[llvm-cov] Add the "Go to first unexecuted line" feature.

This patch provides easy navigation to find the zero count lines, especially useful when the source file is very large.

Differential Revision: https://reviews.llvm.org/D23277

llvm-svn: 280739
diff --git a/llvm/tools/llvm-cov/SourceCoverageView.cpp b/llvm/tools/llvm-cov/SourceCoverageView.cpp
index b61d791..323352a 100644
--- a/llvm/tools/llvm-cov/SourceCoverageView.cpp
+++ b/llvm/tools/llvm-cov/SourceCoverageView.cpp
@@ -82,6 +82,25 @@
   llvm_unreachable("Unknown coverage output format!");
 }
 
+unsigned SourceCoverageView::getFirstUncoveredLineNo() {
+  auto CheckIfUncovered = [](const coverage::CoverageSegment &S) {
+    return S.HasCount && S.Count == 0;
+  };
+  // L is less than R if (1) it's an uncovered segment (has a 0 count), and (2)
+  // either R is not an uncovered segment, or L has a lower line number than R.
+  const auto MinSegIt =
+      std::min_element(CoverageInfo.begin(), CoverageInfo.end(),
+                       [CheckIfUncovered](const coverage::CoverageSegment &L,
+                                          const coverage::CoverageSegment &R) {
+                         return (CheckIfUncovered(L) &&
+                                 (!CheckIfUncovered(R) || (L.Line < R.Line)));
+                       });
+  if (CheckIfUncovered(*MinSegIt))
+    return (*MinSegIt).Line;
+  // There is no uncovered line, return zero.
+  return 0;
+}
+
 std::string SourceCoverageView::formatCount(uint64_t N) {
   std::string Number = utostr(N);
   int Len = Number.size();
@@ -142,8 +161,12 @@
 
   renderViewHeader(OS);
 
+  unsigned FirstUncoveredLineNo = 0;
+  if (WholeFile)
+    FirstUncoveredLineNo = getFirstUncoveredLineNo();
+
   if (ShowSourceName)
-    renderSourceName(OS, WholeFile);
+    renderSourceName(OS, WholeFile, FirstUncoveredLineNo);
 
   renderTableHeader(OS, ViewDepth);
   // We need the expansions and instantiations sorted so we can go through them
diff --git a/llvm/tools/llvm-cov/SourceCoverageView.h b/llvm/tools/llvm-cov/SourceCoverageView.h
index eb820e3..410c8fd 100644
--- a/llvm/tools/llvm-cov/SourceCoverageView.h
+++ b/llvm/tools/llvm-cov/SourceCoverageView.h
@@ -175,6 +175,9 @@
   /// Specifies whether or not the view is a function view.
   bool FunctionView;
 
+  /// Get the first uncovered line number for the source file.
+  unsigned getFirstUncoveredLineNo();
+
 protected:
   struct LineRef {
     StringRef Line;
@@ -195,7 +198,8 @@
   virtual void renderViewFooter(raw_ostream &OS) = 0;
 
   /// \brief Render the source name for the view.
-  virtual void renderSourceName(raw_ostream &OS, bool WholeFile) = 0;
+  virtual void renderSourceName(raw_ostream &OS, bool WholeFile,
+                                unsigned FirstUncoveredLineNo) = 0;
 
   /// \brief Render the line prefix at the given \p ViewDepth.
   virtual void renderLinePrefix(raw_ostream &OS, unsigned ViewDepth) = 0;
diff --git a/llvm/tools/llvm-cov/SourceCoverageViewHTML.cpp b/llvm/tools/llvm-cov/SourceCoverageViewHTML.cpp
index 40bc650..7e069de 100644
--- a/llvm/tools/llvm-cov/SourceCoverageViewHTML.cpp
+++ b/llvm/tools/llvm-cov/SourceCoverageViewHTML.cpp
@@ -338,7 +338,8 @@
   OS << EndTable << EndCenteredDiv;
 }
 
-void SourceCoverageViewHTML::renderSourceName(raw_ostream &OS, bool WholeFile) {
+void SourceCoverageViewHTML::renderSourceName(raw_ostream &OS, bool WholeFile,
+                                              unsigned FirstUncoveredLineNo) {
   OS << BeginSourceNameDiv;
   // Render the source name for the view.
   std::string SourceFile = isFunctionView() ? "Function: " : "Source: ";
@@ -347,10 +348,18 @@
   sys::path::remove_dots(SourceText, /*remove_dot_dots=*/true);
   sys::path::native(SourceText);
   OS << tag("pre", escape(SourceText, getOptions()));
-  // Render the object file name for the view.
-  if (WholeFile)
+  if (WholeFile) {
+    // Render the object file name for the view.
     OS << tag("pre",
               escape("Binary: " + getOptions().ObjectFilename, getOptions()));
+    // Render the "Go to first unexecuted line" link for the view.
+    if (FirstUncoveredLineNo != 0) { // The file is not fully covered
+      std::string LinkText =
+          escape("Go to first unexecuted line", getOptions());
+      std::string LinkTarget = "#L" + utostr(uint64_t(FirstUncoveredLineNo));
+      OS << tag("pre", a(LinkTarget, LinkText));
+    }
+  }
   OS << EndSourceNameDiv;
 }
 
diff --git a/llvm/tools/llvm-cov/SourceCoverageViewHTML.h b/llvm/tools/llvm-cov/SourceCoverageViewHTML.h
index dd9f949..42fec6f 100644
--- a/llvm/tools/llvm-cov/SourceCoverageViewHTML.h
+++ b/llvm/tools/llvm-cov/SourceCoverageViewHTML.h
@@ -38,7 +38,8 @@
 
   void renderViewFooter(raw_ostream &OS) override;
 
-  void renderSourceName(raw_ostream &OS, bool WholeFile) override;
+  void renderSourceName(raw_ostream &OS, bool WholeFile,
+                        unsigned FirstUncoveredLineNo) override;
 
   void renderLinePrefix(raw_ostream &OS, unsigned ViewDepth) override;
 
diff --git a/llvm/tools/llvm-cov/SourceCoverageViewText.cpp b/llvm/tools/llvm-cov/SourceCoverageViewText.cpp
index 2f568b2..52e405e 100644
--- a/llvm/tools/llvm-cov/SourceCoverageViewText.cpp
+++ b/llvm/tools/llvm-cov/SourceCoverageViewText.cpp
@@ -63,7 +63,8 @@
 
 void SourceCoverageViewText::renderViewFooter(raw_ostream &) {}
 
-void SourceCoverageViewText::renderSourceName(raw_ostream &OS, bool WholeFile) {
+void SourceCoverageViewText::renderSourceName(raw_ostream &OS, bool WholeFile,
+                                              unsigned FirstUncoveredLineNo) {
   getOptions().colored_ostream(OS, raw_ostream::CYAN) << getSourceName()
                                                       << ":\n";
   if (WholeFile) {
diff --git a/llvm/tools/llvm-cov/SourceCoverageViewText.h b/llvm/tools/llvm-cov/SourceCoverageViewText.h
index fdf1a64..dd78d3a 100644
--- a/llvm/tools/llvm-cov/SourceCoverageViewText.h
+++ b/llvm/tools/llvm-cov/SourceCoverageViewText.h
@@ -38,7 +38,8 @@
 
   void renderViewFooter(raw_ostream &OS) override;
 
-  void renderSourceName(raw_ostream &OS, bool WholeFile) override;
+  void renderSourceName(raw_ostream &OS, bool WholeFile,
+                        unsigned FirstUncoveredLineNo) override;
 
   void renderLinePrefix(raw_ostream &OS, unsigned ViewDepth) override;