[AMDGPU] Convert AMDGPUResourceUsageAnalysis pass from Module to MF pass (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

[AMDGPU] Fix stack size metadata for functions with direct and indirect calls (llvm#110828)

When a function has an external call, it should still use the stack
sizes of direct, known, calls to calculate its own stack size

[AMDGPU] Fix resource usage information for unnamed functions (llvm#115320)

Resource usage information would try to overwrite unnamed functions if
there are multiple within the same compilation unit. This aims to either
use the `MCSymbol` assigned to the unnamed function (i.e.,
`CurrentFnSym`), or, rematerialize the `MCSymbol` for the unnamed
function.

Reapply [AMDGPU] Avoid resource propagation for recursion through multiple functions (llvm#112251)

I was wrong last patch. I viewed the `Visited` set purely as a possible
recursion deterrent where functions calling a callee multiple times are
handled elsewhere. This doesn't consider cases where a function is
called multiple times by different callers still part of the same call
graph. New test shows the aforementioned case.

Reapplies llvm#111004, fixes llvm#115562.

[AMDGPU] Newly added test modified for recent SGPR use change (llvm#116427)

Mistimed rebase for llvm#112251 which added new tests which did not consider
the changes introduced in llvm#112403 yet

Change-Id: I4dfe6a1b679137e080a6d2b44016347ea704b014

Author: JanekvO

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

@@ -1818,6 +1818,55 @@ 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