[mlir] Adds argument attributes for using LLVM's sret and byval attributes

to the conversion of LLVM IR dialect. These attributes are used in FIR to
support the lowering of Fortran using target-specific calling conventions.

Add roundtrip tests.

Add changes per review comments/concerns.

Reviewed By: ftynse

Differential Revision: https://reviews.llvm.org/D94052

diff --git a/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp b/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
index 7700867..492025b 100644 (file)
--- a/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
@@ -1102,6 +1102,22 @@ LogicalResult ModuleTranslation::convertOneFunction(LLVMFuncOp func) {
           llvm::AttrBuilder().addAlignmentAttr(llvm::Align(attr.getInt())));
     }
 
+    if (auto attr = func.getArgAttrOfType<UnitAttr>(argIdx, "llvm.sret")) {
+      auto argTy = mlirArg.getType();
+      if (!argTy.isa<LLVM::LLVMPointerType>())
+        return func.emitError(
+            "llvm.sret attribute attached to LLVM non-pointer argument");
+      llvmArg.addAttr(llvm::Attribute::AttrKind::StructRet);
+    }
+
+    if (auto attr = func.getArgAttrOfType<UnitAttr>(argIdx, "llvm.byval")) {
+      auto argTy = mlirArg.getType();
+      if (!argTy.isa<LLVM::LLVMPointerType>())
+        return func.emitError(
+            "llvm.byval attribute attached to LLVM non-pointer argument");
+      llvmArg.addAttr(llvm::Attribute::AttrKind::ByVal);
+    }
+
     valueMapping[mlirArg] = &llvmArg;
     argIdx++;
   }

diff --git a/mlir/test/Dialect/LLVMIR/func.mlir b/mlir/test/Dialect/LLVMIR/func.mlir
index 72e117d..d9d7e17 100644 (file)
--- a/mlir/test/Dialect/LLVMIR/func.mlir
+++ b/mlir/test/Dialect/LLVMIR/func.mlir
@@ -87,6 +87,16 @@ module {
     llvm.return
   }
 
+  // CHECK: llvm.func @byvalattr(%{{.*}}: !llvm.ptr<i32> {llvm.byval})
+  llvm.func @byvalattr(%arg0: !llvm.ptr<i32> {llvm.byval}) {
+    llvm.return
+  }
+
+  // CHECK: llvm.func @sretattr(%{{.*}}: !llvm.ptr<i32> {llvm.sret})
+  llvm.func @sretattr(%arg0: !llvm.ptr<i32> {llvm.sret}) {
+    llvm.return
+  }
+
   // CHECK: llvm.func @variadic(...)
   llvm.func @variadic(...)
 

diff --git a/mlir/test/Target/llvmir-invalid.mlir b/mlir/test/Target/llvmir-invalid.mlir
index 1411759..fcd98ef 100644 (file)
--- a/mlir/test/Target/llvmir-invalid.mlir
+++ b/mlir/test/Target/llvmir-invalid.mlir
@@ -14,6 +14,19 @@ llvm.func @invalid_noalias(%arg0 : !llvm.float {llvm.noalias = true}) -> !llvm.f
 
 // -----
 
+// expected-error @+1 {{llvm.sret attribute attached to LLVM non-pointer argument}}
+llvm.func @invalid_noalias(%arg0 : !llvm.float {llvm.sret}) -> !llvm.float {
+  llvm.return %arg0 : !llvm.float
+}
+// -----
+
+// expected-error @+1 {{llvm.byval attribute attached to LLVM non-pointer argument}}
+llvm.func @invalid_noalias(%arg0 : !llvm.float {llvm.byval}) -> !llvm.float {
+  llvm.return %arg0 : !llvm.float
+}
+
+// -----
+
 // expected-error @+1 {{llvm.align attribute attached to LLVM non-pointer argument}}
 llvm.func @invalid_align(%arg0 : !llvm.float {llvm.align = 4}) -> !llvm.float {
   llvm.return %arg0 : !llvm.float