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Diffstat (limited to 'gcc/ada/seh_init.cc')
| -rw-r--r-- | gcc/ada/seh_init.cc | 308 |
1 files changed, 308 insertions, 0 deletions
diff --git a/gcc/ada/seh_init.cc b/gcc/ada/seh_init.cc new file mode 100644 index 0000000..16a1f69 --- /dev/null +++ b/gcc/ada/seh_init.cc @@ -0,0 +1,308 @@ +/**************************************************************************** + * * + * GNAT COMPILER COMPONENTS * + * * + * S E H - I N I T * + * * + * C Implementation File * + * * + * Copyright (C) 2005-2022, Free Software Foundation, Inc. * + * * + * GNAT is free software; you can redistribute it and/or modify it under * + * terms of the GNU General Public License as published by the Free Soft- * + * ware Foundation; either version 3, or (at your option) any later ver- * + * sion. GNAT is distributed in the hope that it will be useful, but WITH- * + * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY * + * or FITNESS FOR A PARTICULAR PURPOSE. * + * * + * As a special exception under Section 7 of GPL version 3, you are granted * + * additional permissions described in the GCC Runtime Library Exception, * + * version 3.1, as published by the Free Software Foundation. * + * * + * You should have received a copy of the GNU General Public License and * + * a copy of the GCC Runtime Library Exception along with this program; * + * see the files COPYING3 and COPYING.RUNTIME respectively. If not, see * + * <http://www.gnu.org/licenses/>. * + * * + * GNAT was originally developed by the GNAT team at New York University. * + * Extensive contributions were provided by Ada Core Technologies Inc. * + * * + ****************************************************************************/ + +/* This unit contains support for SEH (Structured Exception Handling). + Right now the only implementation is for Win32 and Cygwin. */ + +#if defined (_WIN32) || (defined (__CYGWIN__) && defined (__SEH__)) +/* Include system headers, before system.h poisons malloc. */ +#include <windows.h> +#include <excpt.h> +#endif + +#ifdef IN_RTS + +#include "runtime.h" + +/* We don't have libiberty, so use malloc. */ +#define xmalloc(S) malloc (S) + +#else +#include "config.h" +#include "system.h" +#endif + +#include "raise.h" + +#ifdef __cplusplus +extern "C" { +#endif + +/* Addresses of exception data blocks for predefined exceptions. */ +extern struct Exception_Data constraint_error; +extern struct Exception_Data numeric_error; +extern struct Exception_Data program_error; +extern struct Exception_Data storage_error; +extern struct Exception_Data tasking_error; +extern struct Exception_Data _abort_signal; + +#define Raise_From_Signal_Handler __gnat_raise_from_signal_handler +extern void Raise_From_Signal_Handler (struct Exception_Data *, const void *) + ATTRIBUTE_NORETURN; + + +#if defined (_WIN32) || (defined (__CYGWIN__) && defined (__SEH__)) + +/* Prototypes. */ +extern void _global_unwind2 (void *); + +EXCEPTION_DISPOSITION __gnat_SEH_error_handler +(struct _EXCEPTION_RECORD*, void*, struct _CONTEXT*, void*) ATTRIBUTE_NORETURN; + +struct Exception_Data * +__gnat_map_SEH (EXCEPTION_RECORD* ExceptionRecord, const char **msg); + +/* Convert an SEH exception to an Ada one. Return the exception ID and set + MSG to the corresponding message. */ + +struct Exception_Data * +__gnat_map_SEH (EXCEPTION_RECORD* ExceptionRecord, const char **msg) +{ + switch (ExceptionRecord->ExceptionCode) + { + case EXCEPTION_ACCESS_VIOLATION: + /* If the failing address isn't maximally aligned or if the page before + the faulting page is not accessible, this is a program error. */ + if ((ExceptionRecord->ExceptionInformation[1] & 3) != 0 + || IsBadCodePtr + ((FARPROC)(ExceptionRecord->ExceptionInformation[1] + 4096))) + { + *msg = "EXCEPTION_ACCESS_VIOLATION"; + return &program_error; + } + else + { + /* Otherwise this is a stack overflow. */ + *msg = "stack overflow or erroneous memory access"; + return &storage_error; + } + + case EXCEPTION_ARRAY_BOUNDS_EXCEEDED: + *msg = "EXCEPTION_ARRAY_BOUNDS_EXCEEDED"; + return &constraint_error; + + case EXCEPTION_DATATYPE_MISALIGNMENT: + *msg = "EXCEPTION_DATATYPE_MISALIGNMENT"; + return &constraint_error; + + case EXCEPTION_FLT_DENORMAL_OPERAND: + *msg = "EXCEPTION_FLT_DENORMAL_OPERAND"; + return &constraint_error; + + case EXCEPTION_FLT_DIVIDE_BY_ZERO: + *msg = "EXCEPTION_FLT_DENORMAL_OPERAND"; + return &constraint_error; + + case EXCEPTION_FLT_INVALID_OPERATION: + *msg = "EXCEPTION_FLT_INVALID_OPERATION"; + return &constraint_error; + + case EXCEPTION_FLT_OVERFLOW: + *msg = "EXCEPTION_FLT_OVERFLOW"; + return &constraint_error; + + case EXCEPTION_FLT_STACK_CHECK: + *msg = "EXCEPTION_FLT_STACK_CHECK"; + return &program_error; + + case EXCEPTION_FLT_UNDERFLOW: + *msg = "EXCEPTION_FLT_UNDERFLOW"; + return &constraint_error; + + case EXCEPTION_INT_DIVIDE_BY_ZERO: + *msg = "EXCEPTION_INT_DIVIDE_BY_ZERO"; + return &constraint_error; + + case EXCEPTION_INT_OVERFLOW: + *msg = "EXCEPTION_INT_OVERFLOW"; + return &constraint_error; + + case EXCEPTION_INVALID_DISPOSITION: + *msg = "EXCEPTION_INVALID_DISPOSITION"; + return &program_error; + + case EXCEPTION_NONCONTINUABLE_EXCEPTION: + *msg = "EXCEPTION_NONCONTINUABLE_EXCEPTION"; + return &program_error; + + case EXCEPTION_PRIV_INSTRUCTION: + *msg = "EXCEPTION_PRIV_INSTRUCTION"; + return &program_error; + + case EXCEPTION_SINGLE_STEP: + *msg = "EXCEPTION_SINGLE_STEP"; + return &program_error; + + case EXCEPTION_STACK_OVERFLOW: + *msg = "EXCEPTION_STACK_OVERFLOW"; + return &storage_error; + + default: + *msg = NULL; + return NULL; + } +} + +#if !(defined (_WIN64) && defined (__SEH__)) + +/* The "fake" exception handler to be associated with the .text section. */ + +EXCEPTION_DISPOSITION +__gnat_SEH_error_handler (struct _EXCEPTION_RECORD* ExceptionRecord, + void *EstablisherFrame ATTRIBUTE_UNUSED, + struct _CONTEXT* ContextRecord ATTRIBUTE_UNUSED, + void *DispatcherContext ATTRIBUTE_UNUSED) +{ + struct Exception_Data *exception; + const char *msg; + + exception = __gnat_map_SEH (ExceptionRecord, &msg); + + if (exception == NULL) + { + exception = &program_error; + msg = "unhandled signal"; + } + +#if !defined (_WIN64) + /* This call is important as it avoids locking the second time we catch a + signal; it's equivalent to RtlUnwind (EstablisherFrame, NULL, NULL, 0); + Note that this routine is documented as internal to Windows and should + not be used. */ + _global_unwind2 (EstablisherFrame); +#endif + + Raise_From_Signal_Handler (exception, msg); +} + +#endif /* !(defined (_WIN64) && defined (__SEH__)) */ + +#if defined (_WIN64) + +/* On x86-64/Windows the EH mechanism is no more based on a chained list of + handlers addresses on the stack. Instead unwinding information is used + to retrieve the exception handler (similar to DWARF2 unwinding). So in + order to register an exception handler, we need to put in the binary + some unwinding information. This information can be present statically + in the image file inside the .pdata section or registered through the + RtlAddFunctionTable API. In the case where the GCC toolchain does not + generate the .pdata information for each function, we don't really need + to handle SEH exceptions except for signal handling, so we register a + "fake" unwinding data that associates a SEH exception handler with the + complete .text section. As we never return from the handler, the system + does not try to do the final unwinding using the .pdata information and + the unwinding is handled by the runtime using the GNAT or GCC mechanism. + + Solutions based on SetUnhandledExceptionFilter have been discarded as this + function is mostly disabled on latest Windows versions. + + Using AddVectoredExceptionHandler should also be discarded as it overrides + all SEH exception handlers that might be present in the program itself and + the loaded DLL; for example it results in unexpected behavior in the Win32 + subsystem. */ + +#ifndef __SEH__ + + /* Do not use this trick when GCC generates the .pdata information, since it + is not necessary and will conflict with the per-function data. */ +asm +( + " .section .rdata, \"dr\"\n" + " .align 4\n" + "unwind_info:\n" + " .byte 9\n" /* UNW_FLAG_EHANDLER | UNW_VERSION */ + " .byte 0\n" /* Prologue size. */ + " .byte 0\n" /* Count of unwind code. */ + " .byte 0\n" /* Frame register and offset. */ + " .rva __gnat_SEH_error_handler\n" + "\n" + " .section .pdata, \"dr\"\n" + " .align 4\n" + " .long 0\n" /* ImageBase */ + " .rva etext\n" + " .rva unwind_info\n" + "\n" + " .text\n" +); + +#endif /* __SEH__ */ + +/* Nothing to do, the handler is either not used or statically installed by + the asm statement just above. */ +void __gnat_install_SEH_handler (void *eh ATTRIBUTE_UNUSED) +{ +} + +#else /* defined (_WIN64) */ + +/* Install the Win32 SEH exception handler. Note that the caller must have + allocated 8 bytes on the stack and pass the pointer to this stack space. + This is needed as the SEH exception handler must be on the stack of the + thread. + + int buf[2]; + + __gnat_install_SEH_handler ((void*)buf); + + main(); + + This call must be done before calling the main procedure or the thread + entry. The stack space must exist during the entire main run. */ + +void +__gnat_install_SEH_handler (void *ER) +{ + int *ptr; + + /* Put current handler in PTR. */ + asm ("mov %%fs:(0),%0" : "=r" (ptr)); + + ((int *)ER)[0] = (int)ptr; /* previous handler */ + ((int *)ER)[1] = (int)__gnat_SEH_error_handler; /* new handler */ + + /* ER is the new handler, set fs:(0) to this value. */ + asm volatile ("mov %0,%%fs:(0)": : "r" (ER)); +} + +#endif + +#else /* defined (_WIN32) */ + +/* For all non-Windows targets we provide a dummy SEH install handler. */ +void __gnat_install_SEH_handler (void *eh ATTRIBUTE_UNUSED) +{ +} + +#endif + +#ifdef __cplusplus +} +#endif |