[mlir][capi] Add NameLoc

[jpienaar]

Summary

Add method to get NameLoc. Treat null child location as unknown to avoid
needing to create UnknownLoc in C API where child loc is not needed.

[ftynse]

mlir/include/mlir-c/IR.h

165

Nit: could you describe the null childLoc behavior here?

mlir/include/mlir-c/IR.h

 /// Creates an File/Line/Column location owned by the given context.
 MLIR_CAPI_EXPORTED MlirLocation mlirLocationFileLineColGet(
     MlirContext context, MlirStringRef filename, unsigned line, unsigned col);
 
 /// Creates a call site location with a callee and a caller.
 MLIR_CAPI_EXPORTED MlirLocation mlirLocationCallSiteGet(MlirLocation callee,
                                                         MlirLocation caller);
 
+/// Creates a name location owned by the given context. Providing null location
+/// for childLoc is allowed and if childLoc is null location, then the behavior
+/// is the same as having unknown child location.
+MLIR_CAPI_EXPORTED MlirLocation mlirLocationNameGet(MlirContext context,
+                                                    MlirStringRef name,
+                                                    MlirLocation childLoc);
+
 /// Creates a location with unknown position owned by the given context.
 MLIR_CAPI_EXPORTED MlirLocation mlirLocationUnknownGet(MlirContext context);
 
 /// Gets the context that a location was created with.
 MLIR_CAPI_EXPORTED MlirContext mlirLocationGetContext(MlirLocation location);
 
 /// Checks if the location is null.
 static inline bool mlirLocationIsNull(MlirLocation location) {

mlir/lib/CAPI/IR/IR.cpp

 #include "mlir-c/Support.h"
 
 #include "mlir/CAPI/IR.h"
 #include "mlir/CAPI/Support.h"
 #include "mlir/CAPI/Utils.h"
 #include "mlir/IR/Attributes.h"
 #include "mlir/IR/BuiltinOps.h"
 #include "mlir/IR/Dialect.h"
+#include "mlir/IR/Location.h"
 #include "mlir/IR/Operation.h"
 #include "mlir/IR/Types.h"
 #include "mlir/IR/Verifier.h"
 #include "mlir/Interfaces/InferTypeOpInterface.h"
 #include "mlir/Parser.h"
 
 #include "llvm/Support/Debug.h"
 
MlirLocation mlirLocationFileLineColGet(MlirContext context,
   return wrap(Location(
       FileLineColLoc::get(unwrap(context), unwrap(filename), line, col)));
 }
 
 MlirLocation mlirLocationCallSiteGet(MlirLocation callee, MlirLocation caller) {
   return wrap(Location(CallSiteLoc::get(unwrap(callee), unwrap(caller))));
 }
 
+MlirLocation mlirLocationNameGet(MlirContext context, MlirStringRef name,
+                                 MlirLocation childLoc) {
+  if (mlirLocationIsNull(childLoc))
+    return wrap(
+        Location(NameLoc::get(Identifier::get(unwrap(name), unwrap(context)))));
+  return wrap(Location(NameLoc::get(
+      Identifier::get(unwrap(name), unwrap(context)), unwrap(childLoc))));
+}
+
 MlirLocation mlirLocationUnknownGet(MlirContext context) {
   return wrap(Location(UnknownLoc::get(unwrap(context))));
 }
 
 bool mlirLocationEqual(MlirLocation l1, MlirLocation l2) {
   return unwrap(l1) == unwrap(l2);
 }
 

mlir/test/CAPI/ir.c

 #include "mlir-c/AffineExpr.h"
 #include "mlir-c/AffineMap.h"
 #include "mlir-c/BuiltinAttributes.h"
 #include "mlir-c/BuiltinTypes.h"
 #include "mlir-c/Diagnostics.h"
 #include "mlir-c/Dialect/Standard.h"
 #include "mlir-c/IntegerSet.h"
 #include "mlir-c/Registration.h"
+#include "mlir-c/Support.h"
 
 #include <assert.h>
 #include <inttypes.h>
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
void testDiagnostics() {
   MlirLocation fileLineColLoc = mlirLocationFileLineColGet(
       ctx, mlirStringRefCreateFromCString("file.c"), 1, 2);
   mlirEmitError(fileLineColLoc, "test diagnostics");
   MlirLocation callSiteLoc = mlirLocationCallSiteGet(
       mlirLocationFileLineColGet(
           ctx, mlirStringRefCreateFromCString("other-file.c"), 2, 3),
       fileLineColLoc);
   mlirEmitError(callSiteLoc, "test diagnostics");
+  MlirLocation null = {0};
+  MlirLocation nameLoc =
+      mlirLocationNameGet(ctx, mlirStringRefCreateFromCString("named"), null);
+  mlirEmitError(nameLoc, "test diagnostics");
   mlirContextDetachDiagnosticHandler(ctx, id);
   mlirEmitError(unknownLoc, "more test diagnostics");
   // CHECK-LABEL: @test_diagnostics
   // CHECK: processing diagnostic (userData: 42) <<
   // CHECK:   test diagnostics
   // CHECK:   loc(unknown)
   // CHECK: >> end of diagnostic (userData: 42)
   // CHECK: processing diagnostic (userData: 42) <<
   // CHECK:   test diagnostics
   // CHECK:   loc("file.c":1:2)
   // CHECK: >> end of diagnostic (userData: 42)
   // CHECK: processing diagnostic (userData: 42) <<
   // CHECK:   test diagnostics
   // CHECK:   loc(callsite("other-file.c":2:3 at "file.c":1:2))
   // CHECK: >> end of diagnostic (userData: 42)
+  // CHECK: processing diagnostic (userData: 42) <<
+  // CHECK:   test diagnostics
+  // CHECK:   loc("named")
+  // CHECK: >> end of diagnostic (userData: 42)
   // CHECK: deleting user data (userData: 42)
   // CHECK-NOT: processing diagnostic
   // CHECK:     more test diagnostics
 }
 
 int main() {
   MlirContext ctx = mlirContextCreate();
   mlirRegisterAllDialects(ctx);