[compiler-rt] Add SourceLocations for float_cast_overflow data.

Summary:
Compiler-rt part of http://reviews.llvm.org/D11757
I ended up making UBSan work with both the old version and the new
version of the float_cast_overflow data (instead of just erroring with
the previous version). The old version will try to symbolize its caller.

Now we compile the float_cast_overflow tests without -g, and make sure
we have the source file+line+column.

If you think I'm trying too hard to make sure we can still use both
versions, let me know.

Reviewers: samsonov, rsmith

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D11793

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@244567 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 53 insertions, 14 deletions

diff --git a/lib/ubsan/ubsan_handlers.cc b/lib/ubsan/ubsan_handlers.cc
index a65b2f5e3..1e8fee355 100644
--- a/lib/ubsan/ubsan_handlers.cc
+++ b/lib/ubsan/ubsan_handlers.cc
@@ -290,26 +290,57 @@ void __ubsan::__ubsan_handle_vla_bound_not_positive_abort(VLABoundData *Data,
   Die();
 }
 
-static void handleFloatCastOverflow(FloatCastOverflowData *Data,
-                                    ValueHandle From, ReportOptions Opts) {
-  // TODO: Add deduplication once a SourceLocation is generated for this check.
-  SymbolizedStackHolder CallerLoc(getCallerLocation(Opts.pc));
-  Location Loc = CallerLoc;
+static bool looksLikeFloatCastOverflowDataV1(void *Data) {
+  // First field is either a pointer to filename or a pointer to a
+  // TypeDescriptor.
+  u8 *FilenameOrTypeDescriptor;
+  internal_memcpy(&FilenameOrTypeDescriptor, Data,
+                  sizeof(FilenameOrTypeDescriptor));
+
+  // Heuristic: For float_cast_overflow, the TypeKind will be either TK_Integer
+  // (0x0) or TK_Float (0x1). Adding both bytes will be 0 or 1 (for BE or LE).
+  // If it were a filename, adding two printable characters will not yield such
+  // a value.
+  u16 MaybeFromTypeKind =
+      FilenameOrTypeDescriptor[0] + FilenameOrTypeDescriptor[1];
+  return MaybeFromTypeKind < 2;
+}
+
+static void handleFloatCastOverflow(void *DataPtr, ValueHandle From,
+                                    ReportOptions Opts) {
+  SymbolizedStackHolder CallerLoc;
+  Location Loc;
+  const TypeDescriptor *FromType, *ToType;
+
+  if (looksLikeFloatCastOverflowDataV1(DataPtr)) {
+    auto Data = reinterpret_cast<FloatCastOverflowData *>(DataPtr);
+    CallerLoc.reset(getCallerLocation(Opts.pc));
+    Loc = CallerLoc;
+    FromType = &Data->FromType;
+    ToType = &Data->ToType;
+  } else {
+    auto Data = reinterpret_cast<FloatCastOverflowDataV2 *>(DataPtr);
+    SourceLocation SLoc = Data->Loc.acquire();
+    if (ignoreReport(SLoc, Opts))
+      return;
+    Loc = SLoc;
+    FromType = &Data->FromType;
+    ToType = &Data->ToType;
+  }
+
   ScopedReport R(Opts, Loc);
 
   Diag(Loc, DL_Error,
        "value %0 is outside the range of representable values of type %2")
-      << Value(Data->FromType, From) << Data->FromType << Data->ToType;
+      << Value(*FromType, From) << *FromType << *ToType;
 }
 
-void __ubsan::__ubsan_handle_float_cast_overflow(FloatCastOverflowData *Data,
-                                                 ValueHandle From) {
+void __ubsan::__ubsan_handle_float_cast_overflow(void *Data, ValueHandle From) {
   GET_REPORT_OPTIONS(false);
   handleFloatCastOverflow(Data, From, Opts);
 }
-void
-__ubsan::__ubsan_handle_float_cast_overflow_abort(FloatCastOverflowData *Data,
-                                                  ValueHandle From) {
+void __ubsan::__ubsan_handle_float_cast_overflow_abort(void *Data,
+                                                       ValueHandle From) {
   GET_REPORT_OPTIONS(true);
   handleFloatCastOverflow(Data, From, Opts);
   Die();
diff --git a/lib/ubsan/ubsan_handlers.h b/lib/ubsan/ubsan_handlers.h
index 87149f259..25093d432 100644
--- a/lib/ubsan/ubsan_handlers.h
+++ b/lib/ubsan/ubsan_handlers.h
@@ -97,14 +97,22 @@ struct VLABoundData {
 /// \brief Handle a VLA with a non-positive bound.
 RECOVERABLE(vla_bound_not_positive, VLABoundData *Data, ValueHandle Bound)
 
+// Keeping this around for binary compatibility with (sanitized) programs
+// compiled with older compilers.
 struct FloatCastOverflowData {
-  // FIXME: SourceLocation Loc;
   const TypeDescriptor &FromType;
   const TypeDescriptor &ToType;
 };
 
-/// \brief Handle overflow in a conversion to or from a floating-point type.
-RECOVERABLE(float_cast_overflow, FloatCastOverflowData *Data, ValueHandle From)
+struct FloatCastOverflowDataV2 {
+  SourceLocation Loc;
+  const TypeDescriptor &FromType;
+  const TypeDescriptor &ToType;
+};
+
+/// Handle overflow in a conversion to or from a floating-point type.
+/// void *Data is one of FloatCastOverflowData* or FloatCastOverflowDataV2*
+RECOVERABLE(float_cast_overflow, void *Data, ValueHandle From)
 
 struct InvalidValueData {
   SourceLocation Loc;