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[Flang] Avoid crash when a function return is undefined (#151577)

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Properly terminate the StatementContext cleanup when a function return
value is undefined.

Fixes #126452
This commit is contained in:
Carlos Seo 2025-08-05 10:53:18 -03:00 committed by GitHub
parent 2444c4a698
commit 47ef3d069b
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GPG Key ID: B5690EEEBB952194
2 changed files with 14 additions and 1 deletions
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8
flang/lib/Lower/Bridge.cpp
View File

@ -1732,7 +1732,13 @@ private:
Fortran::lower::SymbolBox resultSymBox = lookupSymbol(resultSym);
mlir::Location loc = toLocation();
if (!resultSymBox) {
mlir::emitError(loc, "internal error when processing function return");
// Create a dummy undefined value of the expected return type.
// This prevents improper cleanup of StatementContext, which would lead
// to a crash due to a block with no terminator. See issue #126452.
mlir::FunctionType funcType = builder->getFunction().getFunctionType();
mlir::Type resultType = funcType.getResult(0);
mlir::Value undefResult = builder->create<fir::UndefOp>(loc, resultType);
genExitRoutine(false, undefResult);
return;
}
mlir::Value resultVal = resultSymBox.match(

7
flang/test/Lower/undef-func-result.f90 Normal file
View File

@ -0,0 +1,7 @@
!RUN: %flang -c %s -### 2>&1
function s(x) result(i)
!CHECK-WARNING: Function result is never defined
integer::x
procedure():: i
end function
end