[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