[Tooling] Drop leading/trailing whitespace from compile_flags.txt lines

[sammccall]

Summary

These files tend to be hand-authored, and people get very confused.
I can't think of any reason that such whitespace would be intended.

[kadircet]

thanks for remembering this :D

clang/test/Tooling/fixed-database.cpp

6

Not sure what this line is about, default comment marker is \0 for line_itearator and we don't seem to be changing it.

[sammccall]

clang/test/Tooling/fixed-database.cpp

6

Uh, this is a bad test, clang-check doesn't fail on driver errors and the compilation didn't depend on it.

And #comments would probably break something one day anyway.

clang/lib/Tooling/CompilationDatabase.cpp

 FixedCompilationDatabase::loadFromFile(StringRef Path, std::string &ErrorMsg) {
   ErrorMsg.clear();
   llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> File =
       llvm::MemoryBuffer::getFile(Path);
   if (std::error_code Result = File.getError()) {
     ErrorMsg = "Error while opening fixed database: " + Result.message();
     return nullptr;
   }
-  std::vector<std::string> Args{llvm::line_iterator(**File),
-                                llvm::line_iterator()};
+  std::vector<std::string> Args;
+  for (llvm::StringRef Line :
+       llvm::make_range(llvm::line_iterator(**File), llvm::line_iterator())) {
+    // Stray whitespace is almost certainly unintended.
+    Line = Line.trim();
+    if (!Line.empty())
+      Args.push_back(Line.str());
+  }
   return std::make_unique<FixedCompilationDatabase>(
       llvm::sys::path::parent_path(Path), std::move(Args));
 }
 
 FixedCompilationDatabase::
 FixedCompilationDatabase(Twine Directory, ArrayRef<std::string> CommandLine) {
   std::vector<std::string> ToolCommandLine(1, GetClangToolCommand());
   ToolCommandLine.insert(ToolCommandLine.end(),

clang/test/Tooling/fixed-database.cpp

 // RUN: rm -rf %t
 // RUN: mkdir -p %t/Src
 // RUN: cp "%s" "%t/Src/test.cpp"
 // RUN: mkdir -p %t/Include
 // RUN: cp "%S/Inputs/fixed-header.h" "%t/Include/"
 // -I flag is relative to %t (where compile_flags is), not Src/.
 // RUN: echo '-IInclude/' >> %t/compile_flags.txt
-// RUN: echo "-Dklazz=class" >> %t/compile_flags.txt
+// RUN: echo "  -Dklazz=class   " >> %t/compile_flags.txt
 // RUN: echo '-std=c++11' >> %t/compile_flags.txt
 // RUN: clang-check "%t/Src/test.cpp" 2>&1
 // RUN: echo > %t/compile_flags.txt
 // RUN: not clang-check "%t/Src/test.cpp" 2>&1 | FileCheck "%s" -check-prefix=NODB
 
 // NODB: unknown type name 'klazz'
 klazz F{};
 
 // NODB: 'fixed-header.h' file not found
 #include "fixed-header.h"
 static_assert(SECRET_SYMBOL == 1, "");