PERL_NO_GET_CONTEXT+win32 fix #7
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On Win32 expat installs by default to "C:\Program Files\Expat 2.1.0" which has spaces, this makes compiling impossible since the cmd lines to CC and LD are broken.
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Can you clarify why "alot less Perl_get_context func calls" is a good thing pls? |
With VC 2013 32b -O1, with threaded perl 5.23.5, with C expat library in a separate DLL (no static linking), before this patch, Expat.dll was 47KB on disk, with a .text section size of 0x8BF0 bytes of x86 machine code, and 1616 call sites to Perl_get_context (on threaded unix perl, it would be pthread_getspecific isntead of Perl_get_context). After this patch, Expat.dll is 42 KB on disk, .text size is 0x7800 bytes, and Perl_get_context has 0 call sites (it isn't imported anymore).
ERRSV is a macro that contains a getter function call. Only plain vars or non function containing expressions can be placed in macros that evaluate their argument multiple times like SvTRUE (a dozen times) and SvPV (2 times). In this case Perl_gv_add_by_type which is a getter func inside ERRSV was called dozens and dozens of times inside externalEntityRef. Save the SV* to a C auto to prevent multiple getter function calls to Perl_gv_add_by_type. This decreases the .text section size of Expat.dll (VC2013 -O1, threaded perl, expat lib is a seperate DLL) from 0x7800 to 0x73E0 bytes of x86 machine code.
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Made the commit message more wordy and added another patch (again with a wordy message). PERL_NO_GET_CONTEXT makes absolutely no difference for unthreaded perls, since the perl engine is C global vars, and those C global vars cross shared lib boundaries, but on threaded perl, there are no C global vars, and the interp is stored in a malloc block, so there can be multiple interps in 1 process, therefore each interp needs its "my_perl" pointer, without PERL_NO_GET_CONTEXT, for source code backwards compatibility the perl engine pointer must be fetched from thread local storage with a function call every time it needed, which is atleast once in every single Perl API global var (PL_*) and macro, and function call, and typically half a dozen times per C statement. |
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Bump. |
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I probably won't have a release for a month or so. is this a rush? |
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No, but I would like it to be released early enough to make into Active and Strawberry Perl 5.24 (before spring 2016), so Im fine with waiting a month. |
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Could you please merge this to your master so I can delete my repo? |
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I'm having to revert this. Your code doesn't function when PERL_IMPLICIT_CONTEXT isn't defined. It isn't always and in point of fact, travis doesn't define it. |
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