[llvm] [LLVM][TableGen] Move DecoderEmitter output to anonymous namespace (PR #136214)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-tablegen

Author: Rahul Joshi (jurahul)

<details>
<summary>Changes</summary>

- Move the code generated by DecoderEmitter to anonymous namespace.
- Move AMDGPU's usage of this code from header file to .cpp file.

Note, we get build errors like "call to function 'decodeInstruction' that is neither visible in the template definition nor found by argument-dependent lookup" if we do not change AMDGPU.

---
Full diff: https://github.com/llvm/llvm-project/pull/136214.diff


3 Files Affected:

- (modified) llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.cpp (+40) 
- (modified) llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.h (+2-32) 
- (modified) llvm/utils/TableGen/DecoderEmitter.cpp (+2-2) 


``````````diff
diff --git a/llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.cpp b/llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.cpp
index 847121f251361..3fbba17159375 100644
--- a/llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.cpp
+++ b/llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.cpp
@@ -487,6 +487,46 @@ static DecodeStatus decodeVersionImm(MCInst &Inst, unsigned Imm,
 //
 //===----------------------------------------------------------------------===//
 
+template <typename InsnType>
+DecodeStatus AMDGPUDisassembler::tryDecodeInst(const uint8_t *Table, MCInst &MI,
+                                               InsnType Inst, uint64_t Address,
+                                               raw_ostream &Comments) const {
+  assert(MI.getOpcode() == 0);
+  assert(MI.getNumOperands() == 0);
+  MCInst TmpInst;
+  HasLiteral = false;
+  const auto SavedBytes = Bytes;
+
+  SmallString<64> LocalComments;
+  raw_svector_ostream LocalCommentStream(LocalComments);
+  CommentStream = &LocalCommentStream;
+
+  DecodeStatus Res =
+      decodeInstruction(Table, TmpInst, Inst, Address, this, STI);
+
+  CommentStream = nullptr;
+
+  if (Res != MCDisassembler::Fail) {
+    MI = TmpInst;
+    Comments << LocalComments;
+    return MCDisassembler::Success;
+  }
+  Bytes = SavedBytes;
+  return MCDisassembler::Fail;
+}
+
+template <typename InsnType>
+DecodeStatus
+AMDGPUDisassembler::tryDecodeInst(const uint8_t *Table1, const uint8_t *Table2,
+                                  MCInst &MI, InsnType Inst, uint64_t Address,
+                                  raw_ostream &Comments) const {
+  for (const uint8_t *T : {Table1, Table2}) {
+    if (DecodeStatus Res = tryDecodeInst(T, MI, Inst, Address, Comments))
+      return Res;
+  }
+  return MCDisassembler::Fail;
+}
+
 template <typename T> static inline T eatBytes(ArrayRef<uint8_t>& Bytes) {
   assert(Bytes.size() >= sizeof(T));
   const auto Res =
diff --git a/llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.h b/llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.h
index 29452166e21a0..498ef655b7f45 100644
--- a/llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.h
+++ b/llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.h
@@ -130,41 +130,11 @@ class AMDGPUDisassembler : public MCDisassembler {
 
   template <typename InsnType>
   DecodeStatus tryDecodeInst(const uint8_t *Table, MCInst &MI, InsnType Inst,
-                             uint64_t Address, raw_ostream &Comments) const {
-    assert(MI.getOpcode() == 0);
-    assert(MI.getNumOperands() == 0);
-    MCInst TmpInst;
-    HasLiteral = false;
-    const auto SavedBytes = Bytes;
-
-    SmallString<64> LocalComments;
-    raw_svector_ostream LocalCommentStream(LocalComments);
-    CommentStream = &LocalCommentStream;
-
-    DecodeStatus Res =
-        decodeInstruction(Table, TmpInst, Inst, Address, this, STI);
-
-    CommentStream = nullptr;
-
-    if (Res != Fail) {
-      MI = TmpInst;
-      Comments << LocalComments;
-      return MCDisassembler::Success;
-    }
-    Bytes = SavedBytes;
-    return MCDisassembler::Fail;
-  }
-
+                             uint64_t Address, raw_ostream &Comments) const;
   template <typename InsnType>
   DecodeStatus tryDecodeInst(const uint8_t *Table1, const uint8_t *Table2,
                              MCInst &MI, InsnType Inst, uint64_t Address,
-                             raw_ostream &Comments) const {
-    for (const uint8_t *T : {Table1, Table2}) {
-      if (DecodeStatus Res = tryDecodeInst(T, MI, Inst, Address, Comments))
-        return Res;
-    }
-    return MCDisassembler::Fail;
-  }
+                             raw_ostream &Comments) const;
 
   Expected<bool> onSymbolStart(SymbolInfoTy &Symbol, uint64_t &Size,
                                ArrayRef<uint8_t> Bytes,
diff --git a/llvm/utils/TableGen/DecoderEmitter.cpp b/llvm/utils/TableGen/DecoderEmitter.cpp
index 9c6015cc24576..35c928fae7b2b 100644
--- a/llvm/utils/TableGen/DecoderEmitter.cpp
+++ b/llvm/utils/TableGen/DecoderEmitter.cpp
@@ -2417,7 +2417,7 @@ void DecoderEmitter::run(raw_ostream &o) {
 #include "llvm/TargetParser/SubtargetFeature.h"
 #include <assert.h>
 
-namespace llvm {
+namespace {
 )";
 
   emitFieldFromInstruction(OS);
@@ -2561,7 +2561,7 @@ namespace llvm {
   // Emit the main entry point for the decoder, decodeInstruction().
   emitDecodeInstruction(OS, IsVarLenInst);
 
-  OS << "\n} // end namespace llvm\n";
+  OS << "\n} // end anonymous namespace\n";
 }
 
 void llvm::EmitDecoder(const RecordKeeper &RK, raw_ostream &OS,

``````````

</details>


https://github.com/llvm/llvm-project/pull/136214