[AMDGPU] Convert AMDGPUResourceUsageAnalysis pass from Module to MF p…

…ass (llvm#102913)

Converts AMDGPUResourceUsageAnalysis pass from Module to MachineFunction
pass. Moves function resource info propagation to to MC layer (through
helpers in AMDGPUMCResourceInfo) by generating MCExprs for every
function resource which the emitters have been prepped for.

Fixes llvm#64863

clang/test/Frontend/amdgcn-machine-analysis-remarks.cl

@@ -2,7 +2,7 @@
 // RUN: %clang_cc1 -triple amdgcn-amd-amdhsa -target-cpu gfx908 -Rpass-analysis=kernel-resource-usage -S -O0 -verify %s -o /dev/null
 
 // expected-remark@+10 {{Function Name: foo}}
-// expected-remark@+9 {{ SGPRs: 13}}
+// expected-remark@+9 {{ TotalSGPRs: 13}}
 // expected-remark@+8 {{ VGPRs: 10}}
 // expected-remark@+7 {{ AGPRs: 12}}
 // expected-remark@+6 {{ ScratchSize [bytes/lane]: 0}}

llvm/docs/AMDGPUUsage.rst

@@ -1757,6 +1757,55 @@ As part of the AMDGPU MC layer, AMDGPU provides the following target specific
 
  =================== ================= ========================================================
 
+Function Resource Usage
+-----------------------
+
+A function's resource usage depends on each of its callees' resource usage. The
+expressions used to denote resource usage reflect this by propagating each
+callees' equivalent expressions. Said expressions are emitted as symbols by the
+compiler when compiling to either assembly or object format and should not be
+overwritten or redefined.
+
+The following describes all emitted function resource usage symbols:
+
+ .. table:: Function Resource Usage:
+ :name: function-usage-table
+
+ ===================================== ========= ========================================= ===============================================================================
+ Symbol Type Description Example
+ ===================================== ========= ========================================= ===============================================================================
+ <function_name>.num_vgpr Integer Number of VGPRs used by <function_name>, .set foo.num_vgpr, max(32, bar.num_vgpr, baz.num_vgpr)
+ worst case of itself and its callees'
+ VGPR use
+ <function_name>.num_agpr Integer Number of AGPRs used by <function_name>, .set foo.num_agpr, max(35, bar.num_agpr)
+ worst case of itself and its callees'
+ AGPR use
+ <function_name>.numbered_sgpr Integer Number of SGPRs used by <function_name>, .set foo.num_sgpr, 21
+ worst case of itself and its callees'
+ SGPR use (without any of the implicitly
+ used SGPRs)
+ <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)
+ <function_name>, expression is the
+ locally used stack size + the worst case
+ callee
+ <function_name>.uses_vcc Bool Whether <function_name>, or any of its .set foo.uses_vcc, or(0, bar.uses_vcc)
+ callees, uses vcc
+ <function_name>.uses_flat_scratch Bool Whether <function_name>, or any of its .set foo.uses_flat_scratch, 1
+ callees, uses flat scratch or not
+ <function_name>.has_dyn_sized_stack Bool Whether <function_name>, or any of its .set foo.has_dyn_sized_stack, 1
+ callees, is dynamically sized
+ <function_name>.has_recursion Bool Whether <function_name>, or any of its .set foo.has_recursion, 0
+ callees, contains recursion
+ <function_name>.has_indirect_call Bool Whether <function_name>, or any of its .set foo.has_indirect_call, max(0, bar.has_indirect_call)
+ callees, contains an indirect call
+ ===================================== ========= ========================================= ===============================================================================
+
+Futhermore, three symbols are additionally emitted describing the compilation
+unit's worst case (i.e, maxima) ``num_vgpr``, ``num_agpr``, and
+``numbered_sgpr`` which may be referenced and used by the aforementioned
+symbolic expressions. These three symbols are ``amdgcn.max_num_vgpr``,
+``amdgcn.max_num_agpr``, and ``amdgcn.max_num_sgpr``.
+
 .. _amdgpu-elf-code-object:
 
 ELF Code Object