[analyzer] Use lazily created buffer in EmptyLocalizationContextChecker

Fix a crash when relexing the underlying memory buffer to find incorrect
arguments to NSLocalizedString(). With precompiled headers, the raw
buffer may be NULL. Instead, use the source manager to get the buffer,
which will lazily create the buffer for precompiled headers.

rdar://problem/27429091

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@280174 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit cf632c9ffd8c80344aac9876748db66ddd9b516d)
diff --git a/lib/StaticAnalyzer/Checkers/LocalizationChecker.cpp b/lib/StaticAnalyzer/Checkers/LocalizationChecker.cpp
index 7be2f57..ca6567c 100644
--- a/lib/StaticAnalyzer/Checkers/LocalizationChecker.cpp
+++ b/lib/StaticAnalyzer/Checkers/LocalizationChecker.cpp
@@ -1001,6 +1001,8 @@
 void EmptyLocalizationContextChecker::MethodCrawler::VisitObjCMessageExpr(
     const ObjCMessageExpr *ME) {
 
+  // FIXME: We may be able to use PPCallbacks to check for empy context
+  // comments as part of preprocessing and avoid this re-lexing hack.
   const ObjCInterfaceDecl *OD = ME->getReceiverInterface();
   if (!OD)
     return;
@@ -1035,7 +1037,12 @@
     SE = Mgr.getSourceManager().getSLocEntry(SLInfo.first);
   }
 
-  llvm::MemoryBuffer *BF = SE.getFile().getContentCache()->getRawBuffer();
+  bool Invalid = false;
+  llvm::MemoryBuffer *BF =
+      Mgr.getSourceManager().getBuffer(SLInfo.first, SL, &Invalid);
+  if (Invalid)
+    return;
+
   Lexer TheLexer(SL, LangOptions(), BF->getBufferStart(),
                  BF->getBufferStart() + SLInfo.second, BF->getBufferEnd());
 
diff --git a/test/Analysis/Inputs/localization-pch.h b/test/Analysis/Inputs/localization-pch.h
new file mode 100644
index 0000000..973270e
--- /dev/null
+++ b/test/Analysis/Inputs/localization-pch.h
@@ -0,0 +1,5 @@
+// Used to test missing checker for missing localization context comments
+// in precompiled headers.
+
+#define MyLocalizedStringInPCH(key) NSLocalizedString((key), @"")
+
diff --git a/test/Analysis/localization-aggressive.m b/test/Analysis/localization-aggressive.m
index 79c9c13..89950d4 100644
--- a/test/Analysis/localization-aggressive.m
+++ b/test/Analysis/localization-aggressive.m
@@ -1,4 +1,6 @@
-// RUN: %clang_cc1 -analyze -fblocks -analyzer-store=region  -analyzer-checker=optin.osx.cocoa.localizability.NonLocalizedStringChecker -analyzer-checker=optin.osx.cocoa.localizability.EmptyLocalizationContextChecker -verify  -analyzer-config AggressiveReport=true %s
+// RUN: %clang_cc1 -fblocks -x objective-c-header -emit-pch -o %t.pch %S/Inputs/localization-pch.h
+
+// RUN: %clang_cc1 -analyze -fblocks -analyzer-store=region  -analyzer-checker=optin.osx.cocoa.localizability.NonLocalizedStringChecker -analyzer-checker=optin.osx.cocoa.localizability.EmptyLocalizationContextChecker -include-pch %t.pch -verify  -analyzer-config AggressiveReport=true %s
 
 // These declarations were reduced using Delta-Debugging from Foundation.h
 // on Mac OS X.
@@ -249,6 +251,10 @@
   NSString *string3 = NSLocalizedString((0 ? @"Critical" : @"Current"),nil); // expected-warning {{Localized string macro should include a non-empty comment for translators}}
 }
 
+- (void)testMacroExpansionDefinedInPCH {
+  NSString *string = MyLocalizedStringInPCH(@"Hello"); // expected-warning {{Localized string macro should include a non-empty comment for translators}}
+}
+
 #define KCLocalizedString(x,comment) NSLocalizedString(x, comment)
 #define POSSIBLE_FALSE_POSITIVE(s,other) KCLocalizedString(s,@"Comment")