[llvm] r335378 - AMDHSA: Put old assembler docs back
Konstantin Zhuravlyov via llvm-commits
llvm-commits at lists.llvm.org
Fri Jun 22 12:23:18 PDT 2018
Author: kzhuravl
Date: Fri Jun 22 12:23:18 2018
New Revision: 335378
URL: http://llvm.org/viewvc/llvm-project?rev=335378&view=rev
Log:
AMDHSA: Put old assembler docs back
Until we switch to code object v3 by default.
Follow up for https://reviews.llvm.org/D47736.
Differential Revision: https://reviews.llvm.org/D48497
Modified:
llvm/trunk/docs/AMDGPUUsage.rst
Modified: llvm/trunk/docs/AMDGPUUsage.rst
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/AMDGPUUsage.rst?rev=335378&r1=335377&r2=335378&view=diff
==============================================================================
--- llvm/trunk/docs/AMDGPUUsage.rst (original)
+++ llvm/trunk/docs/AMDGPUUsage.rst Fri Jun 22 12:23:18 2018
@@ -4303,8 +4303,103 @@ VOP_SDWA examples:
For full list of supported instructions, refer to "Vector ALU instructions".
-Predefined Symbols
-~~~~~~~~~~~~~~~~~~
+.. TODO
+ Remove once we switch to code object v3 by default.
+
+HSA Code Object Directives
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+AMDGPU ABI defines auxiliary data in output code object. In assembly source,
+one can specify them with assembler directives.
+
+.hsa_code_object_version major, minor
++++++++++++++++++++++++++++++++++++++
+
+*major* and *minor* are integers that specify the version of the HSA code
+object that will be generated by the assembler.
+
+.hsa_code_object_isa [major, minor, stepping, vendor, arch]
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+
+
+*major*, *minor*, and *stepping* are all integers that describe the instruction
+set architecture (ISA) version of the assembly program.
+
+*vendor* and *arch* are quoted strings. *vendor* should always be equal to
+"AMD" and *arch* should always be equal to "AMDGPU".
+
+By default, the assembler will derive the ISA version, *vendor*, and *arch*
+from the value of the -mcpu option that is passed to the assembler.
+
+.amdgpu_hsa_kernel (name)
++++++++++++++++++++++++++
+
+This directives specifies that the symbol with given name is a kernel entry point
+(label) and the object should contain corresponding symbol of type STT_AMDGPU_HSA_KERNEL.
+
+.amd_kernel_code_t
+++++++++++++++++++
+
+This directive marks the beginning of a list of key / value pairs that are used
+to specify the amd_kernel_code_t object that will be emitted by the assembler.
+The list must be terminated by the *.end_amd_kernel_code_t* directive. For
+any amd_kernel_code_t values that are unspecified a default value will be
+used. The default value for all keys is 0, with the following exceptions:
+
+- *kernel_code_version_major* defaults to 1.
+- *machine_kind* defaults to 1.
+- *machine_version_major*, *machine_version_minor*, and
+ *machine_version_stepping* are derived from the value of the -mcpu option
+ that is passed to the assembler.
+- *kernel_code_entry_byte_offset* defaults to 256.
+- *wavefront_size* defaults to 6.
+- *kernarg_segment_alignment*, *group_segment_alignment*, and
+ *private_segment_alignment* default to 4. Note that alignments are specified
+ as a power of two, so a value of **n** means an alignment of 2^ **n**.
+
+The *.amd_kernel_code_t* directive must be placed immediately after the
+function label and before any instructions.
+
+For a full list of amd_kernel_code_t keys, refer to AMDGPU ABI document,
+comments in lib/Target/AMDGPU/AmdKernelCodeT.h and test/CodeGen/AMDGPU/hsa.s.
+
+Here is an example of a minimal amd_kernel_code_t specification:
+
+.. code-block:: none
+
+ .hsa_code_object_version 1,0
+ .hsa_code_object_isa
+
+ .hsatext
+ .globl hello_world
+ .p2align 8
+ .amdgpu_hsa_kernel hello_world
+
+ hello_world:
+
+ .amd_kernel_code_t
+ enable_sgpr_kernarg_segment_ptr = 1
+ is_ptr64 = 1
+ compute_pgm_rsrc1_vgprs = 0
+ compute_pgm_rsrc1_sgprs = 0
+ compute_pgm_rsrc2_user_sgpr = 2
+ kernarg_segment_byte_size = 8
+ wavefront_sgpr_count = 2
+ workitem_vgpr_count = 3
+ .end_amd_kernel_code_t
+
+ s_load_dwordx2 s[0:1], s[0:1] 0x0
+ v_mov_b32 v0, 3.14159
+ s_waitcnt lgkmcnt(0)
+ v_mov_b32 v1, s0
+ v_mov_b32 v2, s1
+ flat_store_dword v[1:2], v0
+ s_endpgm
+ .Lfunc_end0:
+ .size hello_world, .Lfunc_end0-hello_world
+
+Predefined Symbols (-mattr=+code-object-v3)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The AMDGPU assembler defines and updates some symbols automatically. These
symbols do not affect code generation.
@@ -4343,8 +4438,8 @@ May be used to set the `.amdhsa_next_fre
May be set at any time, e.g. manually set to zero at the start of each kernel.
-Code Object Directives
-~~~~~~~~~~~~~~~~~~~~~~
+Code Object Directives (-mattr=+code-object-v3)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Directives which begin with ``.amdgcn`` are valid for all ``amdgcn``
architecture processors, and are not OS-specific. Directives which begin with
@@ -4473,8 +4568,8 @@ terminated by an ``.end_amdhsa_kernel``
:ref:`amdgpu-amdhsa-compute_pgm_rsrc2-gfx6-gfx9-table`.
======================================================== ================ ============ ===================
-Example HSA Source Code
-~~~~~~~~~~~~~~~~~~~~~~~
+Example HSA Source Code (-mattr=+code-object-v3)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Here is an example of a minimal assembly source file, defining one HSA kernel:
More information about the llvm-commits
mailing list