[Mlir-commits] [mlir] [mlir][bytecode] Implements back deployment capability for MLIR dialects (PR #70724)

[Matteo Franciolini]

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@@ -1256,6 +1288,21 @@ void BytecodeWriter::writePropertiesSection(EncodingEmitter &emitter) {
 
 LogicalResult mlir::writeBytecodeToFile(Operation *op, raw_ostream &os,
                                         const BytecodeWriterConfig &config) {
+  // Before creating the bytecode writer, give an opportunity to each of the
+  // dialects that registered a target version emission to perform IR
+  // downgrades. Note that it is responsibility of client dialect to handle the
+  // potentially destructive changes that a downgrade function could do to the
+  // IR.
+  for (auto &item : config.getDialectVersionMap()) {
+    Dialect *currentDialect = op->getContext()->getOrLoadDialect(item.getKey());
+    assert(currentDialect &&
+           "version requested on a dialect that could not be loaded");
+    auto *iface = llvm::dyn_cast<BytecodeDialectInterface>(currentDialect);
+    assert(iface && "version requested on a dialect that did not implement a "
+                    "`BytecodeDialectInterface`");
+    if (failed(iface->downgradeToVersion(op, *item.getValue())))
+      return failure();
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mfrancio wrote:

Thanks for the feedback. I removed the functionality associated to downgrading constructs, which is now left to the client entirely, and added an example of downgrade as part of the tests. I also modified title and description accordingly.

https://github.com/llvm/llvm-project/pull/70724