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Revert r282692: Use fallback_malloc to allocate __cxa_eh_globals in case of dynamic memory exhaustion. 

The test breaks build bots.

llvm-svn: 282703
This commit is contained in:
Igor Kudrin 2016-09-29 08:11:57 +00:00
parent fdaaca8ade
commit 49df799762
7 changed files with 44 additions and 130 deletions
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1
libcxxabi/src/CMakeLists.txt
View File

@ -12,7 +12,6 @@ set(LIBCXXABI_SOURCES
cxa_vector.cpp
cxa_virtual.cpp
exception.cpp
fallback_malloc.cpp
private_typeinfo.cpp
stdexcept.cpp
typeinfo.cpp

28
libcxxabi/src/cxa_exception.cpp
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@ -15,10 +15,13 @@
#include "cxxabi.h"
#include <exception> // for std::terminate
#include <cstdlib> // for malloc, free
#include <cstring> // for memset
#ifndef _LIBCXXABI_HAS_NO_THREADS
# include <pthread.h> // for fallback_malloc.ipp's mutexes
#endif
#include "cxa_exception.hpp"
#include "cxa_handlers.hpp"
#include "fallback_malloc.h"
// +---------------------------+-----------------------------+---------------+
// | __cxa_exception | _Unwind_Exception CLNGC++\0 | thrown object |
@ -101,6 +104,20 @@ static inline int decrementHandlerCount(__cxa_exception *exception) {
return --exception->handlerCount;
}
#include "fallback_malloc.ipp"
// Allocate some memory from _somewhere_
static void *do_malloc(size_t size) {
void *ptr = std::malloc(size);
if (NULL == ptr) // if malloc fails, fall back to emergency stash
ptr = fallback_malloc(size);
return ptr;
}
static void do_free(void *ptr) {
is_fallback_ptr(ptr) ? fallback_free(ptr) : std::free(ptr);
}
/*
If reason isn't _URC_FOREIGN_EXCEPTION_CAUGHT, then the terminateHandler
stored in exc is called. Otherwise the exceptionDestructor stored in
@ -141,8 +158,7 @@ extern "C" {
// user's exception object.
_LIBCXXABI_FUNC_VIS void *__cxa_allocate_exception(size_t thrown_size) throw() {
size_t actual_size = cxa_exception_size_from_exception_thrown_size(thrown_size);
__cxa_exception *exception_header =
static_cast<__cxa_exception *>(__malloc_with_fallback(actual_size));
__cxa_exception* exception_header = static_cast<__cxa_exception*>(do_malloc(actual_size));
if (NULL == exception_header)
std::terminate();
std::memset(exception_header, 0, actual_size);
@ -152,7 +168,7 @@ _LIBCXXABI_FUNC_VIS void *__cxa_allocate_exception(size_t thrown_size) throw() {
// Free a __cxa_exception object allocated with __cxa_allocate_exception.
_LIBCXXABI_FUNC_VIS void __cxa_free_exception(void *thrown_object) throw() {
__free_with_fallback(cxa_exception_from_thrown_object(thrown_object));
do_free(cxa_exception_from_thrown_object(thrown_object));
}
@ -161,7 +177,7 @@ _LIBCXXABI_FUNC_VIS void __cxa_free_exception(void *thrown_object) throw() {
// Otherwise, it will work like __cxa_allocate_exception.
void * __cxa_allocate_dependent_exception () {
size_t actual_size = sizeof(__cxa_dependent_exception);
void *ptr = __malloc_with_fallback(actual_size);
void *ptr = do_malloc(actual_size);
if (NULL == ptr)
std::terminate();
std::memset(ptr, 0, actual_size);
@ -172,7 +188,7 @@ void * __cxa_allocate_dependent_exception () {
// This function shall free a dependent_exception.
// It does not affect the reference count of the primary exception.
void __cxa_free_dependent_exception (void * dependent_exception) {
__free_with_fallback(dependent_exception);
do_free(dependent_exception);
}

6
libcxxabi/src/cxa_exception_storage.cpp
View File

@ -45,8 +45,8 @@ extern "C" {
#else
#include <pthread.h>
#include <cstdlib> // for calloc, free
#include "abort_message.h"
#include "fallback_malloc.h"
// In general, we treat all pthread errors as fatal.
// We cannot call std::terminate() because that will in turn
@ -58,7 +58,7 @@ namespace {
pthread_once_t flag_ = PTHREAD_ONCE_INIT;
void destruct_ (void *p) {
__free_with_fallback ( p );
std::free ( p );
if ( 0 != ::pthread_setspecific ( key_, NULL ) )
abort_message("cannot zero out thread value for __cxa_get_globals()");
}
@ -77,7 +77,7 @@ extern "C" {
// If this is the first time we've been asked for these globals, create them
if ( NULL == retVal ) {
retVal = static_cast<__cxa_eh_globals*>
(__calloc_with_fallback (1, sizeof (__cxa_eh_globals)));
(std::calloc (1, sizeof (__cxa_eh_globals)));
if ( NULL == retVal )
abort_message("cannot allocate __cxa_eh_globals");
if ( 0 != pthread_setspecific ( key_, retVal ) )

31
libcxxabi/src/fallback_malloc.h
View File

@ -1,31 +0,0 @@
//===------------------------- fallback_malloc.h --------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef _FALLBACK_MALLOC_H
#define _FALLBACK_MALLOC_H
#include <cstddef> // for size_t
namespace __cxxabiv1 {
#pragma GCC visibility push(hidden)
// Allocate some memory from _somewhere_
void * __malloc_with_fallback(size_t size);
// Allocate and zero-initialize memory from _somewhere_
void * __calloc_with_fallback(size_t count, size_t size);
void __free_with_fallback(void *ptr);
#pragma GCC visibility pop
} // namespace __cxxabiv1
#endif

74
libcxxabi/src/fallback_malloc.cpp → libcxxabi/src/fallback_malloc.ipp
View File

@ -1,24 +1,19 @@
//===------------------------ fallback_malloc.cpp -------------------------===//
//===------------------------ fallback_malloc.ipp -------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//
// This file implements the "Exception Handling APIs"
// http://mentorembedded.github.io/cxx-abi/abi-eh.html
//
//===----------------------------------------------------------------------===//
#include "fallback_malloc.h"
#include "config.h"
#include <cstdlib> // for malloc, calloc, free
#include <cstring> // for memset
#ifndef _LIBCXXABI_HAS_NO_THREADS
#include <pthread.h> // for mutexes
#endif
// A small, simple heap manager based (loosely) on
// A small, simple heap manager based (loosely) on
// the startup heap manager from FreeBSD, optimized for space.
//
// Manages a fixed-size memory pool, supports malloc and free only.
@ -54,9 +49,9 @@ private:
#endif
};
static const size_t HEAP_SIZE = 512;
char heap [ HEAP_SIZE ] __attribute__((aligned));
#define HEAP_SIZE 512
char heap [ HEAP_SIZE ];
typedef unsigned short heap_offset;
typedef unsigned short heap_size;
@ -74,13 +69,13 @@ heap_node *node_from_offset ( const heap_offset offset )
heap_offset offset_from_node ( const heap_node *ptr )
{ return static_cast<heap_offset>(static_cast<size_t>(reinterpret_cast<const char *>(ptr) - heap) / sizeof (heap_node)); }
void init_heap () {
freelist = (heap_node *) heap;
freelist->next_node = offset_from_node ( list_end );
freelist->len = HEAP_SIZE / sizeof (heap_node);
}
// How big a chunk we allocate
size_t alloc_size (size_t len)
{ return (len + sizeof(heap_node) - 1) / sizeof(heap_node) + 1; }
@ -92,12 +87,12 @@ void *fallback_malloc(size_t len) {
heap_node *p, *prev;
const size_t nelems = alloc_size ( len );
mutexor mtx ( &heap_mutex );
if ( NULL == freelist )
init_heap ();
// Walk the free list, looking for a "big enough" chunk
for (p = freelist, prev = 0;
for (p = freelist, prev = 0;
p && p != list_end; prev = p, p = node_from_offset ( p->next_node)) {
if (p->len > nelems) { // chunk is larger, shorten, and return the tail
@ -109,7 +104,7 @@ void *fallback_malloc(size_t len) {
q->len = static_cast<heap_size>(nelems);
return (void *) (q + 1);
}
if (p->len == nelems) { // exact size match
if (prev == 0)
freelist = node_from_offset(p->next_node);
@ -135,7 +130,7 @@ void fallback_free (void *ptr) {
std::cout << "Freeing item at " << offset_from_node ( cp ) << " of size " << cp->len << std::endl;
#endif
for (p = freelist, prev = 0;
for (p = freelist, prev = 0;
p && p != list_end; prev = p, p = node_from_offset (p->next_node)) {
#ifdef DEBUG_FALLBACK_MALLOC
std::cout << " p, cp, after (p), after(cp) "
@ -179,10 +174,10 @@ size_t print_free_list () {
heap_size total_free = 0;
if ( NULL == freelist )
init_heap ();
for (p = freelist, prev = 0;
for (p = freelist, prev = 0;
p && p != list_end; prev = p, p = node_from_offset (p->next_node)) {
std::cout << ( prev == 0 ? "" : " ") << "Offset: " << offset_from_node ( p )
std::cout << ( prev == 0 ? "" : " ") << "Offset: " << offset_from_node ( p )
<< "\tsize: " << p->len << " Next: " << p->next_node << std::endl;
total_free += p->len;
}
@ -191,36 +186,3 @@ size_t print_free_list () {
}
#endif
} // end unnamed namespace
namespace __cxxabiv1 {
#pragma GCC visibility push(hidden)
void * __malloc_with_fallback(size_t size) {
void *ptr = std::malloc(size);
if (NULL == ptr) // if malloc fails, fall back to emergency stash
ptr = fallback_malloc(size);
return ptr;
}
void * __calloc_with_fallback(size_t count, size_t size) {
void *ptr = std::calloc(count, size);
if (NULL != ptr)
return ptr;
// if calloc fails, fall back to emergency stash
ptr = fallback_malloc(size * count);
if (NULL != ptr)
std::memset(ptr, 0, size * count);
return ptr;
}
void __free_with_fallback(void *ptr) {
if (is_fallback_ptr(ptr))
fallback_free(ptr);
else
std::free(ptr);
}
#pragma GCC visibility pop
} // namespace __cxxabiv1

32
libcxxabi/test/test_exception_storage_nodynmem.pass.cpp
View File

@ -1,32 +0,0 @@
//===--------------- test_exception_storage_nodynmem.cpp ------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include <assert.h>
#include <cstdlib>
static bool OverwrittenCallocCalled = false;
// Override calloc to simulate exhaustion of dynamic memory
void *calloc(size_t, size_t) {
OverwrittenCallocCalled = true;
return 0;
}
int main(int argc, char *argv[]) {
// Run the test a couple of times
// to ensure that fallback memory doesn't leak.
for (int I = 0; I < 1000; ++I)
try {
throw 42;
} catch (...) {
}
assert(OverwrittenCallocCalled);
return 0;
}

2
libcxxabi/test/test_fallback_malloc.pass.cpp
View File

@ -16,7 +16,7 @@ typedef std::deque<void *> container;
// #define DEBUG_FALLBACK_MALLOC
#define INSTRUMENT_FALLBACK_MALLOC
#include "../src/fallback_malloc.cpp"
#include "../src/fallback_malloc.ipp"
container alloc_series ( size_t sz ) {
container ptrs;