[Mlir-commits] [mlir] [mlir][spirv] Add gpu printf op lowering to spirv.CL.printf op (PR #78510)

[Jakub Kuderski]

================
@@ -607,6 +616,108 @@ class GPUSubgroupReduceConversion final
   }
 };
 
+LogicalResult GPUPrintfConversion::matchAndRewrite(
+    gpu::PrintfOp gpuPrintfOp, OpAdaptor adaptor,
+    ConversionPatternRewriter &rewriter) const {
+
+  auto loc = gpuPrintfOp.getLoc();
+
+  auto funcOp =
+      rewriter.getBlock()->getParent()->getParentOfType<mlir::spirv::FuncOp>();
+
+  auto moduleOp = funcOp->getParentOfType<mlir::spirv::ModuleOp>();
+
+  const char formatStringPrefix[] = "printfMsg";
+  unsigned stringNumber = 0;
+  mlir::SmallString<16> globalVarName;
+  mlir::spirv::GlobalVariableOp globalVar;
+
+  // formulate spirv global variable name
+  do {
+    globalVarName.clear();
+    (formatStringPrefix + llvm::Twine(stringNumber++))
+        .toStringRef(globalVarName);
+  } while (moduleOp.lookupSymbol(globalVarName));
+
+  auto i8Type = rewriter.getI8Type();
+  auto i32Type = rewriter.getI32Type();
+
+  unsigned scNum = 0;
+  auto createSpecConstant = [&](unsigned value) {
+    auto attr = rewriter.getI8IntegerAttr(value);
+    mlir::SmallString<16> specCstName;
+    (llvm::Twine(globalVarName) + "_sc" + llvm::Twine(scNum++))
+        .toStringRef(specCstName);
+
+    return rewriter.create<mlir::spirv::SpecConstantOp>(
+        loc, rewriter.getStringAttr(specCstName), attr);
+  };
+
+  // define GlobalVarOp with printf format string using SpecConstants
+  // and make composite of SpecConstants
+  {
+    mlir::Operation *parent =
+        mlir::SymbolTable::getNearestSymbolTable(gpuPrintfOp->getParentOp());
+
+    mlir::ConversionPatternRewriter::InsertionGuard guard(rewriter);
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kuhar wrote:

nit: we don't need the mlir namespace prefix

https://github.com/llvm/llvm-project/pull/78510