[llvm-cov] Avoid 0% when reporting something that's 0/0

This commit makes llvm-cov avoid showing 0% (0/0) coverage for things
like file function coverage, etc. in reports and HTML output. This can happen
for files like headers that have macros but no functions. This commit makes
llvm-cov report - (0/0) instead.

rdar://29246480

Differential Revision: https://reviews.llvm.org/D26615

llvm-svn: 287539

llvm/test/tools/llvm-cov/Inputs/zeroFunctionFile.h

@@ -0,0 +1,3 @@
+// This header has no functions
+
+#define NOFUNCTIONS(x) (x) > 0 ? 0 : 1

llvm/test/tools/llvm-cov/Inputs/zeroFunctionFile.proftext

@@ -0,0 +1,16 @@
+foo
+# Func Hash:
+13
+# Num Counters:
+2
+# Counter Values:
+1
+1
+
+main
+# Func Hash:
+0
+# Num Counters:
+1
+# Counter Values:
+1

llvm/test/tools/llvm-cov/zeroFunctionFile.c

@@ -0,0 +1,19 @@
+#include "Inputs/zeroFunctionFile.h"
+
+int foo(int x) {
+  return NOFUNCTIONS(x);
+}
+int main() {
+  return foo(2);
+}
+
+// RUN: llvm-profdata merge %S/Inputs/zeroFunctionFile.proftext -o %t.profdata
+
+// RUN: llvm-cov report %S/Inputs/zeroFunctionFile.covmapping -instr-profile %t.profdata 2>&1 | FileCheck --check-prefix=REPORT --strict-whitespace %s
+// REPORT: 0                 0         -           0                 0         -               0               0         -           0                 0         -
+// REPORT-NO: 0%
+
+// RUN: llvm-cov show %S/Inputs/zeroFunctionFile.covmapping -format html -instr-profile %t.profdata -o %t.dir
+// RUN: FileCheck %s -input-file=%t.dir/index.html -check-prefix=HTML
+// HTML: <td class='column-entry-green'><pre>- (0/0)
+// HTML-NO: 0.00% (0/0)

llvm/tools/llvm-cov/CoverageReport.cpp

@@ -154,36 +154,48 @@ void CoverageReport::render(const FileCoverageSummary &File,
                (unsigned)File.RegionCoverage.NumRegions);
   Options.colored_ostream(OS, FileCoverageColor) << format(
       "%*u", FileReportColumns[2], (unsigned)File.RegionCoverage.NotCovered);
+  if (File.RegionCoverage.NumRegions)
     Options.colored_ostream(OS, FileCoverageColor)
         << format("%*.2f", FileReportColumns[3] - 1,
                   File.RegionCoverage.getPercentCovered())
         << '%';
+  else
+    OS << column("-", FileReportColumns[3], Column::RightAlignment);
   OS << format("%*u", FileReportColumns[4],
                (unsigned)File.FunctionCoverage.NumFunctions);
   OS << format("%*u", FileReportColumns[5],
                (unsigned)(File.FunctionCoverage.NumFunctions -
                           File.FunctionCoverage.Executed));
+  if (File.FunctionCoverage.NumFunctions)
     Options.colored_ostream(OS, FuncCoverageColor)
         << format("%*.2f", FileReportColumns[6] - 1,
                   File.FunctionCoverage.getPercentCovered())
         << '%';
+  else
+    OS << column("-", FileReportColumns[6], Column::RightAlignment);
   OS << format("%*u", FileReportColumns[7],
                (unsigned)File.InstantiationCoverage.NumFunctions);
   OS << format("%*u", FileReportColumns[8],
                (unsigned)(File.InstantiationCoverage.NumFunctions -
                           File.InstantiationCoverage.Executed));
+  if (File.InstantiationCoverage.NumFunctions)
     Options.colored_ostream(OS, InstantiationCoverageColor)
         << format("%*.2f", FileReportColumns[9] - 1,
                   File.InstantiationCoverage.getPercentCovered())
         << '%';
+  else
+    OS << column("-", FileReportColumns[9], Column::RightAlignment);
   OS << format("%*u", FileReportColumns[10],
                (unsigned)File.LineCoverage.NumLines);
   Options.colored_ostream(OS, LineCoverageColor) << format(
       "%*u", FileReportColumns[11], (unsigned)File.LineCoverage.NotCovered);
+  if (File.LineCoverage.NumLines)
     Options.colored_ostream(OS, LineCoverageColor)
         << format("%*.2f", FileReportColumns[12] - 1,
                   File.LineCoverage.getPercentCovered())
         << '%';
+  else
+    OS << column("-", FileReportColumns[12], Column::RightAlignment);
   OS << "\n";
 }
 

llvm/tools/llvm-cov/SourceCoverageViewHTML.cpp

@@ -307,13 +307,17 @@ void CoveragePrinterHTML::emitFileSummary(raw_ostream &OS, StringRef SF,
     std::string S;
     {
       raw_string_ostream RSO{S};
-      RSO << format("%*.2f", 7, Pctg) << "% (" << Hit << '/' << Total << ')';
+      if (Total)
+        RSO << format("%*.2f", 7, Pctg) << "% ";
+      else
+        RSO << "- ";
+      RSO << '(' << Hit << '/' << Total << ')';
     }
     const char *CellClass = "column-entry-yellow";
-    if (Pctg < 80.0)
-      CellClass = "column-entry-red";
-    else if (Hit == Total)
+    if (Hit == Total)
       CellClass = "column-entry-green";
+    else if (Pctg < 80.0)
+      CellClass = "column-entry-red";
     Columns.emplace_back(tag("td", tag("pre", S), CellClass));
   };