[llvm-cov] Use uint64_t to avoid overflow in addition

[alanphipps]

LGTM thanks

llvm/tools/llvm-cov/SourceCoverageViewText.cpp

235

Thanks for catching this. I believe CoverageSummaryInfo.cpp uses size_t to add the counters, but I am OK with using uint64_t for the source coverage views.

llvm/tools/llvm-cov/SourceCoverageViewHTML.cpp

if (getOptions().Debug)
     errs() << "Branch at line " << BRV.getLine() << '\n';
 
   OS << BeginExpansionDiv;
   OS << BeginPre;
   for (const auto &R : BRV.Regions) {
     // Calculate TruePercent and False Percent.
     double TruePercent = 0.0;
     double FalsePercent = 0.0;
-    unsigned Total = R.ExecutionCount + R.FalseExecutionCount;
+    // FIXME: It may overflow when the data is too large, but I have not
+    // encountered it in actual use, and not sure whether to use __uint128_t.
+    uint64_t Total = R.ExecutionCount + R.FalseExecutionCount;
 
     if (!getOptions().ShowBranchCounts && Total != 0) {
       TruePercent = ((double)(R.ExecutionCount) / (double)Total) * 100.0;
       FalsePercent = ((double)(R.FalseExecutionCount) / (double)Total) * 100.0;
     }
 
     // Display Line + Column.
     std::string LineNoStr = utostr(uint64_t(R.LineStart));

llvm/tools/llvm-cov/SourceCoverageViewText.cpp

void SourceCoverageViewText::renderBranchView(raw_ostream &OS, BranchView &BRV,
                                               unsigned ViewDepth) {
   // Render the child subview.
   if (getOptions().Debug)
     errs() << "Branch at line " << BRV.getLine() << '\n';
 
   for (const auto &R : BRV.Regions) {
     double TruePercent = 0.0;
     double FalsePercent = 0.0;
-    unsigned Total = R.ExecutionCount + R.FalseExecutionCount;
+    // FIXME: It may overflow when the data is too large, but I have not
+    // encountered it in actual use, and not sure whether to use __uint128_t.
+    uint64_t Total = R.ExecutionCount + R.FalseExecutionCount;
 
     if (!getOptions().ShowBranchCounts && Total != 0) {
       TruePercent = ((double)(R.ExecutionCount) / (double)Total) * 100.0;
       FalsePercent = ((double)(R.FalseExecutionCount) / (double)Total) * 100.0;
     }
 
     renderLinePrefix(OS, ViewDepth);
     OS << "  Branch (" << R.LineStart << ":" << R.ColumnStart << "): [";