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[flang] Bug fix for ambiguous references to data and functions

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Summary:
A program may erroneously reference the same name as both a data object
and as a function.  Some of these references were causing an internal
error in expression analysis.

It was already the case that a symbol referenced in a parse tree for a
call was changed from an `Entity` to a `ProcEntity`.  I added code to
detect when a symbol was referenced in a parse tree as an array element
gets changed from an `Entity` to an `ObjectEntity`.  Then, if an
`ObjectEntity` gets called as a function or a `ProcEntity` gets
referenced as a data object, errors get emitted.

This analysis was previously confined to the name resolution of the
specification part of a `ProgramTree`.  I added a pass to the execution
part of a `ProgramTree` to catch names declared in blocks.

Reviewers: tskeith, klausler, DavidTruby

Subscribers: llvm-commits

Tags: #llvm, #flang

Differential Revision: https://reviews.llvm.org/D82903
This commit is contained in:
Pete Steinfeld 2020-06-30 12:03:28 -07:00
parent bfdafa32a0
commit f9e24a563c
3 changed files with 57 additions and 2 deletions
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5
flang/lib/Semantics/expression.cpp
View file

@ -909,7 +909,10 @@ MaybeExpr ExpressionAnalyzer::Analyze(const parser::ArrayElement &ae) {
return std::nullopt;
} else if (baseExpr->Rank() == 0) {
if (const Symbol * symbol{GetLastSymbol(*baseExpr)}) {
Say("'%s' is not an array"_err_en_US, symbol->name());
if (!context_.HasError(symbol)) {
Say("'%s' is not an array"_err_en_US, symbol->name());
context_.SetError(const_cast<Symbol &>(*symbol));
}
}
} else if (std::optional<DataRef> dataRef{
ExtractDataRef(std::move(*baseExpr))}) {

10
flang/lib/Semantics/resolve-names.cpp
View file

@ -5505,7 +5505,15 @@ const parser::Name *DeclarationVisitor::ResolveDataRef(
},
[&](const Indirection<parser::ArrayElement> &y) {
Walk(y.value().subscripts);
return ResolveDataRef(y.value().base);
const parser::Name *name{ResolveDataRef(y.value().base)};
if (!name) {
} else if (!name->symbol->has<ProcEntityDetails>()) {
ConvertToObjectEntity(*name->symbol);
} else if (!context().HasError(*name->symbol)) {
SayWithDecl(*name, *name->symbol,
"Cannot reference function '%s' as data"_err_en_US);
}
return name;
},
[&](const Indirection<parser::CoindexedNamedObject> &y) {
Walk(y.value().imageSelector);

44
flang/test/Semantics/resolve93.f90 Normal file
View file

@ -0,0 +1,44 @@
! RUN: %S/test_errors.sh %s %t %f18
subroutine s1()
character(10) str
character(10) str1
!ERROR: Cannot reference function 'str' as data
print *, str(1:9), str(7)
block
character(10) str2
character(10) str3
!ERROR: Cannot reference function 'str1' as data
print *, str1(1:9), str1(7)
!ERROR: 'str2' is not an array
print *, str2(1:9), str2(7)
!ERROR: Cannot reference function 'str3' as data
print *, str3(7), str3(1:9)
end block
end subroutine s1
subroutine s2()
character(10) func
!ERROR: Cannot reference function 'func' as data
print *, func(7), func(1:9)
end subroutine s2
subroutine s3()
real(8) :: func
!ERROR: Cannot reference function 'func' as data
print *, func(7), func(1:6)
end subroutine s3
subroutine s4()
real(8) :: local
real(8) :: local1
!ERROR: Cannot reference function 'local' as data
print *, local(1:6), local(7)
!ERROR: Cannot reference function 'local1' as data
print *, local1(7), local1(1:6)
end subroutine s4
subroutine s5(arg)
integer :: iVar
external :: arg
iVar = loc(arg)
end subroutine s5