[mlir] Fix verifier for call debug locations

[clementval]

Summary

D157096 introduces a new verifier for debug location
on call operation. isDeclaration() is actually not defined
for LLVMFuncOp and default to the interface definition that always
return false. This leads to wrong diagnostic in some case as shown in the added test.
Use callee.isExternal() instead that returns the
desired information.

We have seen this error being triggered during flang codegen.

[vzakhari]

Thank you!

[Dinistro]

LGTM!
Sorry for the inconvenience.

[Dinistro]

mlir/test/Dialect/LLVMIR/call-location.mlir

2

NIT: There is no need to forward stderr to stdout here, right?

[clementval]

In D157447#4571807, @Dinistro wrote:

LGTM!
Sorry for the inconvenience.

No worries!

mlir/test/Dialect/LLVMIR/call-location.mlir

2

Thanks. I'll remove it before landing the patch.

mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp

MutableOperandRange CallOp::getArgOperandsMutable() {
   return MutableOperandRange(*this, getCallee().has_value() ? 0 : 1,
                              getCalleeOperands().size());
 }
 
 /// Verify that an inlinable callsite of a debug-info-bearing function in a
 /// debug-info-bearing function has a debug location attached to it. This
 /// mirrors an LLVM IR verifier.
 static LogicalResult verifyCallOpDebugInfo(CallOp callOp, LLVMFuncOp callee) {
-  if (callee.isDeclaration())
+  if (callee.isExternal())
     return success();
   auto parentFunc = callOp->getParentOfType<FunctionOpInterface>();
   if (!parentFunc)
     return success();
 
   auto hasSubprogram = [](Operation *op) {
     return op->getLoc()
                ->findInstanceOf<FusedLocWith<LLVM::DISubprogramAttr>>() !=

mlir/test/Dialect/LLVMIR/call-location.mlir

+// RUN: mlir-opt %s -split-input-file | FileCheck %s
+
+#di_file = #llvm.di_file<"file.cpp" in "/folder/">
+#di_compile_unit = #llvm.di_compile_unit<
+  sourceLanguage = DW_LANG_C_plus_plus_14, file = #di_file,
+  isOptimized = true, emissionKind = Full
+>
+#di_subprogram = #llvm.di_subprogram<
+  compileUnit = #di_compile_unit, scope = #di_file,
+  name = "missing_debug_loc", file = #di_file,
+  subprogramFlags = "Definition|Optimized"
+>
+#di_subprogram1 = #llvm.di_subprogram<
+  compileUnit = #di_compile_unit, scope = #di_file,
+  name = "invalid_call_debug_locs", file = #di_file,
+  subprogramFlags = "Definition|Optimized"
+>
+#loc = loc(unknown)
+#loc1 = loc("file.cpp":24:0)
+#loc2 = loc(fused<#di_subprogram>[#loc1])
+#loc3 = loc("file.cpp":42:0)
+#loc4 = loc(fused<#di_subprogram1>[#loc3])
+
+llvm.func @external_func() loc(#loc2)
+
+llvm.func @call_debug_locs() {
+  llvm.call @external_func() : () -> () loc(#loc)
+  llvm.return
+} loc(#loc4)
+
+// CHECK: llvm.call @external_func()