[analyzer] Consider switch- and goto- labels when constructing the set of executed lines

[george.karpenkov]

Summary

When viewing the report in the collapsed mode the label signifying where did the execution go is often necessary for properly understanding the context.

[NoQ]

Yep, looks reasonable.

cfe/trunk/lib/StaticAnalyzer/Core/BugReporter.cpp

static void populateExecutedLinesWithFunctionSignature(
   unsigned StartLine = SM.getExpansionLineNumber(Start);
   unsigned EndLine = SM.getExpansionLineNumber(End);
 
   FileID FID = SM.getFileID(SM.getExpansionLoc(Start));
   for (unsigned Line = StartLine; Line <= EndLine; Line++)
     ExecutedLines->operator[](FID.getHashValue()).insert(Line);
 }
 
+static void populateExecutedLinesWithStmt(
+    const Stmt *S, SourceManager &SM,
+    std::unique_ptr<FilesToLineNumsMap> &ExecutedLines) {
+  SourceLocation Loc = S->getSourceRange().getBegin();
+  SourceLocation ExpansionLoc = SM.getExpansionLoc(Loc);
+  FileID FID = SM.getFileID(ExpansionLoc);
+  unsigned LineNo = SM.getExpansionLineNumber(ExpansionLoc);
+  ExecutedLines->operator[](FID.getHashValue()).insert(LineNo);
+}
+
 /// \return all executed lines including function signatures on the path
 /// starting from \p N.
 static std::unique_ptr<FilesToLineNumsMap>
 findExecutedLines(SourceManager &SM, const ExplodedNode *N) {
   auto ExecutedLines = llvm::make_unique<FilesToLineNumsMap>();
 
   while (N) {
     if (N->getFirstPred() == nullptr) {
 
       // First node: show signature of the entrance point.
       const Decl *D = N->getLocationContext()->getDecl();
       populateExecutedLinesWithFunctionSignature(D, SM, ExecutedLines);
 
     } else if (auto CE = N->getLocationAs<CallEnter>()) {
 
       // Inlined function: show signature.
       const Decl* D = CE->getCalleeContext()->getDecl();
       populateExecutedLinesWithFunctionSignature(D, SM, ExecutedLines);
 
     } else if (const Stmt *S = PathDiagnosticLocation::getStmt(N)) {
+      populateExecutedLinesWithStmt(S, SM, ExecutedLines);
 
-      // Otherwise: show lines associated with the processed statement.
-      SourceLocation Loc = S->getSourceRange().getBegin();
-      SourceLocation ExpansionLoc = SM.getExpansionLoc(Loc);
-      FileID FID = SM.getFileID(ExpansionLoc);
-      unsigned LineNo = SM.getExpansionLineNumber(ExpansionLoc);
-      ExecutedLines->operator[](FID.getHashValue()).insert(LineNo);
+      // Show extra context for some parent kinds.
+      const Stmt *P = N->getParentMap().getParent(S);
+
+      // The path exploration can die before the node with the associated
+      // return statement is generated, but we do want to show the whole
+      // return.
+      if (auto *RS = dyn_cast_or_null<ReturnStmt>(P)) {
+        populateExecutedLinesWithStmt(RS, SM, ExecutedLines);
+        P = N->getParentMap().getParent(RS);
+      }
+
+      if (P && (isa<SwitchCase>(P) || isa<LabelStmt>(P)))
+        populateExecutedLinesWithStmt(P, SM, ExecutedLines);
     }
 
     N = N->getFirstPred();
   }
   return ExecutedLines;
 }
 
 void BugReporter::FlushReport(BugReport *exampleReport,

cfe/trunk/test/Analysis/html_diagnostics/relevant_lines/goto.c

+int goto_test(int input) {
+  int *p = 0;
+  if (input)
+    goto mylabel;
+  return 0;
+mylabel:
+  return *p;
+}
+
+// RUN: rm -rf %t.output
+// RUN: %clang_analyze_cc1 -analyze -analyzer-checker=core -analyzer-output html -o %t.output %s
+// RUN: cat %t.output/* | FileCheck %s --match-full-lines
+// CHECK: var relevant_lines = {"1": {"1": 1,  "2": 1, "3": 1, "4": 1, "6": 1, "7": 1}};

cfe/trunk/test/Analysis/html_diagnostics/relevant_lines/switch.c

+enum E {
+  A, B, C
+};
+
+int f(enum E input) {
+  int *x = 0;
+  switch (input) {
+    case A:
+      return 1;
+    case B:
+      return 0;
+    case C:
+      return *x;
+  }
+}
+
+// RUN: rm -rf %t.output
+// RUN: %clang_analyze_cc1 -analyze -analyzer-checker=core -analyzer-output html -o %t.output %s
+// RUN: cat %t.output/* | FileCheck %s --match-full-lines
+// CHECK: var relevant_lines = {"1": {"5": 1, "6": 1, "7": 1, "12": 1, "13": 1}};

cfe/trunk/test/Analysis/html_diagnostics/relevant_lines/switch_default.c

+enum E {
+  A, B, C
+};
+
+int f(enum E input) {
+  int *x = 0;
+  switch (input) {
+    case A:
+      return 1;
+    case B:
+      return 0;
+    default:
+      return *x;
+  }
+}
+
+// RUN: rm -rf %t.output
+// RUN: %clang_analyze_cc1 -analyze -analyzer-checker=core -analyzer-output html -o %t.output %s
+// RUN: cat %t.output/* | FileCheck %s --match-full-lines
+// CHECK: var relevant_lines = {"1": {"5": 1, "6": 1, "7": 1, "12": 1, "13": 1}};