Signals.h

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//===- llvm/Support/Signals.h - Signal Handling support ---------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines some helpful functions for dealing with the possibility of
// unix signals occurring while your program is running.
//
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_SUPPORT_SIGNALS_H
#define LLVM_SUPPORT_SIGNALS_H
 
#include "llvm/Config/llvm-config.h"
#include "llvm/Support/Compiler.h"
#include <cstdint>
#include <string>
 
#if LLVM_ENABLE_DEBUGLOC_TRACKING_ORIGIN
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/SmallVector.h"
namespace llvm {
// Typedefs that are convenient but only used by the stack-trace-collection code
// added if DebugLoc origin-tracking is enabled.
using AddressSet = DenseSet<void *>;
using SymbolizedAddressMap = DenseMap<void *, SmallVector<std::string, 0>>;
} // namespace llvm
#endif
 
namespace llvm {
class StringRef;
class raw_ostream;
 
namespace sys {
 
/// This function runs all the registered interrupt handlers, including the
/// removal of files registered by RemoveFileOnSignal.
LLVM_ABI void RunInterruptHandlers();
 
/// This function registers signal handlers to ensure that if a signal gets
/// delivered that the named file is removed.
/// Remove a file if a fatal signal occurs.
LLVM_ABI bool RemoveFileOnSignal(StringRef Filename,
                                 std::string *ErrMsg = nullptr);
 
/// This function removes a file from the list of files to be removed on
/// signal delivery.
LLVM_ABI void DontRemoveFileOnSignal(StringRef Filename);
 
/// When an error signal (such as SIGABRT or SIGSEGV) is delivered to the
/// process, print a stack trace and then exit.
/// Print a stack trace if a fatal signal occurs.
/// \param Argv0 the current binary name, used to find the symbolizer
///        relative to the current binary before searching $PATH; can be
///        StringRef(), in which case we will only search $PATH.
/// \param DisableCrashReporting if \c true, disable the normal crash
///        reporting mechanisms on the underlying operating system.
LLVM_ABI void PrintStackTraceOnErrorSignal(StringRef Argv0,
                                           bool DisableCrashReporting = false);
 
/// Disable all system dialog boxes that appear when the process crashes.
LLVM_ABI void DisableSystemDialogsOnCrash();
 
/// Print the stack trace using the given \c raw_ostream object.
/// \param Depth refers to the number of stackframes to print. If not
///        specified, the entire frame is printed.
LLVM_ABI void PrintStackTrace(raw_ostream &OS, int Depth = 0);
 
#if LLVM_ENABLE_DEBUGLOC_TRACKING_ORIGIN
#ifdef NDEBUG
#error DebugLoc origin-tracking should not be enabled in Release builds.
#endif
/// Populates the given array with a stack trace of the current program, up to
/// MaxDepth frames. Returns the number of frames returned, which will be
/// inserted into \p StackTrace from index 0. All entries after the returned
/// depth will be unmodified. NB: This is only intended to be used for
/// introspection of LLVM by Debugify, will not be enabled in release builds,
/// and should not be relied on for other purposes.
template <unsigned long MaxDepth>
int getStackTrace(std::array<void *, MaxDepth> &StackTrace);
 
/// Takes a set of \p Addresses, symbolizes them and stores the result in the
/// provided \p SymbolizedAddresses map.
/// NB: This is only intended to be used for introspection of LLVM by
/// Debugify, will not be enabled in release builds, and should not be relied
/// on for other purposes.
void symbolizeAddresses(AddressSet &Addresses,
                        SymbolizedAddressMap &SymbolizedAddresses);
#endif
 
// Run all registered signal handlers.
LLVM_ABI void RunSignalHandlers();
 
using SignalHandlerCallback = void (*)(void *);
 
/// Add a function to be called when an abort/kill signal is delivered to the
/// process. The handler can have a cookie passed to it to identify what
/// instance of the handler it is.
LLVM_ABI void AddSignalHandler(SignalHandlerCallback FnPtr, void *Cookie);
 
/// This function registers a function to be called when the user "interrupts"
/// the program (typically by pressing ctrl-c).  When the user interrupts the
/// program, the specified interrupt function is called instead of the program
/// being killed, and the interrupt function automatically disabled.
///
/// Note that interrupt functions are not allowed to call any non-reentrant
/// functions.  An null interrupt function pointer disables the current
/// installed function.  Note also that the handler may be executed on a
/// different thread on some platforms.
LLVM_ABI void SetInterruptFunction(void (*IF)());
 
/// Registers a function to be called when an "info" signal is delivered to
/// the process.
///
/// On POSIX systems, this will be SIGUSR1; on systems that have it, SIGINFO
/// will also be used (typically ctrl-t).
///
/// Note that signal handlers are not allowed to call any non-reentrant
/// functions.  An null function pointer disables the current installed
/// function.  Note also that the handler may be executed on a different
/// thread on some platforms.
LLVM_ABI void SetInfoSignalFunction(void (*Handler)());
 
/// Registers a function to be called in a "one-shot" manner when a pipe
/// signal is delivered to the process (i.e., on a failed write to a pipe).
/// After the pipe signal is handled once, the handler is unregistered.
///
/// The LLVM signal handling code will not install any handler for the pipe
/// signal unless one is provided with this API (see \ref
/// DefaultOneShotPipeSignalHandler). This handler must be provided before
/// any other LLVM signal handlers are installed: the \ref InitLLVM
/// constructor has a flag that can simplify this setup.
///
/// Note that the handler is not allowed to call any non-reentrant
/// functions.  A null handler pointer disables the current installed
/// function.  Note also that the handler may be executed on a
/// different thread on some platforms.
LLVM_ABI void SetOneShotPipeSignalFunction(void (*Handler)());
 
/// On Unix systems and Windows, this function exits with an "IO error" exit
/// code.
LLVM_ABI void DefaultOneShotPipeSignalHandler();
 
#ifdef _WIN32
/// Windows does not support signals and this handler must be called manually.
LLVM_ABI void CallOneShotPipeSignalHandler();
#endif
 
/// This function does the following:
/// - clean up any temporary files registered with RemoveFileOnSignal()
/// - dump the callstack from the exception context
/// - call any relevant interrupt/signal handlers
/// - create a core/mini dump of the exception context whenever possible
/// Context is a system-specific failure context: it is the signal type on
/// Unix; the ExceptionContext on Windows.
LLVM_ABI void CleanupOnSignal(uintptr_t Context);
 
LLVM_ABI void unregisterHandlers();
} // namespace sys
} // namespace llvm
 
#endif