[Mlir-commits] [mlir] 32134a6 - [mlirbc] Switch generator to enable write's with failures. (#182464)

[llvmlistbot at llvm.org]

Author: Jacques Pienaar
Date: 2026-02-27T07:10:49+02:00
New Revision: 32134a64b195f7804698418b6f416e761d890dea

URL: https://github.com/llvm/llvm-project/commit/32134a64b195f7804698418b6f416e761d890dea
DIFF: https://github.com/llvm/llvm-project/commit/32134a64b195f7804698418b6f416e761d890dea.diff

LOG: [mlirbc] Switch generator to enable write's with failures. (#182464)

Previously one had to have a matching case per entry (e.g., one could
use a printer predicate, but the assumption was one woujld never
fallback) and just always return success.

Added: 
    mlir/test/mlir-tblgen/bytecode-write.td

Modified: 
    mlir/lib/Dialect/LLVMIR/IR/LLVMDialectBytecode.cpp
    mlir/tools/mlir-tblgen/BytecodeDialectGen.cpp

Removed: 
    


################################################################################
diff  --git a/mlir/lib/Dialect/LLVMIR/IR/LLVMDialectBytecode.cpp b/mlir/lib/Dialect/LLVMIR/IR/LLVMDialectBytecode.cpp
index 41d1f80580cf7..597690e7c77a2 100644
--- a/mlir/lib/Dialect/LLVMIR/IR/LLVMDialectBytecode.cpp
+++ b/mlir/lib/Dialect/LLVMIR/IR/LLVMDialectBytecode.cpp
@@ -22,13 +22,6 @@ using namespace mlir::LLVM;
 
 namespace {
 
-// Provide some forward declarations of the functions that will be generated by
-// the include below.
-static void write(DIExpressionElemAttr attribute,
-                  DialectBytecodeWriter &writer);
-static LogicalResult writeAttribute(Attribute attribute,
-                                    DialectBytecodeWriter &writer);
-
 //===--------------------------------------------------------------------===//
 // Optional ArrayRefs
 //

diff  --git a/mlir/test/mlir-tblgen/bytecode-write.td b/mlir/test/mlir-tblgen/bytecode-write.td
new file mode 100644
index 0000000000000..ab5a3eea0f0f1
--- /dev/null
+++ b/mlir/test/mlir-tblgen/bytecode-write.td
@@ -0,0 +1,28 @@
+// RUN: mlir-tblgen -gen-bytecode -bytecode-dialect=Test -I %S/../../include %s 2>&1 | FileCheck %s
+
+// Test to show fall through behavior.
+
+include "mlir/IR/BytecodeBase.td"
+
+def Float64Type : DialectType<(type)> {
+  let printerPredicate = "false";
+}
+
+def TestDialectTypes : DialectTypes<"Test"> {
+  let elems = [
+      ReservedOrDead,
+      Float64Type
+  ];
+}
+
+// CHECK-LABEL: static LogicalResult write(Float64Type type, DialectBytecodeWriter &writer) {
+// CHECK:         if (false) {
+// CHECK:           writer.writeVarInt(/* Float64Type */ 1);
+// CHECK:           return success();
+// CHECK:         }
+// CHECK:         return failure();
+// CHECK-LABEL: static LogicalResult writeType(Type type,
+// CHECK:         return TypeSwitch<Type, LogicalResult>(type)
+// CHECK-NEXT:       .Case([&](Float64Type t) {
+// CHECK-NEXT:         return write(t, writer);
+

diff  --git a/mlir/tools/mlir-tblgen/BytecodeDialectGen.cpp b/mlir/tools/mlir-tblgen/BytecodeDialectGen.cpp
index a759ad4d68197..d8004a663aaee 100644
--- a/mlir/tools/mlir-tblgen/BytecodeDialectGen.cpp
+++ b/mlir/tools/mlir-tblgen/BytecodeDialectGen.cpp
@@ -301,7 +301,7 @@ void Generator::emitPrint(StringRef kind, StringRef type,
     return;
 
   char const *head =
-      R"(static void write({0} {1}, DialectBytecodeWriter &writer) )";
+      R"(static LogicalResult write({0} {1}, DialectBytecodeWriter &writer) )";
   mlir::raw_indented_ostream os(output);
   os << formatv(head, type, kind);
   auto funScope = os.scope("{\n", "}\n\n");
@@ -315,7 +315,7 @@ void Generator::emitPrint(StringRef kind, StringRef type,
         StringRef pred = rec->getValueAsString("printerPredicate");
         if (vec.size() > 1 && pred.empty())
           PrintError(rec->getLoc(),
-                     "Requires parsing predicate given common cType");
+                     "Requires printing predicate given common cType");
       }
       PrintFatalError("Unspecified for shared cType " + type);
     }
@@ -341,10 +341,14 @@ void Generator::emitPrint(StringRef kind, StringRef type,
     }
 
     if (!pred.empty()) {
+      os << "return success();\n";
       os.unindent();
       os << "}\n";
+    } else {
+      os << "return success();\n";
     }
   }
+  os << "return failure();\n";
 }
 
 void Generator::emitPrintHelper(const Record *memberRec, StringRef kind,
@@ -418,7 +422,7 @@ void Generator::emitPrintDispatch(StringRef kind, ArrayRef<std::string> vec) {
 
     os << "\n.Case([&](" << type << " t)";
     auto caseScope = os.scope(" {\n", "})");
-    os << "return write(t, writer), success();\n";
+    os << "return write(t, writer);\n";
   }
   os << "\n.Default([&](" << capitalize(kind) << ") { return failure(); });\n";
 }
@@ -475,9 +479,8 @@ static bool emitBCRW(const RecordKeeper &records, raw_ostream &os) {
     gen.emitParseDispatch(kind, *vec);
 
     SmallVector<std::string> types;
-    for (const auto &it : perType) {
+    for (const auto &it : perType)
       types.push_back(it.first);
-    }
     gen.emitPrintDispatch(kind, types);
   }