From 0509d047f4f1b742042b78426f84e48c94659ff5 Mon Sep 17 00:00:00 2001
From: Anton Yartsev <anton.yartsev@gmail.com>
Date: Thu, 6 Oct 2016 21:42:21 +0000
Subject: [PATCH] [analyzer] Add explanation why analyzer report is not
 generated (fix for PR12421).

Currently if the path diagnostic consumer (e.g HTMLDiagnostics and PlistDiagnostics) do not support cross file diagnostics then the path diagnostic report is silently omitted in the case of cross file diagnostics. The patch adds a little verbosity to Clang in this case.
The patch also adds help entry for the "--analyzer-output" driver option.

llvm-svn: 283499
---
 clang/include/clang/Driver/Options.td         |  3 ++-
 .../StaticAnalyzer/Core/PathDiagnostic.cpp    | 24 ++++++++++++++-----
 .../diagnostics/diag-cross-file-boundaries.c  | 12 ++++++++++
 .../diagnostics/diag-cross-file-boundaries.h  |  4 ++++
 4 files changed, 36 insertions(+), 7 deletions(-)
 create mode 100644 clang/test/Analysis/diagnostics/diag-cross-file-boundaries.c
 create mode 100644 clang/test/Analysis/diagnostics/diag-cross-file-boundaries.h

diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 2ff4739b94f5..a6b006108fc9 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -2005,7 +2005,8 @@ def _CLASSPATH : Separate<["--"], "CLASSPATH">, Alias<fclasspath_EQ>;
 def _all_warnings : Flag<["--"], "all-warnings">, Alias<Wall>;
 def _analyze_auto : Flag<["--"], "analyze-auto">, Flags<[DriverOption]>;
 def _analyzer_no_default_checks : Flag<["--"], "analyzer-no-default-checks">, Flags<[DriverOption]>;
-def _analyzer_output : JoinedOrSeparate<["--"], "analyzer-output">, Flags<[DriverOption]>;
+def _analyzer_output : JoinedOrSeparate<["--"], "analyzer-output">, Flags<[DriverOption]>,
+  HelpText<"Static analyzer report output format (html|plist|plist-multi-file|plist-html|text).">;
 def _analyze : Flag<["--"], "analyze">, Flags<[DriverOption, CoreOption]>,
   HelpText<"Run the static analyzer">;
 def _assemble : Flag<["--"], "assemble">, Alias<S>;
diff --git a/clang/lib/StaticAnalyzer/Core/PathDiagnostic.cpp b/clang/lib/StaticAnalyzer/Core/PathDiagnostic.cpp
index 217d628a129c..9d2f7e8c2e87 100644
--- a/clang/lib/StaticAnalyzer/Core/PathDiagnostic.cpp
+++ b/clang/lib/StaticAnalyzer/Core/PathDiagnostic.cpp
@@ -211,6 +211,12 @@ void PathDiagnosticConsumer::HandlePathDiagnostic(
     const SourceManager &SMgr = D->path.front()->getLocation().getManager();
     SmallVector<const PathPieces *, 5> WorkList;
     WorkList.push_back(&D->path);
+    SmallString<128> buf;
+    llvm::raw_svector_ostream warning(buf);
+    warning << "warning: Path diagnostic report is not generated. Current "
+            << "output format does not support diagnostics that cross file "
+            << "boundaries. Refer to --analyzer-output for valid output "
+            << "formats\n";
 
     while (!WorkList.empty()) {
       const PathPieces &path = *WorkList.pop_back_val();
@@ -222,19 +228,25 @@ void PathDiagnosticConsumer::HandlePathDiagnostic(
 
         if (FID.isInvalid()) {
           FID = SMgr.getFileID(L);
-        } else if (SMgr.getFileID(L) != FID)
-          return; // FIXME: Emit a warning?
+        } else if (SMgr.getFileID(L) != FID) {
+          llvm::errs() << warning.str();
+          return;
+        }
 
         // Check the source ranges.
         ArrayRef<SourceRange> Ranges = piece->getRanges();
         for (ArrayRef<SourceRange>::iterator I = Ranges.begin(),
                                              E = Ranges.end(); I != E; ++I) {
           SourceLocation L = SMgr.getExpansionLoc(I->getBegin());
-          if (!L.isFileID() || SMgr.getFileID(L) != FID)
-            return; // FIXME: Emit a warning?
+          if (!L.isFileID() || SMgr.getFileID(L) != FID) {
+            llvm::errs() << warning.str();
+            return;
+          }
           L = SMgr.getExpansionLoc(I->getEnd());
-          if (!L.isFileID() || SMgr.getFileID(L) != FID)
-            return; // FIXME: Emit a warning?
+          if (!L.isFileID() || SMgr.getFileID(L) != FID) {
+            llvm::errs() << warning.str();
+            return;
+          }
         }
 
         if (const PathDiagnosticCallPiece *call =
diff --git a/clang/test/Analysis/diagnostics/diag-cross-file-boundaries.c b/clang/test/Analysis/diagnostics/diag-cross-file-boundaries.c
new file mode 100644
index 000000000000..270163e85607
--- /dev/null
+++ b/clang/test/Analysis/diagnostics/diag-cross-file-boundaries.c
@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 -analyze -analyzer-checker=core -verify %s
+// RUN: %clang_cc1 -analyze -analyzer-checker=core -analyzer-output=html -o PR12421.html %s 2>&1 | FileCheck %s
+
+// Test for PR12421
+#include "diag-cross-file-boundaries.h"
+
+int main(){
+  f();
+  return 0;
+}
+
+// CHECK: warning: Path diagnostic report is not generated.
diff --git a/clang/test/Analysis/diagnostics/diag-cross-file-boundaries.h b/clang/test/Analysis/diagnostics/diag-cross-file-boundaries.h
new file mode 100644
index 000000000000..1af7d1f1fbb4
--- /dev/null
+++ b/clang/test/Analysis/diagnostics/diag-cross-file-boundaries.h
@@ -0,0 +1,4 @@
+static void f() {
+  int *p = 0;
+  *p = 1;       // expected-warning{{Dereference of null pointer}}
+}