[TySan] Added a 'print_stacktrace' flag for more detailed errors

compiler-rt/lib/tysan/tysan.cpp

@@ -197,10 +197,14 @@ static void reportError(void *Addr, int Size, tysan_type_descriptor *TD,
     Printf("\n");
 
   if (pc) {
+    uptr top = 0;
+    uptr bottom = 0;
+    if (flags().print_stacktrace)
+      GetThreadStackTopAndBottom(false, &top, &bottom);
 
     bool request_fast = StackTrace::WillUseFastUnwind(true);
     BufferedStackTrace ST;
-    ST.Unwind(kStackTraceMax, pc, bp, 0, 0, 0, request_fast);
+    ST.Unwind(kStackTraceMax, pc, bp, 0, top, bottom, request_fast);
     ST.Print();
   } else {
     Printf("\n");

compiler-rt/lib/tysan/tysan_flags.inc

@@ -15,3 +15,6 @@
 
 // TYSAN_FLAG(Type, Name, DefaultValue, Description)
 // See COMMON_FLAG in sanitizer_flags.inc for more details.
+
+TYSAN_FLAG(bool, print_stacktrace, false,
+           "Include full stacktrace into an error report")

compiler-rt/test/tysan/print_stacktrace.c

@@ -0,0 +1,22 @@
+// RUN: %clang_tysan -O0 %s -o %t && %run %t >%t.out 2>&1
+// RUN: FileCheck --check-prefixes=CHECK,CHECK-SHORT %s < %t.out
+
+// RUN: %env_tysan_opts=print_stacktrace=1 %run %t >%t.out 2>&1
+// RUN: FileCheck --check-prefixes=CHECK,CHECK-LONG %s < %t.out
+
+float *P;
+void zero_array() {
+  int i;
+  for (i = 0; i < 1; ++i)
+    P[i] = 0.0f;
+  // CHECK: ERROR: TypeSanitizer: type-aliasing-violation
+  // CHECK: WRITE of size 4 at {{.*}} with type float accesses an existing object of type p1 float
+  // CHECK: {{#0 0x.* in zero_array .*print_stacktrace.c:}}[[@LINE-3]]
+  // CHECK-SHORT-NOT: {{#1 0x.* in main .*print_stacktrace.c}}
+  // CHECK-LONG-NEXT: {{#1 0x.* in main .*print_stacktrace.c}}
+}
+
+int main() {
+  P = (float *)&P;
+  zero_array();
+}