[cfe-dev] builtins name mangling in SPIR 2.0

Hongbin Zheng via cfe-dev cfe-dev at lists.llvm.org
Fri Sep 16 21:32:54 PDT 2016


On Fri, Sep 16, 2016 at 8:10 AM, Liu, Yaxun (Sam) <Yaxun.Liu at amd.com> wrote:

> + Alexey Anastasia
>
>
>
> According to SPIR spec v1.2 s2.10.3
>
>
>
> *2.10.3 The printf function*
> The printf function is supported, and is mangled according to its
> prototype as follows:
> int printf(constant char * restrict fmt, ... )
>
clang 3.9 will drop the 'restrict' when it mangle this name, or I am
missing some commandline argument?

Thanks
Hongbin


> Note that the ellipsis formal argument (...) is mangled to argument type
> specifier z
>
>
>
> It seems printf should be mangled.
>
>
>
> Alexey/Anastasia,
>
>
>
> What do you think? Thanks.
>
>
>
> Sam
>
>
>
> *From:* Hongbin Zheng [mailto:etherzhhb at gmail.com]
> *Sent:* Friday, September 16, 2016 1:54 AM
> *To:* Liu, Yaxun (Sam) <Yaxun.Liu at amd.com>
> *Cc:* cfe-dev at lists.llvm.org; llvm-dev <llvm-dev at lists.llvm.org>
> *Subject:* Re: builtins name mangling in SPIR 2.0
>
>
>
> Hi Sam and others,
>
>
>
> I saw that in [1], printf is mangled to _Z6printfPrU3AS2cz, while in
> clang's opencl-c.h[2], printf does not have the overload attribute:
>
> int printf(__constant const char* st, ...); (and it is different from the
> standard, which is printf(restrict __constant char *, ...))
>
> I try the following code:
>
> #include <opencl-c.h>
>
>
>
> __kernel void vadd(__global const int* a, __global const int* b, __global
> int* c) {
>
>   printf("aaaaa");
>
> }
>
>
>
> and get a printf that is not mangled:
>
>   %call = tail call spir_func i32 (i8 addrspace(2)*, ...) @printf(i8
> addrspace(2)* getelementptr inbounds ([6 x i8], [6 x i8] addrspace(2)*
> @.str, i64 0, i64 0))
>
>
>
> with the following command line:
>
> clang -cc1 -internal-isystem /wrk/xsjhdnobkup2/hongbinz/
> omp/build-llvm/bin/../lib/clang/3.9.0/include -nostdsysteminc -S
> -emit-llvm -o -
>
>
>
> Is this the correct behavior?
>
>
>
> Thanks
>
> Hongbin
>
>
>
> [1] https://github.com/KhronosGroup/SPIR-Tools/wiki/
> SPIR-2.0-built-in-functions
>
> [2] http://clang.llvm.org/doxygen/opencl-c_8h_source.html
>
>
>
> On Mon, Sep 12, 2016 at 1:43 PM, Hongbin Zheng <etherzhhb at gmail.com>
> wrote:
>
> Thanks a lot.
>
>
>
> On Mon, Sep 12, 2016 at 1:42 PM, Liu, Yaxun (Sam) <Yaxun.Liu at amd.com>
> wrote:
>
> If you use the default header file under clang/lib/Headers/opencl-c.h,
> get_global_id will be mangled.
>
>
>
> If you want to declare get_global_id in your own header, add
> __attribute__((overloadable)), then it will be mangled.
>
>
>
> Sam
>
>
>
> *From:* Hongbin Zheng [mailto:etherzhhb at gmail.com]
> *Sent:* Monday, September 12, 2016 4:21 PM
> *To:* cfe-dev at lists.llvm.org; llvm-dev <llvm-dev at lists.llvm.org>; Liu,
> Yaxun (Sam) <Yaxun.Liu at amd.com>
> *Subject:* builtins name mangling in SPIR 2.0
>
>
>
> Hi all,
>
>
>
> According to the SPIR 2.0 spec[1], the name of OpenCL builtins are mangled.
>
>
>
> However, when I compile OpenCl code with Clang 3.9 with the
> "spir64-unknown-unknown" target, Clang generates IR without mangling the
> builtins, e.g. for:
>
>
>
> __kernel void input_zip_int(__global int *in0) {
>
>   *in0 = get_global_id(0);
>
> }
>
>
>
> clang generates:
>
>
>
> define spir_kernel void @input_zip_int(i32 addrspace(1)* nocapture %in0)
> local_unnamed_addr #0 !kernel_arg_addr_space !3 !kernel_arg_access_qual !4
> !kernel_arg_type !5 !kernel_arg_base_type !5 !kernel_arg_type_qual !6 {
>
> entry:
>
>   %call = tail call spir_func i128 @get_global_id(i32 0) #2
>
>   %conv = trunc i128 %call to i32
>
>   store i32 %conv, i32 addrspace(1)* %in0, align 4, !tbaa !7
>
>   ret void
>
> }
>
>
>
> In this case, get_global_id is not mangled to _Z13get_global_idj according
> to [2].
>
>
>
> Is there an option for clang or an LLVM clang to do the mangling for spir
> builtins?
>
>
>
> Thanks
>
> Hongbin
>
>
>
>
>
> [1] https://www.khronos.org/registry/spir/specs/spir_spec-2.0.pdf, page 36
>
> [2] https://github.com/KhronosGroup/SPIR-Tools/wiki/
> SPIR-2.0-built-in-functions
>
>
>
>
>
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