[llvm] 0b3e393 - [TableGen] [CodeGenTarget] Cache the target's instruction namespace.

[Paul C. Anagnostopoulos via llvm-commits]

Author: Paul C. Anagnostopoulos
Date: 2020-12-06T11:08:30-05:00
New Revision: 0b3e393d6c8b0f6bb8a13b1a71aba796c87ed239

URL: https://github.com/llvm/llvm-project/commit/0b3e393d6c8b0f6bb8a13b1a71aba796c87ed239
DIFF: https://github.com/llvm/llvm-project/commit/0b3e393d6c8b0f6bb8a13b1a71aba796c87ed239.diff

LOG: [TableGen] [CodeGenTarget] Cache the target's instruction namespace.

Differential Revision: https://reviews.llvm.org/D92722

Added: 
    

Modified: 
    llvm/utils/TableGen/CodeGenTarget.cpp
    llvm/utils/TableGen/CodeGenTarget.h

Removed: 
    


################################################################################
diff  --git a/llvm/utils/TableGen/CodeGenTarget.cpp b/llvm/utils/TableGen/CodeGenTarget.cpp
index 794bb622dc99..d8e1d7f8cf0d 100644
--- a/llvm/utils/TableGen/CodeGenTarget.cpp
+++ b/llvm/utils/TableGen/CodeGenTarget.cpp
@@ -264,15 +264,20 @@ const StringRef CodeGenTarget::getName() const {
   return TargetRec->getName();
 }
 
+/// getInstNamespace - Find and return the target machine's instruction
+/// namespace. The namespace is cached because it is requested multiple times.
 StringRef CodeGenTarget::getInstNamespace() const {
-  for (const CodeGenInstruction *Inst : getInstructionsByEnumValue()) {
-    // Make sure not to pick up "TargetOpcode" by accidentally getting
-    // the namespace off the PHI instruction or something.
-    if (Inst->Namespace != "TargetOpcode")
-      return Inst->Namespace;
+  if (InstNamespace.empty()) {
+    for (const CodeGenInstruction *Inst : getInstructionsByEnumValue()) {
+      // We are not interested in the "TargetOpcode" namespace.
+      if (Inst->Namespace != "TargetOpcode") {
+        InstNamespace = Inst->Namespace;
+        break;
+      }
+    }
   }
 
-  return "";
+  return InstNamespace;
 }
 
 StringRef CodeGenTarget::getRegNamespace() const {

diff  --git a/llvm/utils/TableGen/CodeGenTarget.h b/llvm/utils/TableGen/CodeGenTarget.h
index 44bc46a0a421..cc5bbe7a8bfe 100644
--- a/llvm/utils/TableGen/CodeGenTarget.h
+++ b/llvm/utils/TableGen/CodeGenTarget.h
@@ -60,6 +60,7 @@ class CodeGenTarget {
 
   mutable std::unique_ptr<CodeGenSchedModels> SchedModels;
 
+  mutable StringRef InstNamespace;
   mutable std::vector<const CodeGenInstruction*> InstrsByEnum;
   mutable unsigned NumPseudoInstructions = 0;
 public: