[flang] Source code location for IF statements and constructs (#90853)

Make source code locations for IF statements and IF construct component
statements more accurate. Make similar changes to ASSOCIATE, BLOCK, and
SELECT TYPE construct component statements.

Author: vdonaldson

flang/lib/Lower/Bridge.cpp

@@ -2055,17 +2055,19 @@ class FirConverter : public Fortran::lower::AbstractConverter {
   /// Generate structured or unstructured FIR for an IF construct.
   /// The initial statement may be either an IfStmt or an IfThenStmt.
   void genFIR(const Fortran::parser::IfConstruct &) {
-    mlir::Location loc = toLocation();
     Fortran::lower::pft::Evaluation &eval = getEval();
+
+    // Structured fir.if nest.
     if (eval.lowerAsStructured()) {
-      // Structured fir.if nest.
       fir::IfOp topIfOp, currentIfOp;
       for (Fortran::lower::pft::Evaluation &e : eval.getNestedEvaluations()) {
         auto genIfOp = [&](mlir::Value cond) {
-          auto ifOp = builder->create<fir::IfOp>(loc, cond, /*withElse=*/true);
+          auto ifOp =
+              builder->create<fir::IfOp>(toLocation(), cond, /*withElse=*/true);
           builder->setInsertionPointToStart(&ifOp.getThenRegion().front());
           return ifOp;
         };
+        setCurrentPosition(e.position);
         if (auto *s = e.getIf<Fortran::parser::IfThenStmt>()) {
           topIfOp = currentIfOp = genIfOp(genIfCondition(s, e.negateCondition));
         } else if (auto *s = e.getIf<Fortran::parser::IfStmt>()) {
@@ -2096,6 +2098,7 @@ class FirConverter : public Fortran::lower::AbstractConverter {
         else // non-empty block
           genConditionalBranch(cond, e.lexicalSuccessor, e.controlSuccessor);
       };
+      setCurrentPosition(e.position);
       if (auto *s = e.getIf<Fortran::parser::IfThenStmt>()) {
         maybeStartBlock(e.block);
         genIfBranch(genIfCondition(s, e.negateCondition));
@@ -2863,6 +2866,7 @@ class FirConverter : public Fortran::lower::AbstractConverter {
     Fortran::lower::StatementContext stmtCtx;
     pushActiveConstruct(eval, stmtCtx);
     for (Fortran::lower::pft::Evaluation &e : eval.getNestedEvaluations()) {
+      setCurrentPosition(e.position);
       if (auto *stmt = e.getIf<Fortran::parser::AssociateStmt>()) {
         if (eval.lowerAsUnstructured())
           maybeStartBlock(e.block);
@@ -2891,10 +2895,10 @@ class FirConverter : public Fortran::lower::AbstractConverter {
     Fortran::lower::StatementContext stmtCtx;
     pushActiveConstruct(eval, stmtCtx);
     for (Fortran::lower::pft::Evaluation &e : eval.getNestedEvaluations()) {
+      setCurrentPosition(e.position);
       if (e.getIf<Fortran::parser::BlockStmt>()) {
         if (eval.lowerAsUnstructured())
           maybeStartBlock(e.block);
-        setCurrentPosition(e.position);
         const Fortran::parser::CharBlock &endPosition =
             eval.getLastNestedEvaluation().position;
         localSymbols.pushScope();
@@ -2921,7 +2925,6 @@ class FirConverter : public Fortran::lower::AbstractConverter {
       } else if (e.getIf<Fortran::parser::EndBlockStmt>()) {
         if (eval.lowerAsUnstructured())
           maybeStartBlock(e.block);
-        setCurrentPosition(e.position);
         localSymbols.popScope();
       } else {
         genFIR(e);
@@ -2963,7 +2966,6 @@ class FirConverter : public Fortran::lower::AbstractConverter {
   }
 
   void genFIR(const Fortran::parser::SelectTypeConstruct &selectTypeConstruct) {
-    mlir::Location loc = toLocation();
     mlir::MLIRContext *context = builder->getContext();
     Fortran::lower::StatementContext stmtCtx;
     fir::ExtendedValue selector;
@@ -2989,6 +2991,8 @@ class FirConverter : public Fortran::lower::AbstractConverter {
     pushActiveConstruct(getEval(), stmtCtx);
     for (Fortran::lower::pft::Evaluation &eval :
          getEval().getNestedEvaluations()) {
+      setCurrentPosition(eval.position);
+      mlir::Location loc = toLocation();
       if (auto *selectTypeStmt =
               eval.getIf<Fortran::parser::SelectTypeStmt>()) {
         // A genFIR(SelectTypeStmt) call would have unwanted side effects.

flang/test/Lower/if-loc.f90

@@ -0,0 +1,34 @@
+! RUN: bbc -emit-hlfir -mlir-print-debuginfo -o - %s | FileCheck %s
+
+  integer :: n = 0, x = 1
+  if (x .ne. 1) goto 9
+  n = n + 1
+  if (x .gt. 1) goto 9
+  n = n + 1
+9 print *, 'n =', n
+end
+
+! CHECK-LABEL: c.func @_QQmain
+  ! CHECK:  %[[V_0:[0-9]+]] = fir.address_of(@_QFEn) : !fir.ref<i32> loc("{{.*}}if-loc.f90":3:
+  ! CHECK:  %[[V_1:[0-9]+]]:2 = hlfir.declare %[[V_0]] {uniq_name = "_QFEn"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>) loc("{{.*}}if-loc.f90":3:
+  ! CHECK:  %[[V_2:[0-9]+]] = fir.address_of(@_QFEx) : !fir.ref<i32> loc("{{.*}}if-loc.f90":3:
+  ! CHECK:  %[[V_3:[0-9]+]]:2 = hlfir.declare %[[V_2]] {uniq_name = "_QFEx"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>) loc("{{.*}}if-loc.f90":3:
+  ! CHECK:  %[[V_4:[0-9]+]] = fir.load %[[V_3]]#0 : !fir.ref<i32> loc("{{.*}}if-loc.f90":4:
+  ! CHECK:  %[[V_5:[0-9]+]] = arith.cmpi ne, %[[V_4]], %c1{{.*}} : i32 loc("{{.*}}if-loc.f90":4:
+  ! CHECK:  %[[V_6:[0-9]+]] = arith.xori %[[V_5]], %true{{[_0-9]*}} : i1 loc("{{.*}}if-loc.f90":4:
+  ! CHECK:  fir.if %[[V_6]] {
+  ! CHECK:    %[[V_18:[0-9]+]] = fir.load %[[V_1]]#0 : !fir.ref<i32> loc("{{.*}}if-loc.f90":5:
+  ! CHECK:    %[[V_19:[0-9]+]] = arith.addi %[[V_18]], %c1{{.*}} : i32 loc("{{.*}}if-loc.f90":5:
+  ! CHECK:    hlfir.assign %[[V_19]] to %[[V_1]]#0 : i32, !fir.ref<i32> loc("{{.*}}if-loc.f90":5:
+  ! CHECK:    %[[V_20:[0-9]+]] = fir.load %[[V_3]]#0 : !fir.ref<i32> loc("{{.*}}if-loc.f90":6:
+  ! CHECK:    %[[V_21:[0-9]+]] = arith.cmpi sgt, %[[V_20]], %c1{{.*}} : i32 loc("{{.*}}if-loc.f90":6:
+  ! CHECK:    %[[V_22:[0-9]+]] = arith.xori %[[V_21]], %true{{[_0-9]*}} : i1 loc("{{.*}}if-loc.f90":6:
+  ! CHECK:    fir.if %[[V_22]] {
+  ! CHECK:      %[[V_23:[0-9]+]] = fir.load %[[V_1]]#0 : !fir.ref<i32> loc("{{.*}}if-loc.f90":7:
+  ! CHECK:      %[[V_24:[0-9]+]] = arith.addi %[[V_23]], %c1{{.*}} : i32 loc("{{.*}}if-loc.f90":7:
+  ! CHECK:      hlfir.assign %[[V_24]] to %[[V_1]]#0 : i32, !fir.ref<i32> loc("{{.*}}if-loc.f90":7:
+  ! CHECK:    }
+  ! CHECK:  }
+  ! CHECK:  %[[V_9:[0-9]+]] = fir.call @_FortranAioBeginExternalListOutput{{.*}} loc("{{.*}}if-loc.f90":8:
+  ! CHECK:  return loc("{{.*}}if-loc.f90":9:
+  ! CHECK:}