[UBSan] Reduce the number of getCallerLocation() calls.

getCallerLocation() is expensive as it issues a call to symbolizer.
(In fact, this function has a memory leak at the moment, but this
will be fixed in the nearest future). We should only call it if
we're actually going to print an error report, in particular,
once for every reported source location.

__ubsan_handle_type_mismatch: call getCallerLocation() only if
provided source location is invalid, and only if the report is not
deduplicated.

__ubsan_handle_float_cast_overflow: call getSourceLocation with
correct CallerPC (the one in user code, not in UBSan handler). Source
location for this check is not currently emitted by frontend.

llvm-svn: 228732

compiler-rt/lib/ubsan/ubsan_diag.cc

@@ -66,25 +66,24 @@ class Decorator : public SanitizerCommonDecorator {
 };
 }
 
-Location __ubsan::getCallerLocation(uptr CallerLoc) {
-  if (!CallerLoc)
+Location __ubsan::getCallerLocation(uptr CallerPC) {
+  if (!CallerPC)
     return Location();
 
-  uptr Loc = StackTrace::GetPreviousInstructionPc(CallerLoc);
-  return getFunctionLocation(Loc, 0);
+  return getFunctionLocation(StackTrace::GetPreviousInstructionPc(CallerPC), 0);
 }
 
-Location __ubsan::getFunctionLocation(uptr Loc, const char **FName) {
-  if (!Loc)
+Location __ubsan::getFunctionLocation(uptr PC, const char **FName) {
+  if (!PC)
     return Location();
   InitIfNecessary();
 
-  SymbolizedStack *Frames = Symbolizer::GetOrInit()->SymbolizePC(Loc);
+  SymbolizedStack *Frames = Symbolizer::GetOrInit()->SymbolizePC(PC);
   const AddressInfo &Info = Frames->info;
 
   if (!Info.module) {
     Frames->ClearAll();
-    return Location(Loc);
+    return Location(PC);
   }
 
   if (FName && Info.function)

compiler-rt/lib/ubsan/ubsan_diag.h

@@ -80,13 +80,13 @@ public:
 
 /// Try to obtain a location for the caller. This might fail, and produce either
 /// an invalid location or a module location for the caller.
-Location getCallerLocation(uptr CallerLoc = GET_CALLER_PC());
+Location getCallerLocation(uptr CallerPC);
 
 /// Try to obtain a location for the given function pointer. This might fail,
 /// and produce either an invalid location or a module location for the caller.
 /// If FName is non-null and the name of the function is known, set *FName to
 /// the function name, otherwise *FName is unchanged.
-Location getFunctionLocation(uptr Loc, const char **FName);
+Location getFunctionLocation(uptr PC, const char **FName);
 
 /// A diagnostic severity level.
 enum DiagLevel {

compiler-rt/lib/ubsan/ubsan_handlers.cc

@@ -37,14 +37,14 @@ const char *TypeCheckKinds[] = {
 }
 
 static void handleTypeMismatchImpl(TypeMismatchData *Data, ValueHandle Pointer,
-                                   Location FallbackLoc, ReportOptions Opts) {
+                                   ReportOptions Opts) {
   Location Loc = Data->Loc.acquire();
   // Use the SourceLocation from Data to track deduplication, even if 'invalid'
   if (ignoreReport(Loc.getSourceLocation(), Opts))
     return;
 
   if (Data->Loc.isInvalid())
-    Loc = FallbackLoc;
+    Loc = getCallerLocation(Opts.pc);
 
   ScopedReport R(Opts, Loc);
 
@@ -67,12 +67,12 @@ static void handleTypeMismatchImpl(TypeMismatchData *Data, ValueHandle Pointer,
 void __ubsan::__ubsan_handle_type_mismatch(TypeMismatchData *Data,
                                            ValueHandle Pointer) {
   GET_REPORT_OPTIONS(false);
-  handleTypeMismatchImpl(Data, Pointer, getCallerLocation(), Opts);
+  handleTypeMismatchImpl(Data, Pointer, Opts);
 }
 void __ubsan::__ubsan_handle_type_mismatch_abort(TypeMismatchData *Data,
                                                  ValueHandle Pointer) {
   GET_REPORT_OPTIONS(true);
-  handleTypeMismatchImpl(Data, Pointer, getCallerLocation(), Opts);
+  handleTypeMismatchImpl(Data, Pointer, Opts);
   Die();
 }
 
@@ -288,7 +288,7 @@ void __ubsan::__ubsan_handle_vla_bound_not_positive_abort(VLABoundData *Data,
 static void handleFloatCastOverflow(FloatCastOverflowData *Data,
                                     ValueHandle From, ReportOptions Opts) {
   // TODO: Add deduplication once a SourceLocation is generated for this check.
-  Location Loc = getCallerLocation();
+  Location Loc = getCallerLocation(Opts.pc);
   ScopedReport R(Opts, Loc);
 
   Diag(Loc, DL_Error,