[cfe-dev] [llvm-dev] How to debug if LTO generate wrong code?

[Shi, Steven via cfe-dev]

Hi Joerg,
My firmware case is I need load my firmware to run in high address which is hardware required. It is not that my firmware really need large static data and text code. My firmware modules are	 shared library (like a DLL) built with "-fpic", and firmware loader will load them to high address (larger than 2GB). I think this need is quite common to system software, like firmware, driver and kernel mode code.


Steven Shi
Intel\SSG\STO\UEFI Firmware

Tel: +86 021-61166522
iNet: 821-6522


> -----Original Message-----
> From: llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] On Behalf Of Joerg
> Sonnenberger via llvm-dev
> Sent: Monday, May 30, 2016 8:27 AM
> To: cfe-dev at lists.llvm.org; llvm-dev <llvm-dev at lists.llvm.org>
> Subject: Re: [llvm-dev] [cfe-dev] How to debug if LTO generate wrong code?
> 
> On Mon, May 30, 2016 at 12:10:09AM +0000, Shi, Steven via cfe-dev wrote:
> > I'm a bit surprised if both OS X ld64 and gold plugin do not support
> > large code model in LTO. Since modern system widely use the 64bit, the
> > code need to run in high address (larger than 2 GB) is a reasonable
> requirement.
> 
> Actually, given that PIC is (almost) free in terms of codegen, there is
> rarely a need for the large model on AMD64. Programs with more than 2GB
> of static data are moderately rare and programs with more than 2GB of
> text even more so.
> 
> Joerg
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