[PATCH] D52749: [LLD][COFF] Fix CRT global initializers

[Alexandre Ganea via Phabricator via llvm-commits]

aganea added a comment.

In https://reviews.llvm.org/D52749#1251704, @rnk wrote:

> In https://reviews.llvm.org/D52749#1251695, @aganea wrote:
>
> > Please note that this issue occurs only when using MSVC cl.exe. Compiling with clang-cl.exe does not expose the issue.
>
>
> I was going to say, I think clang generates a single initializer function to avoid relying on the linker's chosen section order.
>
> That's crummy, though. I guess we could limit it to the CRT section, and say anyone relying on section order corresponding to link line order in other sections is out of luck.


You're right indeed, that is the source of the bug. MSVC `cl.exe` does this:

  - Name:            '.CRT$XCU'
    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_LNK_COMDAT, IMAGE_SCN_MEM_READ ]
    Alignment:       8
    SectionData:     '0000000000000000'
    Relocations:     
      - VirtualAddress:  0
        SymbolName:      '??__E?Instances@?$TemplatedObject@$0A@@@2V?$vector at PEAU?$TemplatedObject@$0A@@@V?$allocator at PEAU?$TemplatedObject@$0A@@@@std@@@std@@A@@YAXXZ'
        Type:            IMAGE_REL_AMD64_ADDR64
  - Name:            '.CRT$XCU'
    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ ]
    Alignment:       8
    SectionData:     '0000000000000000'
    Relocations:     
      - VirtualAddress:  0
        SymbolName:      '??__Eidle@@YAXXZ'
        Type:            IMAGE_REL_AMD64_ADDR64

While `clang-cl` does this:

  - Name:            '.CRT$XCU'
    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ ]
    Alignment:       8
    SectionData:     '0000000000000000'
    Relocations:     
      - VirtualAddress:  0
        SymbolName:      _GLOBAL__sub_I_Source1.cpp
        Type:            IMAGE_REL_AMD64_ADDR64


Repository:
  rLLD LLVM Linker

https://reviews.llvm.org/D52749