /// context are not supported until the yield callback function returns
151  /// control to LLVM. Other LLVM contexts are unaffected by this restriction.
152  void setYieldCallback(YieldCallbackTy Callback, void *OpaqueHandle);
153
154  /// \brief Calls the yield callback (if applicable).
155  ///
156  /// This transfers control of the current thread back to the client, which may
157  /// suspend the current thread. Only call this method when LLVM doesn't hold
158  /// any global mutex or cannot block the execution in another LLVM context.
159  void yield();
160
161  /// emitError - Emit an error message to the currently installed error handler
162  /// with optional location information.  This function returns, so code should
163  /// be prepared to drop the erroneous construct on the floor and "not crash".
164  /// The generated code need not be correct.  The error message will be
165  /// implicitly prefixed with "error: " and should not end with a ".".
166  void emitError(unsigned LocCookie, const Twine &ErrorStr);
167  void emitError(const Instruction *I, const Twine &ErrorStr);
168  void emitError(const Twine &ErrorStr);
169
170  /// \brief Query for a debug option's value.
171  ///
172  /// This function returns typed data populated from command line parsing.
173  template <typename ValT, typename Base, ValT(Base::*Mem)>
174  ValT getOption() const {
175    return OptionRegistry::instance().template get<ValT, Base, Mem>();
176  }
177
178private:
179  LLVMContext(LLVMContext&) = delete;
180  void operator=(LLVMContext&) = delete;
181
182  /// addModule - Register a module as being instantiated in this context.  If
183  /// the context is deleted, the module will be deleted as well.
184  void addModule(Module*);
185
186  /// removeModule - Unregister a module from this context.
187  void removeModule(Module*);
188
189  // Module needs access to the add/removeModule methods.
190  friend class Module;
191};
192
193/// getGlobalContext - Returns a global context.  This is for LLVM clients that
194/// only care about operating on a single thread.
195extern LLVMContext &getGlobalContext();
196
197// Create wrappers for C Binding types (see CBindingWrapping.h).
198DEFINE_SIMPLE_CONVERSION_FUNCTIONS(LLVMContext, LLVMContextRef)
199
200/* Specialized opaque context conversions.
201 */
202inline LLVMContext **unwrap(LLVMContextRef* Tys) {
203  return reinterpret_cast<LLVMContext**>(Tys);
204}
205
206inline LLVMContextRef *wrap(const LLVMContext **Tys) {
207  return reinterpret_cast<LLVMContextRef*>(const_cast<LLVMContext**>(Tys));
208}
209
210}
211
212#endif
213