llvm-cov: Added file checksum to gcno and gcda files.

Instead of permanently outputting "MVLL" as the file checksum, clang
will create gcno and gcda checksums by hashing the destination block
numbers of every arc. This allows for llvm-cov to check if the two gcov
files are synchronized.

Regenerated the test files so they contain the checksum. Also added
negative test to ensure error when the checksums don't match.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195191 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 0 deletions

diff --git a/lib/IR/GCOV.cpp b/lib/IR/GCOV.cpp
index 25a4ff669d..622c4f7851 100644
--- a/lib/IR/GCOV.cpp
+++ b/lib/IR/GCOV.cpp
@@ -46,6 +46,7 @@ bool GCOVFile::read(GCOVBuffer &Buffer) {
     return false;
 
   if (isGCNOFile(Format)) {
+    if (!Buffer.readInt(Checksum)) return false;
     while (true) {
       if (!Buffer.readFunctionTag()) break;
       GCOVFunction *GFun = new GCOVFunction();
@@ -55,6 +56,12 @@ bool GCOVFile::read(GCOVBuffer &Buffer) {
     }
   }
   else if (isGCDAFile(Format)) {
+    uint32_t Checksum2;
+    if (!Buffer.readInt(Checksum2)) return false;
+    if (Checksum != Checksum2) {
+      errs() << "File checksum does not match.\n";
+      return false;
+    }
     for (size_t i = 0, e = Functions.size(); i < e; ++i) {
       if (!Buffer.readFunctionTag()) {
         errs() << "Unexpected number of functions.\n";