[ubsan] Simplify ubsan_GetStackTrace

Suggested by Vitaly Buka

Author: MaskRay

compiler-rt/lib/ubsan/ubsan_diag.cpp

@@ -32,13 +32,9 @@ using namespace __ubsan;
 // Windows.
 // TODO(yln): This is a temporary workaround. GetStackTrace functions will be
 // removed in the future.
-void ubsan_GetStackTrace(BufferedStackTrace *stack, uptr max_depth, uptr pc,
-                         uptr bp, void *context, bool request_fast) {
-  uptr top = 0;
-  uptr bottom = 0;
-  GetThreadStackTopAndBottom(false, &top, &bottom);
-  bool fast = StackTrace::WillUseFastUnwind(request_fast);
-  stack->Unwind(max_depth, pc, bp, context, top, bottom, fast);
+void ubsan_GetStackTrace(BufferedStackTrace *stack, uptr pc, uptr bp,
+                         void *context, bool request_fast) {
+  stack->Unwind(pc, bp, context, request_fast);
 }
 
 static void MaybePrintStackTrace(uptr pc, uptr bp) {
@@ -48,8 +44,8 @@ static void MaybePrintStackTrace(uptr pc, uptr bp) {
     return;
 
   BufferedStackTrace stack;
-  ubsan_GetStackTrace(&stack, kStackTraceMax, pc, bp, nullptr,
-                common_flags()->fast_unwind_on_fatal);
+  ubsan_GetStackTrace(&stack, pc, bp, nullptr,
+                      common_flags()->fast_unwind_on_fatal);
   stack.Print();
 }
 

compiler-rt/lib/ubsan/ubsan_signals_standalone.cpp

@@ -38,15 +38,14 @@ void InitializeDeadlySignals() {}
 #include "sanitizer_common/sanitizer_signal_interceptors.inc"
 
 // TODO(yln): Temporary workaround. Will be removed.
-void ubsan_GetStackTrace(BufferedStackTrace *stack, uptr max_depth,
-                         uptr pc, uptr bp, void *context, bool fast);
+void ubsan_GetStackTrace(BufferedStackTrace *stack, uptr pc, uptr bp,
+                         void *context, bool fast);
 
 namespace __ubsan {
 
 static void OnStackUnwind(const SignalContext &sig, const void *,
                           BufferedStackTrace *stack) {
-  ubsan_GetStackTrace(stack, kStackTraceMax,
-                      StackTrace::GetNextInstructionPc(sig.pc), sig.bp,
+  ubsan_GetStackTrace(stack, StackTrace::GetNextInstructionPc(sig.pc), sig.bp,
                       sig.context, common_flags()->fast_unwind_on_fatal);
 }