Recommit r282692: [libc++abi] Use fallback_malloc to allocate __cxa_eh_globals in case of dynamic memory exhaustion.
Throwing an exception for the first time may lead to call calloc to
allocate memory for __cxa_eh_globals. If the memory pool is exhausted
at that moment, it results in abnormal termination of the program.
This patch addresses the issue by using fallback_malloc in that case.
In this revision, some restrictions were added into the test to not
run it in unsuitable environments.
Differential Revision: https://reviews.llvm.org/D17815
llvm-svn: 283531
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: d9edde4ae2cd3e5350c3a981f6715de9f2457196
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index d951292..7cbfdf5 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -12,6 +12,7 @@
cxa_vector.cpp
cxa_virtual.cpp
exception.cpp
+ fallback_malloc.cpp
private_typeinfo.cpp
stdexcept.cpp
typeinfo.cpp
diff --git a/src/cxa_exception.cpp b/src/cxa_exception.cpp
index 603f869..757b3d4 100644
--- a/src/cxa_exception.cpp
+++ b/src/cxa_exception.cpp
@@ -15,13 +15,10 @@
#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 |
@@ -104,20 +101,6 @@
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
@@ -158,7 +141,8 @@
// 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*>(do_malloc(actual_size));
+ __cxa_exception *exception_header =
+ static_cast<__cxa_exception *>(__malloc_with_fallback(actual_size));
if (NULL == exception_header)
std::terminate();
std::memset(exception_header, 0, actual_size);
@@ -168,7 +152,7 @@
// Free a __cxa_exception object allocated with __cxa_allocate_exception.
_LIBCXXABI_FUNC_VIS void __cxa_free_exception(void *thrown_object) throw() {
- do_free(cxa_exception_from_thrown_object(thrown_object));
+ __free_with_fallback(cxa_exception_from_thrown_object(thrown_object));
}
@@ -177,7 +161,7 @@
// Otherwise, it will work like __cxa_allocate_exception.
void * __cxa_allocate_dependent_exception () {
size_t actual_size = sizeof(__cxa_dependent_exception);
- void *ptr = do_malloc(actual_size);
+ void *ptr = __malloc_with_fallback(actual_size);
if (NULL == ptr)
std::terminate();
std::memset(ptr, 0, actual_size);
@@ -188,7 +172,7 @@
// 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) {
- do_free(dependent_exception);
+ __free_with_fallback(dependent_exception);
}
diff --git a/src/cxa_exception_storage.cpp b/src/cxa_exception_storage.cpp
index 235b0cf..ec69094 100644
--- a/src/cxa_exception_storage.cpp
+++ b/src/cxa_exception_storage.cpp
@@ -45,8 +45,8 @@
#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 @@
pthread_once_t flag_ = PTHREAD_ONCE_INIT;
void destruct_ (void *p) {
- std::free ( p );
+ __free_with_fallback ( p );
if ( 0 != ::pthread_setspecific ( key_, NULL ) )
abort_message("cannot zero out thread value for __cxa_get_globals()");
}
@@ -77,7 +77,7 @@
// If this is the first time we've been asked for these globals, create them
if ( NULL == retVal ) {
retVal = static_cast<__cxa_eh_globals*>
- (std::calloc (1, sizeof (__cxa_eh_globals)));
+ (__calloc_with_fallback (1, sizeof (__cxa_eh_globals)));
if ( NULL == retVal )
abort_message("cannot allocate __cxa_eh_globals");
if ( 0 != pthread_setspecific ( key_, retVal ) )
diff --git a/src/fallback_malloc.ipp b/src/fallback_malloc.cpp
similarity index 81%
rename from src/fallback_malloc.ipp
rename to src/fallback_malloc.cpp
index 1d8f8a3..a436ed0 100644
--- a/src/fallback_malloc.ipp
+++ b/src/fallback_malloc.cpp
@@ -1,19 +1,24 @@
-//===------------------------ fallback_malloc.ipp -------------------------===//
+//===------------------------ fallback_malloc.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.
//
-//
-// This file implements the "Exception Handling APIs"
-// http://mentorembedded.github.io/cxx-abi/abi-eh.html
-//
//===----------------------------------------------------------------------===//
+#include "fallback_malloc.h"
+
#include "config.h"
-// A small, simple heap manager based (loosely) on
+#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
// the startup heap manager from FreeBSD, optimized for space.
//
// Manages a fixed-size memory pool, supports malloc and free only.
@@ -49,9 +54,9 @@
#endif
};
-
-#define HEAP_SIZE 512
-char heap [ HEAP_SIZE ];
+
+static const size_t HEAP_SIZE = 512;
+char heap [ HEAP_SIZE ] __attribute__((aligned));
typedef unsigned short heap_offset;
typedef unsigned short heap_size;
@@ -69,13 +74,13 @@
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; }
@@ -87,12 +92,12 @@
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
@@ -104,7 +109,7 @@
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);
@@ -130,7 +135,7 @@
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) "
@@ -174,10 +179,10 @@
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;
}
@@ -186,3 +191,36 @@
}
#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
diff --git a/src/fallback_malloc.h b/src/fallback_malloc.h
new file mode 100644
index 0000000..1078442
--- /dev/null
+++ b/src/fallback_malloc.h
@@ -0,0 +1,31 @@
+//===------------------------- 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