[llvm-dev] why do undefined globals end up in .data instead of .bss? (original) (raw)

Friedman, Eli via llvm-dev llvm-dev at lists.llvm.org
Mon Apr 24 11:53:06 PDT 2017


On 4/23/2017 10:10 AM, Andrew Kelley via llvm-dev wrote:

Here is a module:

@vals = internal unnamedaddr global [20000000 x i32] undef, align 4 LLVM puts the global in the .data section, and results in a 77MB .o file of mostly zeroes. Why does this variable not go in the .bss section?

I think it's just an oversight; it doesn't matter for clang because it never emits globals like that. See TargetLoweringObjectFile::getKindForGlobal for the relevant logic.

-Eli

-- Employee of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project



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