Introduce new error handling API.

This will replace exit()/abort() style error handling with an API
that allows clients to register custom error handling hooks.
The default is to call exit(1) when no error handler is provided.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74922 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Support/Compiler.h

@@ -56,4 +56,10 @@
 #define DISABLE_INLINE
 #endif
 
+#ifdef __GNUC__
+#define NORETURN __attribute__((noreturn))
+#else
+#define NORETURN
+#endif
+
 #endif

include/llvm/Support/ErrorHandling.h

@@ -0,0 +1,52 @@
+//===- llvm/Support/ErrorHandling.h - Callbacks for errors ------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines an API used to indicate error conditions.
+// Callbacks can be registered for these errors through this API.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_ERRORHANDLING_H
+#define LLVM_SUPPORT_ERRORHANDLING_H
+
+#include "llvm/Support/Compiler.h"
+
+namespace llvm {
+  // An error handler callback.
+  typedef void (*llvm_error_handler_t)(const std::string& reason);
+
+  // Installs a new error handler: this function will be called whenever a
+  // serious error is encountered by LLVM.
+  // If you are using llvm_start_multithreaded, you should register the handler
+  // before doing that.
+  //
+  // If no error handler is installed the default is to print the error message
+  // to stderr, and call exit(1).
+  // If an error handler is installed then it is the handler's responsibility to
+  // log the message, it will no longer be printed to stderr.
+  // If the error handler returns, then exit(1) will be called.
+  void llvm_install_error_handler(llvm_error_handler_t handler);
+
+  // Restores default error handling behaviour.
+  // This must not be called between llvm_start_multithreaded() and
+  // llvm_stop_multithreaded().
+  void llvm_remove_error_handler(void);
+
+  // Reports a serious error, calling any installed error handler.
+  // If no error handler is installed the default is to print the message to
+  void llvm_report_error(const std::string &reason) NORETURN;
+
+  // This function calls abort().
+  // Call this after assert(0), so that compiler knows the path is not
+  // reachable.
+  void llvm_unreachable(void) NORETURN;
+}
+
+#endif
+

lib/ExecutionEngine/ExecutionEngine.cpp

@@ -22,6 +22,7 @@
 #include "llvm/ExecutionEngine/ExecutionEngine.h"
 #include "llvm/ExecutionEngine/GenericValue.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MutexGuard.h"
 #include "llvm/System/DynamicLibrary.h"
 #include "llvm/System/Host.h"
@@ -640,7 +641,7 @@ GenericValue ExecutionEngine::getConstantValue(const Constant *C) {
       case Type::FP128TyID: {
         APFloat apfLHS = APFloat(LHS.IntVal);
         switch (CE->getOpcode()) {
-          default: assert(0 && "Invalid long double opcode"); abort();
+          default: assert(0 && "Invalid long double opcode");llvm_unreachable();
           case Instruction::FAdd:
             apfLHS.add(APFloat(RHS.IntVal), APFloat::rmNearestTiesToEven);
             GV.IntVal = apfLHS.bitcastToAPInt();
@@ -953,9 +954,8 @@ void ExecutionEngine::emitGlobals() {
             sys::DynamicLibrary::SearchForAddressOfSymbol(I->getName().c_str()))
           addGlobalMapping(I, SymAddr);
         else {
-          cerr << "Could not resolve external global address: "
-               << I->getName() << "\n";
-          abort();
+          llvm_report_error("Could not resolve external global address: "
+                            +I->getName());
         }
       }
     }

lib/ExecutionEngine/JIT/JIT.cpp

@@ -27,6 +27,7 @@
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetJITInfo.h"
 #include "llvm/Support/Dwarf.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MutexGuard.h"
 #include "llvm/System/DynamicLibrary.h"
 #include "llvm/Config/config.h"
@@ -671,9 +672,8 @@ void *JIT::getOrEmitGlobalVariable(const GlobalVariable *GV) {
 #endif
     Ptr = sys::DynamicLibrary::SearchForAddressOfSymbol(GV->getName().c_str());
     if (Ptr == 0 && !areDlsymStubsEnabled()) {
-      cerr << "Could not resolve external global address: "
-           << GV->getName() << "\n";
-      abort();
+      llvm_report_error("Could not resolve external global address: "
+                        +GV->getName());
     }
     addGlobalMapping(GV, Ptr);
   } else {

lib/Support/ErrorHandling.cpp

@@ -0,0 +1,53 @@
+//===- lib/Support/ErrorHandling.cpp - Callbacks for errors -----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines an API for error handling, it supersedes cerr+abort(), and 
+// cerr+exit() style error handling.
+// Callbacks can be registered for these errors through this API.
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/System/Threading.h"
+#include <cassert>
+#include <cstdlib>
+
+using namespace llvm;
+using namespace std;
+
+static llvm_error_handler_t ErrorHandler = 0;
+namespace llvm {
+void llvm_install_error_handler(llvm_error_handler_t handler) {
+  assert(!llvm_is_multithreaded() &&
+         "Cannot register error handlers after starting multithreaded mode!\n");
+  assert(!ErrorHandler && "Error handler already registered!\n");
+  ErrorHandler = handler;
+}
+
+void llvm_remove_error_handler(void) {
+  ErrorHandler = 0;
+}
+
+void llvm_report_error(const std::string &reason)
+{
+  if (!ErrorHandler) {
+    errs() << "LLVM ERROR: " << reason << "\n";
+  } else {
+    ErrorHandler(reason);
+  }
+  exit(1);
+}
+
+void llvm_unreachable(void)
+{
+  abort();
+}
+}
+