[llvm-bugs] [Bug 27491] New: compiler response file isn't used when command line is close to response file limit

[via llvm-bugs]

https://llvm.org/bugs/show_bug.cgi?id=27491

            Bug ID: 27491
           Summary: compiler response file isn't used when command line is
                    close to response file limit
           Product: clang
           Version: 3.7
          Hardware: PC
                OS: Windows NT
            Status: NEW
          Severity: normal
          Priority: P
         Component: C++
          Assignee: unassignedclangbugs at nondot.org
          Reporter: dvaliant at ea.com
                CC: dgregor at apple.com, llvm-bugs at lists.llvm.org
    Classification: Unclassified

Description:

On windows 7 it appears clang calls itself as a subprocess when used to
compile. For short command lines subprocess is called with all arguments on
command line for large command lines a response file is used. However it
appears if command line used for subprocess is only just over the limit clang
will not use a response file when it should and fail with: 

clang++.exe : error : unable to execute command: Couldn't execute program
'C:\some\system\path\LLVM\bin\clang++.exe'The filename or extension is too
long.

Problem appears more frequently the longer the absolute path to clang++.exe

Repro:

- Call clang++.exe to compile any simple cpp file using a response file, use -v
argument to see if clang uses response file when calling clang subprocess
- artificially inflate response file by adding defines (e.g -D BLOAT) until you
see above error message (will happen close 32768 characters)
- if you see clang using response file try trimming response file by a
character at a time, the range is very small (bad range seems to be length of
executable path)

-- 
You are receiving this mail because:
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-bugs/attachments/20160422/133781cb/attachment.html>