[llvm] r202225 - Use StringRef in raw_fd_ostream constructor

[Alp Toker]

On 26/02/2014 03:21, Ben Langmuir wrote:
> Author: benlangmuir
> Date: Tue Feb 25 21:21:00 2014
> New Revision: 202225
>
> URL: http://llvm.org/viewvc/llvm-project?rev=202225&view=rev
> Log:
> Use StringRef in raw_fd_ostream constructor
>
> Modified:
>      llvm/trunk/include/llvm/Support/raw_ostream.h
>      llvm/trunk/lib/Support/raw_ostream.cpp
>
> Modified: llvm/trunk/include/llvm/Support/raw_ostream.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/raw_ostream.h?rev=202225&r1=202224&r2=202225&view=diff
> ==============================================================================
> --- llvm/trunk/include/llvm/Support/raw_ostream.h (original)
> +++ llvm/trunk/include/llvm/Support/raw_ostream.h Tue Feb 25 21:21:00 2014
> @@ -346,7 +346,7 @@ public:
>     /// itself to own the file descriptor. In particular, it will close the
>     /// file descriptor when it is done (this is necessary to detect
>     /// output errors).
> -  raw_fd_ostream(const char *Filename, std::string &ErrorInfo,
> +  raw_fd_ostream(StringRef Filename, std::string &ErrorInfo,
>                    sys::fs::OpenFlags Flags);

Filenames are a special case in LLVM that get passed around as an opaque 
const char* often without ever needing having their length measured 
(like the clang driver code I'm looking at right now).

Your change will incur a strlen() upon every ctor call: not a great 
problem, but also somewhat redundant -- was there a need that triggered 
this change?

Alp.

>   
>     /// raw_fd_ostream ctor - FD is the file descriptor that this writes to.  If
>
> Modified: llvm/trunk/lib/Support/raw_ostream.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/raw_ostream.cpp?rev=202225&r1=202224&r2=202225&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Support/raw_ostream.cpp (original)
> +++ llvm/trunk/lib/Support/raw_ostream.cpp Tue Feb 25 21:21:00 2014
> @@ -430,16 +430,15 @@ void format_object_base::home() {
>   /// occurs, information about the error is put into ErrorInfo, and the
>   /// stream should be immediately destroyed; the string will be empty
>   /// if no error occurred.
> -raw_fd_ostream::raw_fd_ostream(const char *Filename, std::string &ErrorInfo,
> +raw_fd_ostream::raw_fd_ostream(StringRef Filename, std::string &ErrorInfo,
>                                  sys::fs::OpenFlags Flags)
>       : Error(false), UseAtomicWrites(false), pos(0) {
> -  assert(Filename != 0 && "Filename is null");
>     ErrorInfo.clear();
>   
>     // Handle "-" as stdout. Note that when we do this, we consider ourself
>     // the owner of stdout. This means that we can do things like close the
>     // file descriptor when we're done and set the "binary" flag globally.
> -  if (Filename[0] == '-' && Filename[1] == 0) {
> +  if (Filename == "-") {
>       FD = STDOUT_FILENO;
>       // If user requested binary then put stdout into binary mode if
>       // possible.
>
>
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