address comments

Author: ziqingluo-90

clang/lib/StaticAnalyzer/Core/CheckerHelpers.cpp

@@ -134,14 +134,14 @@ std::optional<int> tryExpandAsInteger(StringRef Macro, const Preprocessor &PP) {
     return std::nullopt;
 
   bool InvalidSpelling = false;
+  SmallVector<char> Buffer(T.getLength());
   // `Preprocessor::getSpelling` can get the spelling of the token regardless of
   // whether the macro is defined in a PCH or not:
-  std::string Spelling = PP.getSpelling(T, &InvalidSpelling);
+  StringRef ValueStr = PP.getSpelling(T, Buffer, &InvalidSpelling);
 
   if (InvalidSpelling)
     return std::nullopt;
 
-  StringRef ValueStr(Spelling);
   llvm::APInt IntValue;
   constexpr unsigned AutoSenseRadix = 0;
   if (ValueStr.getAsInteger(AutoSenseRadix, IntValue))

clang/test/Analysis/pch_macro.cpp

@@ -1,15 +1,19 @@
-// RUN: %clang_cc1 -triple x86_64-apple-macosx10.15.0 -emit-pch -o %t %s
-// RUN: %clang_analyze_cc1 -triple x86_64-apple-macosx10.15.0 -include-pch %t \
-// RUN:   -analyzer-checker=core,apiModeling,unix.StdCLibraryFunctions -verify %s
+// RUN: rm -rf %t
+// RUN: mkdir -p %t
+// RUN: split-file %s %t
+
+// RUN: %clang_cc1 -x c++ -triple x86_64-apple-macosx10.15.0 -emit-pch -o %t/header.pch %t/header.h
+// RUN: %clang_analyze_cc1 -triple x86_64-apple-macosx10.15.0 -include-pch %t/header.pch \
+// RUN:   -analyzer-checker=core,apiModeling,unix.StdCLibraryFunctions -verify %t/main.cpp
 //
-// RUN: %clang_cc1 -emit-pch -o %t %s
-// RUN: %clang_analyze_cc1 -include-pch %t \
-// RUN:   -analyzer-checker=core,apiModeling,unix.StdCLibraryFunctions -verify %s
+// RUN: %clang_cc1 -x c++ -emit-pch -o %t/header.pch %t/header.h
+// RUN: %clang_analyze_cc1 -include-pch %t/header.pch \
+// RUN:   -analyzer-checker=core,apiModeling,unix.StdCLibraryFunctions -verify %t/main.cpp
+
+
+//--- header.h
 
-// expected-no-diagnostics
 
-#ifndef HEADER
-#define HEADER
 // Pre-compiled header
 
 int foo();
@@ -18,9 +22,12 @@ int foo();
 #define EOF -1
 #define AT_FDCWD -2
 
-#else
-// Source file
 
+//--- main.cpp
+
+
+// Source file
+// expected-no-diagnostics
 int test() {
   // we need a function call here to initiate erroneous routine
   return foo(); // no-crash
@@ -36,4 +43,3 @@ void test_faccessat() {
   if (0 != faccessat(AT_FDCWD, fileSystemPath, 2, 0x0030)) {}
 }
 
-#endif