[Frontend] Verify that the bitstream is not empty before reading

the serialised diagnostics Clang should avoid calling report_fatal_error when the file with the serialised diagnostics is empty. This commit changes Clang's serialised diagnostic reader, now it reports an appropriate error instead of crashing. rdar://31939877 Differential Revision: https://reviews.llvm.org/D35069 git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@307384 91177308-0d34-0410-b5e6-96231b3b80d8
Mokolea · Jul 7, 2017 · a43da82 · a43da82
1 parent ebbbc9c
commit a43da82
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diff --git a/lib/Frontend/SerializedDiagnosticReader.cpp b/lib/Frontend/SerializedDiagnosticReader.cpp
@@ -27,6 +27,9 @@ std::error_code SerializedDiagnosticReader::readDiagnostics(StringRef File) {
   llvm::BitstreamCursor Stream(**Buffer);
   Optional<llvm::BitstreamBlockInfo> BlockInfo;
 
+  if (Stream.AtEndOfStream())
+    return SDError::InvalidSignature;
+
   // Sniff for the signature.
   if (Stream.Read(8) != 'D' ||
       Stream.Read(8) != 'I' ||

diff --git a/test/Index/Inputs/empty.dia b/test/Index/Inputs/empty.dia
diff --git a/test/Index/read-empty-diags.test b/test/Index/read-empty-diags.test
@@ -0,0 +1,2 @@
+// RUN: not c-index-test -read-diagnostics %S/Inputs/empty.dia 2>&1 | FileCheck %s
+// CHECK: Trouble deserializing file (Invalid File): Invalid diagnostics signature
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		// RUN: not c-index-test -read-diagnostics %S/Inputs/empty.dia 2>&1 \| FileCheck %s
		// CHECK: Trouble deserializing file (Invalid File): Invalid diagnostics signature