[llvm] AMDGPU: AsmParser boilerplate for missing features (PR #157013)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm created https://github.com/llvm/llvm-project/pull/157013

The management of subtarget dependent assembler errors
is currently ignoring the reported issues from MatchInstructionImpl.
Move code around to try making use of it.

>From 07907a1fee9e378e0829f5c11ab2dcf89c3232da Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Fri, 5 Sep 2025 10:18:08 +0900
Subject: [PATCH] AMDGPU: AsmParser boilerplate for missing features

The management of subtarget dependent assembler errors
is currently ignoring the reported issues from MatchInstructionImpl.
Move code around to try making use of it.
---
 .../Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp  | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp b/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp
index fc46f2b6e93dd..522aae08d7353 100644
--- a/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp
+++ b/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp
@@ -1391,6 +1391,7 @@ class AMDGPUAsmParser : public MCTargetAsmParser {
 
 #define GET_ASSEMBLER_HEADER
 #include "AMDGPUGenAsmMatcher.inc"
+#undef GET_ASSEMBLER_HEADER
 
   /// }
 
@@ -2023,6 +2024,12 @@ class AMDGPUAsmParser : public MCTargetAsmParser {
   ParseStatus parseVOPD(OperandVector &Operands);
 };
 
+// TODO: define GET_SUBTARGET_FEATURE_NAME
+#define GET_REGISTER_MATCHER
+#include "AMDGPUGenAsmMatcher.inc"
+#undef GET_REGISTER_MATCHER
+#undef GET_SUBTARGET_FEATURE_NAME
+
 } // end anonymous namespace
 
 // May be called with integer type with equivalent bitwidth.
@@ -5838,10 +5845,14 @@ bool AMDGPUAsmParser::matchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
   MCInst Inst;
   Inst.setLoc(IDLoc);
   unsigned Result = Match_Success;
+  FeatureBitset MissingFeatures;
+
   for (auto Variant : getMatchedVariants()) {
     uint64_t EI;
-    auto R = MatchInstructionImpl(Operands, Inst, EI, MatchingInlineAsm,
-                                  Variant);
+    auto R = MatchInstructionImpl(Operands, Inst, EI, MissingFeatures,
+                                  MatchingInlineAsm, Variant);
+
+    // TODO: Emit diagnostic from MissingFeatures.
     // We order match statuses from least to most specific. We use most specific
     // status as resulting
     // Match_MnemonicFail < Match_InvalidOperand < Match_MissingFeature
@@ -10497,7 +10508,6 @@ LLVMInitializeAMDGPUAsmParser() {
   RegisterMCAsmParser<AMDGPUAsmParser> B(getTheGCNTarget());
 }
 
-#define GET_REGISTER_MATCHER
 #define GET_MATCHER_IMPLEMENTATION
 #define GET_MNEMONIC_SPELL_CHECKER
 #define GET_MNEMONIC_CHECKER