[llvm-dev] Risc-v Assembly printer function order

[via llvm-dev]

> -----Original Message-----
> From: llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] On Behalf Of
> Friedman, Eli via llvm-dev
> Sent: Tuesday, August 07, 2018 1:58 PM
> To: 'Irenee GROZ IG255340'; llvm-dev at lists.llvm.org
> Subject: Re: [llvm-dev] Risc-v Assembly printer function order
> 
> On 8/7/2018 12:54 AM, 'Irenee GROZ IG255340' via llvm-dev wrote:
> > Hello,
> >
> > I am working on the assembly printer for RISC-V, more specifically on
> > the AsmPrinter class.
> > I altered the RISCV Backend to print C code instead of Assembly,
> > interpreted by libraries... (but that's not important)
> > My problem is that, for my application to work, I need to treat my
> > functions in the order they are in the original C file.
> > I discovered that these functions are not treated in this order.
> >
> > My question is : Is there a way to force llvm to treat the functions
> > in the order given in the original C file ? and how?
> 
> The LLVM backend should generally print functions in the same order they
> appear in the IR.  This is an implementation detail, not a guarantee,
> but there currently aren't any backend passes that rearrange functions.

You could probably write a Module pass that sorted the Functions by source
location; that's the only solution that comes to mind.  You'd need to
define the ordering across files (e.g., the source location of a function
defined in a header; this happens a lot in C++, not so much in C).
--paulr

> 
> That said, clang doesn't really try to emit functions in source order:
> it will delay emitting functions for various reasons.  If that's truly
> necessary for your use-case, you'll probably have to modify clang
> somehow.  Or maybe -femit-all-decls is close enough if your input is pure
> C?
> 
> -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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