[llvm] 41f81ad - [Tablegen][NFC] Add a check for duplicate features (#94223)

[via llvm-commits]

Author: Tomas Matheson
Date: 2024-06-11T17:51:25+01:00
New Revision: 41f81ad73583bfff7c7dc1caeacbbb783d004e9c

URL: https://github.com/llvm/llvm-project/commit/41f81ad73583bfff7c7dc1caeacbbb783d004e9c
DIFF: https://github.com/llvm/llvm-project/commit/41f81ad73583bfff7c7dc1caeacbbb783d004e9c.diff

LOG: [Tablegen][NFC] Add a check for duplicate features (#94223)

We hit this downstream and the only evidence of the mistake was that the
results of `Find` on `SubtargetFeatureKV` were corrupted.

Added: 
    

Modified: 
    llvm/utils/TableGen/SubtargetEmitter.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/utils/TableGen/SubtargetEmitter.cpp b/llvm/utils/TableGen/SubtargetEmitter.cpp
index 323470940fec5..60a0402103ce0 100644
--- a/llvm/utils/TableGen/SubtargetEmitter.cpp
+++ b/llvm/utils/TableGen/SubtargetEmitter.cpp
@@ -32,6 +32,7 @@
 #include <cstdint>
 #include <iterator>
 #include <map>
+#include <set>
 #include <string>
 #include <vector>
 
@@ -255,6 +256,9 @@ unsigned SubtargetEmitter::FeatureKeyValues(
 
   llvm::sort(FeatureList, LessRecordFieldName());
 
+  // Check that there are no duplicate keys
+  std::set<StringRef> UniqueKeys;
+
   // Begin feature table
   OS << "// Sorted (by key) array of values for CPU features.\n"
      << "extern const llvm::SubtargetFeatureKV " << Target
@@ -283,6 +287,10 @@ unsigned SubtargetEmitter::FeatureKeyValues(
 
     OS << " },\n";
     ++NumFeatures;
+
+    if (!UniqueKeys.insert(CommandLineName).second)
+      PrintFatalError("Duplicate key in SubtargetFeatureKV: " +
+                      CommandLineName);
   }
 
   // End feature table