@@ -1758,6 +1758,55 @@ As part of the AMDGPU MC layer, AMDGPU provides the following target specific
17581758
17591759 =================== ================= ========================================================
17601760
1761+ Function Resource Usage
1762+ -----------------------
1763+
1764+ A function's resource usage depends on each of its callees' resource usage. The
1765+ expressions used to denote resource usage reflect this by propagating each
1766+ callees' equivalent expressions. Said expressions are emitted as symbols by the
1767+ compiler when compiling to either assembly or object format and should not be
1768+ overwritten or redefined.
1769+
1770+ The following describes all emitted function resource usage symbols:
1771+
1772+ .. table:: Function Resource Usage:
1773+ :name: function-usage-table
1774+
1775+ ===================================== ========= ========================================= ===============================================================================
1776+ Symbol Type Description Example
1777+ ===================================== ========= ========================================= ===============================================================================
1778+ <function_name>.num_vgpr Integer Number of VGPRs used by <function_name>, .set foo.num_vgpr, max(32, bar.num_vgpr, baz.num_vgpr)
1779+ worst case of itself and its callees'
1780+ VGPR use
1781+ <function_name>.num_agpr Integer Number of AGPRs used by <function_name>, .set foo.num_agpr, max(35, bar.num_agpr)
1782+ worst case of itself and its callees'
1783+ AGPR use
1784+ <function_name>.numbered_sgpr Integer Number of SGPRs used by <function_name>, .set foo.num_sgpr, 21
1785+ worst case of itself and its callees'
1786+ SGPR use (without any of the implicitly
1787+ used SGPRs)
1788+ <function_name>.private_seg_size Integer Total stack size required for .set foo.private_seg_size, 16+max(bar.private_seg_size, baz.private_seg_size)
1789+ <function_name>, expression is the
1790+ locally used stack size + the worst case
1791+ callee
1792+ <function_name>.uses_vcc Bool Whether <function_name>, or any of its .set foo.uses_vcc, or(0, bar.uses_vcc)
1793+ callees, uses vcc
1794+ <function_name>.uses_flat_scratch Bool Whether <function_name>, or any of its .set foo.uses_flat_scratch, 1
1795+ callees, uses flat scratch or not
1796+ <function_name>.has_dyn_sized_stack Bool Whether <function_name>, or any of its .set foo.has_dyn_sized_stack, 1
1797+ callees, is dynamically sized
1798+ <function_name>.has_recursion Bool Whether <function_name>, or any of its .set foo.has_recursion, 0
1799+ callees, contains recursion
1800+ <function_name>.has_indirect_call Bool Whether <function_name>, or any of its .set foo.has_indirect_call, max(0, bar.has_indirect_call)
1801+ callees, contains an indirect call
1802+ ===================================== ========= ========================================= ===============================================================================
1803+
1804+ Futhermore, three symbols are additionally emitted describing the compilation
1805+ unit's worst case (i.e, maxima) ``num_vgpr``, ``num_agpr``, and
1806+ ``numbered_sgpr`` which may be referenced and used by the aforementioned
1807+ symbolic expressions. These three symbols are ``amdgcn.max_num_vgpr``,
1808+ ``amdgcn.max_num_agpr``, and ``amdgcn.max_num_sgpr``.
1809+
17611810.. _amdgpu-elf-code-object:
17621811
17631812ELF Code Object
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