[Sanitizer] Simplify StackTrace::FastUnwindStack interface and fix a bug with one-frame stack traces

llvm-svn: 192428

6 files changed, 34 insertions, 30 deletions

diff --git a/compiler-rt/lib/msan/msan.cc b/compiler-rt/lib/msan/msan.cc
index 6b52c727330..aebbd052b2a 100644
--- a/compiler-rt/lib/msan/msan.cc
+++ b/compiler-rt/lib/msan/msan.cc
@@ -190,10 +190,7 @@ void GetStackTrace(StackTrace *stack, uptr max_s, uptr pc, uptr bp,
 
   uptr stack_top, stack_bottom;
   GetCurrentStackBounds(&stack_top, &stack_bottom);
-  stack->size = 0;
-  stack->trace[0] = pc;
-  stack->max_size = max_s;
-  stack->FastUnwindStack(pc, bp, stack_top, stack_bottom);
+  stack->FastUnwindStack(pc, bp, stack_top, stack_bottom, max_s);
 }
 
 void PrintWarning(uptr pc, uptr bp) {
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_flags.cc b/compiler-rt/lib/sanitizer_common/sanitizer_flags.cc
index 7342261672e..036f97b9d51 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_flags.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_flags.cc
@@ -32,6 +32,10 @@ void ParseCommonFlagsFromString(const char *str) {
   ParseFlag(str, &f->detect_leaks, "detect_leaks");
   ParseFlag(str, &f->leak_check_at_exit, "leak_check_at_exit");
   ParseFlag(str, &f->allocator_may_return_null, "allocator_may_return_null");
+
+  // Do a sanity check for certain flags.
+  if (f->malloc_context_size < 1)
+    f->malloc_context_size = 1;
 }
 
 static bool GetFlagValue(const char *env, const char *name,
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cc b/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cc
index 429f5de28f7..24ba3caf5d7 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cc
@@ -92,22 +92,16 @@ int internal_isatty(fd_t fd) {
 #ifndef SANITIZER_GO
 void GetStackTrace(StackTrace *stack, uptr max_s, uptr pc, uptr bp,
                    uptr stack_top, uptr stack_bottom, bool fast) {
-#if !SANITIZER_CAN_FAST_UNWIND
-  fast = false;
-#endif
-#if SANITIZER_MAC
-  // Always unwind fast on Mac.
-  (void)fast;
-#else
+  // Check if fast unwind is available. Fast unwind is the only option on Mac.
+  if (!SANITIZER_CAN_FAST_UNWIND)
+    fast = false;
+  else if (SANITIZER_MAC)
+    fast = true;
+
   if (!fast)
-    return stack->SlowUnwindStack(pc, max_s);
-#endif  // SANITIZER_MAC
-  stack->size = 0;
-  stack->trace[0] = pc;
-  if (max_s > 1) {
-    stack->max_size = max_s;
-    stack->FastUnwindStack(pc, bp, stack_top, stack_bottom);
-  }
+    stack->SlowUnwindStack(pc, max_s);
+  else
+    stack->FastUnwindStack(pc, bp, stack_top, stack_bottom, max_s);
 }
 #endif  // SANITIZER_GO
 
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cc b/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cc
index e9ecfc9c5e0..a87b647ad45 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cc
@@ -106,8 +106,14 @@ uptr StackTrace::GetCurrentPc() {
 }
 
 void StackTrace::FastUnwindStack(uptr pc, uptr bp,
-                                 uptr stack_top, uptr stack_bottom) {
-  CHECK(size == 0 && trace[0] == pc);
+                                 uptr stack_top, uptr stack_bottom,
+                                 uptr max_depth) {
+  max_size = max_depth;
+  if (max_size == 0) {
+    size = 0;
+    return;
+  }
+  trace[0] = pc;
   size = 1;
   uhwptr *frame = (uhwptr *)bp;
   uhwptr *prev_frame = frame - 1;
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.h b/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.h
index b2e0d6b5f3d..b9ada16d06b 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.h
@@ -51,7 +51,8 @@ struct StackTrace {
     }
   }
 
-  void FastUnwindStack(uptr pc, uptr bp, uptr stack_top, uptr stack_bottom);
+  void FastUnwindStack(uptr pc, uptr bp, uptr stack_top, uptr stack_bottom,
+                       uptr max_depth);
   void SlowUnwindStack(uptr pc, uptr max_depth);
 
   void PopStackFrames(uptr count);
diff --git a/compiler-rt/lib/sanitizer_common/tests/sanitizer_stacktrace_test.cc b/compiler-rt/lib/sanitizer_common/tests/sanitizer_stacktrace_test.cc
index 3d352cb97a5..82c4426d8f8 100644
--- a/compiler-rt/lib/sanitizer_common/tests/sanitizer_stacktrace_test.cc
+++ b/compiler-rt/lib/sanitizer_common/tests/sanitizer_stacktrace_test.cc
@@ -47,16 +47,11 @@ void FastUnwindTest::SetUp() {
   // Bottom is one slot before the start because FastUnwindStack uses >.
   fake_bottom = (uptr)&fake_stack[-1];
   start_pc = PC(0);
-
-  // This is common setup done by __asan::GetStackTrace().
-  trace.size = 0;
-  trace.max_size = ARRAY_SIZE(fake_stack);
-  trace.trace[0] = start_pc;
 }
 
 TEST_F(FastUnwindTest, Basic) {
   trace.FastUnwindStack(start_pc, (uptr)&fake_stack[0],
-                        fake_top, fake_bottom);
+                        fake_top, fake_bottom, kStackTraceMax);
   // Should get all on-stack retaddrs and start_pc.
   EXPECT_EQ(6U, trace.size);
   EXPECT_EQ(start_pc, trace.trace[0]);
@@ -70,7 +65,7 @@ TEST_F(FastUnwindTest, FramePointerLoop) {
   // Make one fp point to itself.
   fake_stack[4] = (uptr)&fake_stack[4];
   trace.FastUnwindStack(start_pc, (uptr)&fake_stack[0],
-                        fake_top, fake_bottom);
+                        fake_top, fake_bottom, kStackTraceMax);
   // Should get all on-stack retaddrs up to the 4th slot and start_pc.
   EXPECT_EQ(4U, trace.size);
   EXPECT_EQ(start_pc, trace.trace[0]);
@@ -83,7 +78,7 @@ TEST_F(FastUnwindTest, MisalignedFramePointer) {
   // Make one fp misaligned.
   fake_stack[4] += 3;
   trace.FastUnwindStack(start_pc, (uptr)&fake_stack[0],
-                        fake_top, fake_bottom);
+                        fake_top, fake_bottom, kStackTraceMax);
   // Should get all on-stack retaddrs up to the 4th slot and start_pc.
   EXPECT_EQ(4U, trace.size);
   EXPECT_EQ(start_pc, trace.trace[0]);
@@ -92,5 +87,12 @@ TEST_F(FastUnwindTest, MisalignedFramePointer) {
   }
 }
 
+TEST_F(FastUnwindTest, OneFrameStackTrace) {
+  trace.FastUnwindStack(start_pc, (uptr)&fake_stack[0],
+                        fake_top, fake_bottom, 1);
+  EXPECT_EQ(1U, trace.size);
+  EXPECT_EQ(1U, trace.max_size);
+  EXPECT_EQ(start_pc, trace.trace[0]);
+}
 
 }  // namespace __sanitizer