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 <cstdint>
21#include <memory>
22#include <string>
23
24namespace llvm {
25
26class DiagnosticInfo;
27enum DiagnosticSeverity : char;
28class Function;
29class Instruction;
30class LLVMContextImpl;
31class Module;
32class OptPassGate;
33template <typename T> class SmallVectorImpl;
34template <typename T> class StringMapEntry;
35class SMDiagnostic;
36class StringRef;
37class Twine;
38class LLVMRemarkStreamer;
39class raw_ostream;
40
41namespace remarks {
42class RemarkStreamer;
43}
44
45namespace SyncScope {
46
47typedef uint8_t ID;
48
49/// Known synchronization scope IDs, which always have the same value. All
50/// synchronization scope IDs that LLVM has special knowledge of are listed
51/// here. Additionally, this scheme allows LLVM to efficiently check for
52/// specific synchronization scope ID without comparing strings.
53enum {
54 /// Synchronized with respect to signal handlers executing in the same thread.
55 SingleThread = 0,
56
57 /// Synchronized with respect to all concurrently executing threads.
58 System = 1
59};
60
61} // end namespace SyncScope
62
63/// This is an important class for using LLVM in a threaded context. It
64/// (opaquely) owns and manages the core "global" data of LLVM's core
65/// infrastructure, including the type and constant uniquing tables.
66/// LLVMContext itself provides no locking guarantees, so you should be careful
67/// to have one context per thread.
68class LLVMContext {
69public:
70 LLVMContextImpl *const pImpl;
71 LLVMContext();
72 LLVMContext(LLVMContext &) = delete;
73 LLVMContext &operator=(const LLVMContext &) = delete;
74 ~LLVMContext();
75
76 // Pinned metadata names, which always have the same value. This is a
77 // compile-time performance optimization, not a correctness optimization.
78 enum : unsigned {
79#define LLVM_FIXED_MD_KIND(EnumID, Name, Value) EnumID = Value,
80#include "llvm/IR/FixedMetadataKinds.def"
81#undef LLVM_FIXED_MD_KIND
82 };
83
84 /// Known operand bundle tag IDs, which always have the same value. All
85 /// operand bundle tags that LLVM has special knowledge of are listed here.
86 /// Additionally, this scheme allows LLVM to efficiently check for specific
87 /// operand bundle tags without comparing strings. Keep this in sync with
88 /// LLVMContext::LLVMContext().
89 enum : unsigned {
90 OB_deopt = 0, // "deopt"
91 OB_funclet = 1, // "funclet"
92 OB_gc_transition = 2, // "gc-transition"
93 OB_cfguardtarget = 3, // "cfguardtarget"
94 OB_preallocated = 4, // "preallocated"
95 OB_gc_live = 5, // "gc-live"
96 OB_clang_arc_attachedcall = 6, // "clang.arc.attachedcall"
97 };
98
99 /// getMDKindID - Return a unique non-zero ID for the specified metadata kind.
100 /// This ID is uniqued across modules in the current LLVMContext.
101 unsigned getMDKindID(StringRef Name) const;
102
103 /// getMDKindNames - Populate client supplied SmallVector with the name for
104 /// custom metadata IDs registered in this LLVMContext.
105 void getMDKindNames(SmallVectorImpl<StringRef> &Result) const;
106
107 /// getOperandBundleTags - Populate client supplied SmallVector with the
108 /// bundle tags registered in this LLVMContext. The bundle tags are ordered
109 /// by increasing bundle IDs.
110 /// \see LLVMContext::getOperandBundleTagID
111 void getOperandBundleTags(SmallVectorImpl<StringRef> &Result) const;
112
113 /// getOrInsertBundleTag - Returns the Tag to use for an operand bundle of
114 /// name TagName.
115 StringMapEntry<uint32_t> *getOrInsertBundleTag(StringRef TagName) const;
116
117 /// getOperandBundleTagID - Maps a bundle tag to an integer ID. Every bundle
118 /// tag registered with an LLVMContext has an unique ID.
119 uint32_t getOperandBundleTagID(StringRef Tag) const;
120
121 /// getOrInsertSyncScopeID - Maps synchronization scope name to
122 /// synchronization scope ID. Every synchronization scope registered with
123 /// LLVMContext has unique ID except pre-defined ones.
124 SyncScope::ID getOrInsertSyncScopeID(StringRef SSN);
125
126 /// getSyncScopeNames - Populates client supplied SmallVector with
127 /// synchronization scope names registered with LLVMContext. Synchronization
128 /// scope names are ordered by increasing synchronization scope IDs.
129 void getSyncScopeNames(SmallVectorImpl<StringRef> &SSNs) const;
130
131 /// Define the GC for a function
132 void setGC(const Function &Fn, std::string GCName);
133
134 /// Return the GC for a function
135 const std::string &getGC(const Function &Fn);
136
137 /// Remove the GC for a function
138 void deleteGC(const Function &Fn);
139
140 /// Return true if the Context runtime configuration is set to discard all
141 /// value names. When true, only GlobalValue names will be available in the
142 /// IR.
143 bool shouldDiscardValueNames() const;
144
145 /// Set the Context runtime configuration to discard all value name (but
146 /// GlobalValue). Clients can use this flag to save memory and runtime,
147 /// especially in release mode.
148 void setDiscardValueNames(bool Discard);
149
150 /// Whether there is a string map for uniquing debug info
151 /// identifiers across the context. Off by default.
152 bool isODRUniquingDebugTypes() const;
153 void enableDebugTypeODRUniquing();
154 void disableDebugTypeODRUniquing();
155
156 /// Defines the type of a yield callback.
157 /// \see LLVMContext::setYieldCallback.
158 using YieldCallbackTy = void (*)(LLVMContext *Context, void *OpaqueHandle);
159
160 /// setDiagnosticHandlerCallBack - This method sets a handler call back
161 /// that is invoked when the backend needs to report anything to the user.
162 /// The first argument is a function pointer and the second is a context pointer
163 /// that gets passed into the DiagHandler. The third argument should be set to
164 /// true if the handler only expects enabled diagnostics.
165 ///
166 /// LLVMContext doesn't take ownership or interpret either of these
167 /// pointers.
168 void setDiagnosticHandlerCallBack(
169 DiagnosticHandler::DiagnosticHandlerTy DiagHandler,
170 void *DiagContext = nullptr, bool RespectFilters = false);
171
172 /// setDiagnosticHandler - This method sets unique_ptr to object of
173 /// DiagnosticHandler to provide custom diagnostic handling. The first
174 /// argument is unique_ptr of object of type DiagnosticHandler or a derived
175 /// of that. The second argument should be set to true if the handler only
176 /// expects enabled diagnostics.
177 ///
178 /// Ownership of this pointer is moved to LLVMContextImpl.
179 void setDiagnosticHandler(std::unique_ptr<DiagnosticHandler> &&DH,
180 bool RespectFilters = false);
181
182 /// getDiagnosticHandlerCallBack - Return the diagnostic handler call back set by
183 /// setDiagnosticHandlerCallBack.
184 DiagnosticHandler::DiagnosticHandlerTy getDiagnosticHandlerCallBack() const;
185
186 /// getDiagnosticContext - Return the diagnostic context set by
187 /// setDiagnosticContext.
188 void *getDiagnosticContext() const;
189
190 /// getDiagHandlerPtr - Returns const raw pointer of DiagnosticHandler set by
191 /// setDiagnosticHandler.
192 const DiagnosticHandler *getDiagHandlerPtr() const;
193
194 /// getDiagnosticHandler - transfers ownership of DiagnosticHandler unique_ptr
195 /// to caller.
196 std::unique_ptr<DiagnosticHandler> getDiagnosticHandler();
197
198 /// Return if a code hotness metric should be included in optimization
199 /// diagnostics.
200 bool getDiagnosticsHotnessRequested() const;
201 /// Set if a code hotness metric should be included in optimization
202 /// diagnostics.
203 void setDiagnosticsHotnessRequested(bool Requested);
204
205 /// Return the minimum hotness value a diagnostic would need in order
206 /// to be included in optimization diagnostics.
207 ///
208 /// Three possible return values:
209 /// 0 - threshold is disabled. Everything will be printed out.
210 /// positive int - threshold is set.
211 /// UINT64_MAX - threshold is not yet set, and needs to be synced from
212 /// profile summary. Note that in case of missing profile
213 /// summary, threshold will be kept at "MAX", effectively
214 /// suppresses all remarks output.
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(Optional<uint64_t> Threshold);
220
221 /// Return if hotness threshold is requested from PSI.
222 bool isDiagnosticsHotnessThresholdSetFromPSI() const;
223
224 /// The "main remark streamer" used by all the specialized remark streamers.
225 /// This streamer keeps generic remark metadata in memory throughout the life
226 /// of the LLVMContext. This metadata may be emitted in a section in object
227 /// files depending on the format requirements.
228 ///
229 /// All specialized remark streamers should convert remarks to
230 /// llvm::remarks::Remark and emit them through this streamer.
231 remarks::RemarkStreamer *getMainRemarkStreamer();
232 const remarks::RemarkStreamer *getMainRemarkStreamer() const;
233 void setMainRemarkStreamer(
234 std::unique_ptr<remarks::RemarkStreamer> MainRemarkStreamer);
235
236 /// The "LLVM remark streamer" used by LLVM to serialize remark diagnostics
237 /// comming from IR and MIR passes.
238 ///
239 /// If it does not exist, diagnostics are not saved in a file but only emitted
240 /// via the diagnostic handler.
241 LLVMRemarkStreamer *getLLVMRemarkStreamer();
242 const LLVMRemarkStreamer *getLLVMRemarkStreamer() const;
243 void
244 setLLVMRemarkStreamer(std::unique_ptr<LLVMRemarkStreamer> RemarkStreamer);
245
246 /// Get the prefix that should be printed in front of a diagnostic of
247 /// the given \p Severity
248 static const char *getDiagnosticMessagePrefix(DiagnosticSeverity Severity);
249
250 /// Report a message to the currently installed diagnostic handler.
251 ///
252 /// This function returns, in particular in the case of error reporting
253 /// (DI.Severity == \a DS_Error), so the caller should leave the compilation
254 /// process in a self-consistent state, even though the generated code
255 /// need not be correct.
256 ///
257 /// The diagnostic message will be implicitly prefixed with a severity keyword
258 /// according to \p DI.getSeverity(), i.e., "error: " for \a DS_Error,
259 /// "warning: " for \a DS_Warning, and "note: " for \a DS_Note.
260 void diagnose(const DiagnosticInfo &DI);
261
262 /// Registers a yield callback with the given context.
263 ///
264 /// The yield callback function may be called by LLVM to transfer control back
265 /// to the client that invoked the LLVM compilation. This can be used to yield
266 /// control of the thread, or perform periodic work needed by the client.
267 /// There is no guaranteed frequency at which callbacks must occur; in fact,
268 /// the client is not guaranteed to ever receive this callback. It is at the
269 /// sole discretion of LLVM to do so and only if it can guarantee that
270 /// suspending the thread won't block any forward progress in other LLVM
271 /// contexts in the same process.
272 ///
273 /// At a suspend point, the state of the current LLVM context is intentionally
274 /// undefined. No assumptions about it can or should be made. Only LLVM
275 /// context API calls that explicitly state that they can be used during a
276 /// yield callback are allowed to be used. Any other API calls into the
277 /// context are not supported until the yield callback function returns
278 /// control to LLVM. Other LLVM contexts are unaffected by this restriction.
279 void setYieldCallback(YieldCallbackTy Callback, void *OpaqueHandle);
280
281 /// Calls the yield callback (if applicable).
282 ///
283 /// This transfers control of the current thread back to the client, which may
284 /// suspend the current thread. Only call this method when LLVM doesn't hold
285 /// any global mutex or cannot block the execution in another LLVM context.
286 void yield();
287
288 /// emitError - Emit an error message to the currently installed error handler
289 /// with optional location information. This function returns, so code should
290 /// be prepared to drop the erroneous construct on the floor and "not crash".
291 /// The generated code need not be correct. The error message will be
292 /// implicitly prefixed with "error: " and should not end with a ".".
293 void emitError(unsigned LocCookie, const Twine &ErrorStr);
294 void emitError(const Instruction *I, const Twine &ErrorStr);
295 void emitError(const Twine &ErrorStr);
296
297 /// Access the object which can disable optional passes and individual
298 /// optimizations at compile time.
299 OptPassGate &getOptPassGate() const;
300
301 /// Set the object which can disable optional passes and individual
302 /// optimizations at compile time.
303 ///
304 /// The lifetime of the object must be guaranteed to extend as long as the
305 /// LLVMContext is used by compilation.
306 void setOptPassGate(OptPassGate&);
307
308private:
309 // Module needs access to the add/removeModule methods.
310 friend class Module;
311
312 /// addModule - Register a module as being instantiated in this context. If
313 /// the context is deleted, the module will be deleted as well.
314 void addModule(Module*);
315
316 /// removeModule - Unregister a module from this context.
317 void removeModule(Module*);
318};
319
320// Create wrappers for C Binding types (see CBindingWrapping.h).
321DEFINE_SIMPLE_CONVERSION_FUNCTIONS(LLVMContext, LLVMContextRef)
322
323/* Specialized opaque context conversions.
324 */
325inline LLVMContext **unwrap(LLVMContextRef* Tys) {
326 return reinterpret_cast<LLVMContext**>(Tys);
327}
328
329inline LLVMContextRef *wrap(const LLVMContext **Tys) {
330 return reinterpret_cast<LLVMContextRef*>(const_cast<LLVMContext**>(Tys));
331}
332
333} // end namespace llvm
334
335#endif // LLVM_IR_LLVMCONTEXT_H
336