[PATCH] [ASan] Speed up stack trace unwinding for stacks of size 2.
Alexey Samsonov
samsonov at google.com
Tue Mar 4 05:03:46 PST 2014
Hi eugenis, ygribov,
We don't need to do any work in this case - just take
the current PC and caller PC.
http://llvm-reviews.chandlerc.com/D2936
Files:
lib/asan/asan_linux.cc
lib/asan/asan_stack.h
lib/asan/asan_allocator2.cc
lib/asan/asan_thread.h
test/asan/TestCases/malloc_context_size.cc
Index: lib/asan/asan_linux.cc
===================================================================
--- lib/asan/asan_linux.cc
+++ lib/asan/asan_linux.cc
@@ -18,6 +18,7 @@
#include "asan_interceptors.h"
#include "asan_internal.h"
#include "asan_thread.h"
+#include "sanitizer_common/sanitizer_flags.h"
#include "sanitizer_common/sanitizer_libc.h"
#include "sanitizer_common/sanitizer_procmaps.h"
Index: lib/asan/asan_stack.h
===================================================================
--- lib/asan/asan_stack.h
+++ lib/asan/asan_stack.h
@@ -19,48 +19,64 @@
#include "sanitizer_common/sanitizer_flags.h"
#include "sanitizer_common/sanitizer_stacktrace.h"
+namespace __asan {
+
// Get the stack trace with the given pc and bp.
// The pc will be in the position 0 of the resulting stack trace.
// The bp may refer to the current frame or to the caller's frame.
+ALWAYS_INLINE
+void GetStackTraceWithPcBpAndContext(StackTrace *stack, uptr max_depth, uptr pc,
+ uptr bp, void *context, bool fast) {
#if SANITIZER_WINDOWS
-#define GET_STACK_TRACE_WITH_PC_BP_AND_CONTEXT(max_s, pc, bp, context, fast) \
- StackTrace stack; \
- stack.Unwind(max_s, pc, bp, context, 0, 0, fast)
+ stack->Unwind(max_depth, pc, bp, context, 0, 0, fast);
#else
-#define GET_STACK_TRACE_WITH_PC_BP_AND_CONTEXT(max_s, pc, bp, context, fast) \
- StackTrace stack; \
- { \
- AsanThread *t; \
- stack.size = 0; \
- if (asan_inited) { \
- if ((t = GetCurrentThread()) && !t->isUnwinding()) { \
- uptr stack_top = t->stack_top(); \
- uptr stack_bottom = t->stack_bottom(); \
- ScopedUnwinding unwind_scope(t); \
- stack.Unwind(max_s, pc, bp, context, stack_top, stack_bottom, fast); \
- } else if (t == 0 && !fast) { \
- /* If GetCurrentThread() has failed, try to do slow unwind anyways. */ \
- stack.Unwind(max_s, pc, bp, context, 0, 0, false); \
- } \
- } \
+ AsanThread *t;
+ stack->size = 0;
+ if (asan_inited) {
+ if ((t = GetCurrentThread()) && !t->isUnwinding()) {
+ uptr stack_top = t->stack_top();
+ uptr stack_bottom = t->stack_bottom();
+ ScopedUnwinding unwind_scope(t);
+ stack->Unwind(max_depth, pc, bp, context, stack_top, stack_bottom, fast);
+ } else if (t == 0 && !fast) {
+ /* If GetCurrentThread() has failed, try to do slow unwind anyways. */
+ stack->Unwind(max_depth, pc, bp, context, 0, 0, false);
+ }
}
#endif // SANITIZER_WINDOWS
+}
+
+} // namespace __asan
// NOTE: A Rule of thumb is to retrieve stack trace in the interceptors
// as early as possible (in functions exposed to the user), as we generally
// don't want stack trace to contain functions from ASan internals.
#define GET_STACK_TRACE(max_size, fast) \
- GET_STACK_TRACE_WITH_PC_BP_AND_CONTEXT(max_size, StackTrace::GetCurrentPc(), \
- GET_CURRENT_FRAME(), 0, fast)
+ StackTrace stack; \
+ if (max_size <= 2) { \
+ stack.size = max_size; \
+ if (max_size > 0) { \
+ stack.top_frame_bp = GET_CURRENT_FRAME(); \
+ stack.trace[0] = StackTrace::GetCurrentPc(); \
+ } \
+ if (max_size > 1) \
+ stack.trace[1] = GET_CALLER_PC(); \
+ } else { \
+ GetStackTraceWithPcBpAndContext(&stack, max_size, \
+ StackTrace::GetCurrentPc(), \
+ GET_CURRENT_FRAME(), 0, fast); \
+ }
-#define GET_STACK_TRACE_FATAL(pc, bp) \
- GET_STACK_TRACE_WITH_PC_BP_AND_CONTEXT(kStackTraceMax, pc, bp, 0, \
- common_flags()->fast_unwind_on_fatal)
-
-#define GET_STACK_TRACE_SIGNAL(pc, bp, context) \
- GET_STACK_TRACE_WITH_PC_BP_AND_CONTEXT(kStackTraceMax, pc, bp, context, \
- common_flags()->fast_unwind_on_fatal)
+#define GET_STACK_TRACE_FATAL(pc, bp) \
+ StackTrace stack; \
+ GetStackTraceWithPcBpAndContext(&stack, kStackTraceMax, pc, bp, 0, \
+ common_flags()->fast_unwind_on_fatal)
+
+#define GET_STACK_TRACE_SIGNAL(pc, bp, context) \
+ StackTrace stack; \
+ GetStackTraceWithPcBpAndContext(&stack, kStackTraceMax, pc, bp, context, \
+ common_flags()->fast_unwind_on_fatal)
#define GET_STACK_TRACE_FATAL_HERE \
GET_STACK_TRACE(kStackTraceMax, common_flags()->fast_unwind_on_fatal)
Index: lib/asan/asan_allocator2.cc
===================================================================
--- lib/asan/asan_allocator2.cc
+++ lib/asan/asan_allocator2.cc
@@ -19,6 +19,7 @@
#include "asan_mapping.h"
#include "asan_poisoning.h"
#include "asan_report.h"
+#include "asan_stack.h"
#include "asan_thread.h"
#include "sanitizer_common/sanitizer_allocator.h"
#include "sanitizer_common/sanitizer_flags.h"
Index: lib/asan/asan_thread.h
===================================================================
--- lib/asan/asan_thread.h
+++ lib/asan/asan_thread.h
@@ -17,7 +17,6 @@
#include "asan_allocator.h"
#include "asan_internal.h"
#include "asan_fake_stack.h"
-#include "asan_stack.h"
#include "asan_stats.h"
#include "sanitizer_common/sanitizer_common.h"
#include "sanitizer_common/sanitizer_libc.h"
Index: test/asan/TestCases/malloc_context_size.cc
===================================================================
--- test/asan/TestCases/malloc_context_size.cc
+++ test/asan/TestCases/malloc_context_size.cc
@@ -3,6 +3,7 @@
// RUN: ASAN_OPTIONS=malloc_context_size=0:fast_unwind_on_malloc=1 not %t 2>&1 | FileCheck %s --check-prefix=CHECK-%os
// RUN: ASAN_OPTIONS=malloc_context_size=1:fast_unwind_on_malloc=0 not %t 2>&1 | FileCheck %s --check-prefix=CHECK-%os
// RUN: ASAN_OPTIONS=malloc_context_size=1:fast_unwind_on_malloc=1 not %t 2>&1 | FileCheck %s --check-prefix=CHECK-%os
+// RUN: ASAN_OPTIONS=malloc_context_size=2 not %t 2>&1 | FileCheck %s --check-prefix=TWO
int main() {
char *x = new char[20];
@@ -24,4 +25,9 @@
// CHECK-NOT: #1 0x{{.*}}
// CHECK: SUMMARY: AddressSanitizer: heap-use-after-free
+
+ // TWO: previously allocated by thread T{{.*}} here:
+ // TWO-NEXT: #0 0x{{.*}}
+ // TWO-NEXT: #1 0x{{.*}} in main {{.*}}malloc_context_size.cc
+ // TWO: SUMMARY: AddressSanitizer: heap-use-after-free
}
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