[flang-commits] [flang] [flang] Catch name resolution error due to global scoping (PR #77683)
Peter Klausler via flang-commits
flang-commits at lists.llvm.org
Fri Jan 12 14:05:26 PST 2024
https://github.com/klausler updated https://github.com/llvm/llvm-project/pull/77683
>From 369d09660dc89bc639620edc6b4739b95caf898d Mon Sep 17 00:00:00 2001
From: Peter Klausler <pklausler at nvidia.com>
Date: Wed, 10 Jan 2024 12:13:31 -0800
Subject: [PATCH] [flang] Catch name resolution error due to global scoping
In
CALL FOO
PRINT *, ABS(FOO)
we currently resolve the first FOO to a global external subprogram,
but then the second FOO is treated as an implicitly typed local
variable. This happens because the name FOO is not present in the
local scope.
Fix by adding FOO to the local scope using a place-holding
HostAssocDetails symbol whose existence prevents the creation of
another FOO in the local scope. The symbol stored in the parser::Name
parse tree nodes or used in typed expressions will all continue to
point to the global external subprogram.
Resolves llvm-test-suite/Fortran/gfortran/regression/pr71859.f90.
---
.../include/flang/Evaluate/characteristics.h | 10 +-
flang/lib/Evaluate/characteristics.cpp | 98 ++++++++++++++++---
flang/lib/Semantics/expression.cpp | 30 +++---
flang/lib/Semantics/resolve-names.cpp | 13 ++-
flang/test/Semantics/call24.f90 | 4 +
flang/test/Semantics/call25.f90 | 2 +-
flang/test/Semantics/entry01.f90 | 1 -
flang/test/Semantics/local-vs-global.f90 | 4 +
flang/test/Semantics/reshape.f90 | 2 +-
flang/test/Semantics/resolve09.f90 | 9 +-
10 files changed, 131 insertions(+), 42 deletions(-)
diff --git a/flang/include/flang/Evaluate/characteristics.h b/flang/include/flang/Evaluate/characteristics.h
index 43f8134b93c5c8..c2cb2f568dffc9 100644
--- a/flang/include/flang/Evaluate/characteristics.h
+++ b/flang/include/flang/Evaluate/characteristics.h
@@ -227,7 +227,7 @@ struct DummyDataObject {
std::optional<std::string> *warning = nullptr) const;
static std::optional<DummyDataObject> Characterize(
const semantics::Symbol &, FoldingContext &);
- bool CanBePassedViaImplicitInterface() const;
+ bool CanBePassedViaImplicitInterface(std::string *whyNot = nullptr) const;
llvm::raw_ostream &Dump(llvm::raw_ostream &) const;
TypeAndShape type;
@@ -248,7 +248,7 @@ struct DummyProcedure {
bool operator!=(const DummyProcedure &that) const { return !(*this == that); }
bool IsCompatibleWith(
const DummyProcedure &, std::string *whyNot = nullptr) const;
- bool CanBePassedViaImplicitInterface() const;
+ bool CanBePassedViaImplicitInterface(std::string *whyNot = nullptr) const;
llvm::raw_ostream &Dump(llvm::raw_ostream &) const;
CopyableIndirection<Procedure> procedure;
@@ -282,7 +282,7 @@ struct DummyArgument {
void SetOptional(bool = true);
common::Intent GetIntent() const;
void SetIntent(common::Intent);
- bool CanBePassedViaImplicitInterface() const;
+ bool CanBePassedViaImplicitInterface(std::string *whyNot = nullptr) const;
bool IsTypelessIntrinsicDummy() const;
bool IsCompatibleWith(const DummyArgument &, std::string *whyNot = nullptr,
std::optional<std::string> *warning = nullptr) const;
@@ -325,7 +325,7 @@ struct FunctionResult {
return std::get_if<TypeAndShape>(&u);
}
void SetType(DynamicType t) { std::get<TypeAndShape>(u).set_type(t); }
- bool CanBeReturnedViaImplicitInterface() const;
+ bool CanBeReturnedViaImplicitInterface(std::string *whyNot = nullptr) const;
bool IsCompatibleWith(
const FunctionResult &, std::string *whyNot = nullptr) const;
@@ -377,7 +377,7 @@ struct Procedure {
return !attrs.test(Attr::ImplicitInterface);
}
int FindPassIndex(std::optional<parser::CharBlock>) const;
- bool CanBeCalledViaImplicitInterface() const;
+ bool CanBeCalledViaImplicitInterface(std::string *whyNot = nullptr) const;
bool CanOverride(const Procedure &, std::optional<int> passIndex) const;
bool IsCompatibleWith(const Procedure &, std::string *whyNot = nullptr,
const SpecificIntrinsic * = nullptr,
diff --git a/flang/lib/Evaluate/characteristics.cpp b/flang/lib/Evaluate/characteristics.cpp
index 83ef5d069d3ccc..90b8616fda27ea 100644
--- a/flang/lib/Evaluate/characteristics.cpp
+++ b/flang/lib/Evaluate/characteristics.cpp
@@ -419,24 +419,45 @@ std::optional<DummyDataObject> DummyDataObject::Characterize(
return std::nullopt;
}
-bool DummyDataObject::CanBePassedViaImplicitInterface() const {
+bool DummyDataObject::CanBePassedViaImplicitInterface(
+ std::string *whyNot) const {
if ((attrs &
Attrs{Attr::Allocatable, Attr::Asynchronous, Attr::Optional,
Attr::Pointer, Attr::Target, Attr::Value, Attr::Volatile})
.any()) {
+ if (whyNot) {
+ *whyNot = "a dummy argument has the allocatable, asynchronous, optional, "
+ "pointer, target, value, or volatile attribute";
+ }
return false; // 15.4.2.2(3)(a)
} else if ((type.attrs() &
TypeAndShape::Attrs{TypeAndShape::Attr::AssumedShape,
TypeAndShape::Attr::AssumedRank,
TypeAndShape::Attr::Coarray})
.any()) {
+ if (whyNot) {
+ *whyNot = "a dummy argument is assumed-shape, assumed-rank, or a coarray";
+ }
return false; // 15.4.2.2(3)(b-d)
} else if (type.type().IsPolymorphic()) {
+ if (whyNot) {
+ *whyNot = "a dummy argument is polymorphic";
+ }
return false; // 15.4.2.2(3)(f)
} else if (cudaDataAttr) {
+ if (whyNot) {
+ *whyNot = "a dummy argument has a CUDA data attribute";
+ }
return false;
} else if (const auto *derived{GetDerivedTypeSpec(type.type())}) {
- return derived->parameters().empty(); // 15.4.2.2(3)(e)
+ if (derived->parameters().empty()) { // 15.4.2.2(3)(e)
+ return true;
+ } else {
+ if (whyNot) {
+ *whyNot = "a dummy argument has derived type parameters";
+ }
+ return false;
+ }
} else {
return true;
}
@@ -495,8 +516,12 @@ bool DummyProcedure::IsCompatibleWith(
return true;
}
-bool DummyProcedure::CanBePassedViaImplicitInterface() const {
+bool DummyProcedure::CanBePassedViaImplicitInterface(
+ std::string *whyNot) const {
if ((attrs & Attrs{Attr::Optional, Attr::Pointer}).any()) {
+ if (whyNot) {
+ *whyNot = "a dummy procedure is optional or a pointer";
+ }
return false; // 15.4.2.2(3)(a)
}
return true;
@@ -897,11 +922,11 @@ common::Intent DummyArgument::GetIntent() const {
u);
}
-bool DummyArgument::CanBePassedViaImplicitInterface() const {
+bool DummyArgument::CanBePassedViaImplicitInterface(std::string *whyNot) const {
if (const auto *object{std::get_if<DummyDataObject>(&u)}) {
- return object->CanBePassedViaImplicitInterface();
+ return object->CanBePassedViaImplicitInterface(whyNot);
} else if (const auto *proc{std::get_if<DummyProcedure>(&u)}) {
- return proc->CanBePassedViaImplicitInterface();
+ return proc->CanBePassedViaImplicitInterface(whyNot);
} else {
return true;
}
@@ -972,13 +997,23 @@ bool FunctionResult::IsAssumedLengthCharacter() const {
}
}
-bool FunctionResult::CanBeReturnedViaImplicitInterface() const {
+bool FunctionResult::CanBeReturnedViaImplicitInterface(
+ std::string *whyNot) const {
if (attrs.test(Attr::Pointer) || attrs.test(Attr::Allocatable)) {
+ if (whyNot) {
+ *whyNot = "the function result is a pointer or allocatable";
+ }
return false; // 15.4.2.2(4)(b)
} else if (cudaDataAttr) {
+ if (whyNot) {
+ *whyNot = "the function result has CUDA attributes";
+ }
return false;
} else if (const auto *typeAndShape{GetTypeAndShape()}) {
if (typeAndShape->Rank() > 0) {
+ if (whyNot) {
+ *whyNot = "the function result is an array";
+ }
return false; // 15.4.2.2(4)(a)
} else {
const DynamicType &type{typeAndShape->type()};
@@ -988,31 +1023,52 @@ bool FunctionResult::CanBeReturnedViaImplicitInterface() const {
return true;
} else if (const auto *param{type.charLengthParamValue()}) {
if (const auto &expr{param->GetExplicit()}) {
- return IsConstantExpr(*expr); // 15.4.2.2(4)(c)
+ if (IsConstantExpr(*expr)) { // 15.4.2.2(4)(c)
+ return true;
+ } else {
+ if (whyNot) {
+ *whyNot = "the function result's length is not constant";
+ }
+ return false;
+ }
} else if (param->isAssumed()) {
return true;
}
}
+ if (whyNot) {
+ *whyNot = "the function result's length is not known to the caller";
+ }
return false;
case TypeCategory::Derived:
- if (!type.IsPolymorphic()) {
+ if (type.IsPolymorphic()) {
+ if (whyNot) {
+ *whyNot = "the function result is polymorphic";
+ }
+ return false;
+ } else {
const auto &spec{type.GetDerivedTypeSpec()};
for (const auto &pair : spec.parameters()) {
if (const auto &expr{pair.second.GetExplicit()}) {
if (!IsConstantExpr(*expr)) {
+ if (whyNot) {
+ *whyNot = "the function result's derived type has a "
+ "non-constant parameter";
+ }
return false; // 15.4.2.2(4)(c)
}
}
}
return true;
}
- return false;
default:
return true;
}
}
} else {
- return false; // 15.4.2.2(4)(b) - procedure pointer
+ if (whyNot) {
+ *whyNot = "the function result has unknown type or shape";
+ }
+ return false; // 15.4.2.2(4)(b) - procedure pointer?
}
}
@@ -1343,20 +1399,30 @@ std::optional<Procedure> Procedure::FromActuals(const ProcedureDesignator &proc,
return callee;
}
-bool Procedure::CanBeCalledViaImplicitInterface() const {
- // TODO: Pass back information on why we return false
- if (attrs.test(Attr::Elemental) || attrs.test(Attr::BindC)) {
+bool Procedure::CanBeCalledViaImplicitInterface(std::string *whyNot) const {
+ if (attrs.test(Attr::Elemental)) {
+ if (whyNot) {
+ *whyNot = "the procedure is elemental";
+ }
+ return false; // 15.4.2.2(5,6)
+ } else if (attrs.test(Attr::BindC)) {
+ if (whyNot) {
+ *whyNot = "the procedure is BIND(C)";
+ }
return false; // 15.4.2.2(5,6)
} else if (cudaSubprogramAttrs &&
*cudaSubprogramAttrs != common::CUDASubprogramAttrs::Host &&
*cudaSubprogramAttrs != common::CUDASubprogramAttrs::Global) {
+ if (whyNot) {
+ *whyNot = "the procedure is CUDA but neither HOST nor GLOBAL";
+ }
return false;
} else if (IsFunction() &&
- !functionResult->CanBeReturnedViaImplicitInterface()) {
+ !functionResult->CanBeReturnedViaImplicitInterface(whyNot)) {
return false;
} else {
for (const DummyArgument &arg : dummyArguments) {
- if (!arg.CanBePassedViaImplicitInterface()) {
+ if (!arg.CanBePassedViaImplicitInterface(whyNot)) {
return false;
}
}
diff --git a/flang/lib/Semantics/expression.cpp b/flang/lib/Semantics/expression.cpp
index ddaa1e8a3e70f2..bfc380183e23f5 100644
--- a/flang/lib/Semantics/expression.cpp
+++ b/flang/lib/Semantics/expression.cpp
@@ -3088,21 +3088,18 @@ const Assignment *ExpressionAnalyzer::Analyze(
}
static bool IsExternalCalledImplicitly(
- parser::CharBlock callSite, const ProcedureDesignator &proc) {
- if (const auto *symbol{proc.GetSymbol()}) {
- return symbol->has<semantics::SubprogramDetails>() &&
- symbol->owner().IsGlobal() &&
- (!symbol->scope() /*ENTRY*/ ||
- !symbol->scope()->sourceRange().Contains(callSite));
- } else {
- return false;
- }
+ parser::CharBlock callSite, const Symbol *symbol) {
+ return symbol && symbol->owner().IsGlobal() &&
+ symbol->has<semantics::SubprogramDetails>() &&
+ (!symbol->scope() /*ENTRY*/ ||
+ !symbol->scope()->sourceRange().Contains(callSite));
}
std::optional<characteristics::Procedure> ExpressionAnalyzer::CheckCall(
parser::CharBlock callSite, const ProcedureDesignator &proc,
ActualArguments &arguments) {
- bool treatExternalAsImplicit{IsExternalCalledImplicitly(callSite, proc)};
+ bool treatExternalAsImplicit{
+ IsExternalCalledImplicitly(callSite, proc.GetSymbol())};
const Symbol *procSymbol{proc.GetSymbol()};
std::optional<characteristics::Procedure> chars;
if (procSymbol && procSymbol->has<semantics::ProcEntityDetails>() &&
@@ -3138,10 +3135,15 @@ std::optional<characteristics::Procedure> ExpressionAnalyzer::CheckCall(
}
bool ok{true};
if (chars) {
- if (treatExternalAsImplicit && !chars->CanBeCalledViaImplicitInterface()) {
- Say(callSite,
- "References to the procedure '%s' require an explicit interface"_err_en_US,
- DEREF(procSymbol).name());
+ std::string whyNot;
+ if (treatExternalAsImplicit &&
+ !chars->CanBeCalledViaImplicitInterface(&whyNot)) {
+ if (auto *msg{Say(callSite,
+ "References to the procedure '%s' require an explicit interface"_err_en_US,
+ DEREF(procSymbol).name())};
+ msg && !whyNot.empty()) {
+ msg->Attach(callSite, "%s"_because_en_US, whyNot);
+ }
}
const SpecificIntrinsic *specificIntrinsic{proc.GetSpecificIntrinsic()};
bool procIsDummy{procSymbol && IsDummy(*procSymbol)};
diff --git a/flang/lib/Semantics/resolve-names.cpp b/flang/lib/Semantics/resolve-names.cpp
index 64fc7de120873a..6a514f699e0f7a 100644
--- a/flang/lib/Semantics/resolve-names.cpp
+++ b/flang/lib/Semantics/resolve-names.cpp
@@ -7756,6 +7756,11 @@ void ResolveNamesVisitor::HandleProcedureName(
if (!symbol->attrs().test(Attr::INTRINSIC)) {
if (CheckImplicitNoneExternal(name.source, *symbol)) {
MakeExternal(*symbol);
+ // Create a place-holder HostAssocDetails symbol to preclude later
+ // use of this name as a local symbol; but don't actually use this new
+ // HostAssocDetails symbol in expressions.
+ MakeHostAssocSymbol(name, *symbol);
+ name.symbol = symbol;
}
}
CheckEntryDummyUse(name.source, symbol);
@@ -7763,7 +7768,13 @@ void ResolveNamesVisitor::HandleProcedureName(
} else if (CheckUseError(name)) {
// error was reported
} else {
- symbol = &Resolve(name, symbol)->GetUltimate();
+ symbol = &symbol->GetUltimate();
+ if (!name.symbol ||
+ (name.symbol->has<HostAssocDetails>() && symbol->owner().IsGlobal() &&
+ (symbol->has<ProcEntityDetails>() ||
+ symbol->has<SubprogramDetails>()))) {
+ name.symbol = symbol;
+ }
CheckEntryDummyUse(name.source, symbol);
bool convertedToProcEntity{ConvertToProcEntity(*symbol)};
if (convertedToProcEntity && !symbol->attrs().test(Attr::EXTERNAL) &&
diff --git a/flang/test/Semantics/call24.f90 b/flang/test/Semantics/call24.f90
index 5fbb441908167f..78ee17b4886764 100644
--- a/flang/test/Semantics/call24.f90
+++ b/flang/test/Semantics/call24.f90
@@ -27,18 +27,22 @@ subroutine test()
! descriptor involved, copy-in/copy-out...)
!ERROR: References to the procedure 'foo' require an explicit interface
+ !BECAUSE: a dummy argument has the allocatable, asynchronous, optional, pointer, target, value, or volatile attribute
call foo(a_pointer)
! This call would be error if the interface was explicit here.
!ERROR: References to the procedure 'foo' require an explicit interface
+ !BECAUSE: a dummy argument has the allocatable, asynchronous, optional, pointer, target, value, or volatile attribute
call foo(an_array)
!ERROR: References to the procedure 'bar' require an explicit interface
+ !BECAUSE: a dummy procedure is optional or a pointer
!WARNING: If the procedure's interface were explicit, this reference would be in error
!BECAUSE: Actual argument associated with procedure pointer dummy argument 'a_pointer=' must be a pointer unless INTENT(IN)
call bar(sin)
!ERROR: References to the procedure 'baz' require an explicit interface
+ !BECAUSE: a dummy procedure is optional or a pointer
call baz(sin)
end subroutine
diff --git a/flang/test/Semantics/call25.f90 b/flang/test/Semantics/call25.f90
index d6ecd1320463f3..3b683fe4e3c4f3 100644
--- a/flang/test/Semantics/call25.f90
+++ b/flang/test/Semantics/call25.f90
@@ -1,4 +1,4 @@
-! RUN: not %flang -fsyntax-only 2>&1 %s | FileCheck %s
+! RUN: not %flang -fsyntax-only -pedantic 2>&1 %s | FileCheck %s
module m
contains
subroutine subr1(f)
diff --git a/flang/test/Semantics/entry01.f90 b/flang/test/Semantics/entry01.f90
index 64bd954f8ae0fe..f1e16fc86a566f 100644
--- a/flang/test/Semantics/entry01.f90
+++ b/flang/test/Semantics/entry01.f90
@@ -137,7 +137,6 @@ subroutine externals
entry iok1
integer :: ix
!ERROR: Cannot call subroutine 'iproc' like a function
- !ERROR: Function result characteristics are not known
ix = iproc()
entry iproc
end subroutine
diff --git a/flang/test/Semantics/local-vs-global.f90 b/flang/test/Semantics/local-vs-global.f90
index d903e431f2ae2d..d1f0a666a64512 100644
--- a/flang/test/Semantics/local-vs-global.f90
+++ b/flang/test/Semantics/local-vs-global.f90
@@ -74,6 +74,7 @@ program test
call block_data_before_2
call explicit_before_1(1.)
!ERROR: References to the procedure 'explicit_before_2' require an explicit interface
+ !BECAUSE: a dummy argument has the allocatable, asynchronous, optional, pointer, target, value, or volatile attribute
call explicit_before_2(1.)
!WARNING: If the procedure's interface were explicit, this reference would be in error
!BECAUSE: Dummy argument 'a=' (#1) is not OPTIONAL and is not associated with an actual argument in this procedure reference
@@ -83,6 +84,7 @@ program test
call implicit_before_2
print *, explicit_func_before_1(1.)
!ERROR: References to the procedure 'explicit_func_before_2' require an explicit interface
+ !BECAUSE: a dummy argument has the allocatable, asynchronous, optional, pointer, target, value, or volatile attribute
print *, explicit_func_before_2(1.)
!WARNING: If the procedure's interface were explicit, this reference would be in error
!BECAUSE: Dummy argument 'a=' (#1) is not OPTIONAL and is not associated with an actual argument in this procedure reference
@@ -96,6 +98,7 @@ program test
call block_data_after_2
call explicit_after_1(1.)
!ERROR: References to the procedure 'explicit_after_2' require an explicit interface
+ !BECAUSE: a dummy argument has the allocatable, asynchronous, optional, pointer, target, value, or volatile attribute
call explicit_after_2(1.)
!WARNING: If the procedure's interface were explicit, this reference would be in error
!BECAUSE: Dummy argument 'a=' (#1) is not OPTIONAL and is not associated with an actual argument in this procedure reference
@@ -105,6 +108,7 @@ program test
call implicit_after_2
print *, explicit_func_after_1(1.)
!ERROR: References to the procedure 'explicit_func_after_2' require an explicit interface
+ !BECAUSE: a dummy argument has the allocatable, asynchronous, optional, pointer, target, value, or volatile attribute
print *, explicit_func_after_2(1.)
!WARNING: If the procedure's interface were explicit, this reference would be in error
!BECAUSE: Dummy argument 'a=' (#1) is not OPTIONAL and is not associated with an actual argument in this procedure reference
diff --git a/flang/test/Semantics/reshape.f90 b/flang/test/Semantics/reshape.f90
index ea302ceed66aad..b3b96985affc7a 100644
--- a/flang/test/Semantics/reshape.f90
+++ b/flang/test/Semantics/reshape.f90
@@ -56,7 +56,7 @@ program reshaper
!ERROR: Size of 'shape=' argument must not be greater than 15
CALL ext_sub(RESHAPE([(n, n=1,20)], &
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]))
- !WARNING: Reference to the procedure 'ext_sub' has an implicit interface that is distinct from another reference: incompatible dummy argument #1: incompatible dummy data object shapes
+ !ERROR: Reference to the procedure 'ext_sub' has an implicit interface that is distinct from another reference: incompatible dummy argument #1: incompatible dummy data object shapes
!ERROR: 'shape=' argument must not have a negative extent
CALL ext_sub(RESHAPE([(n, n=1,20)], [1, -5, 3]))
!ERROR: 'order=' argument has unacceptable rank 2
diff --git a/flang/test/Semantics/resolve09.f90 b/flang/test/Semantics/resolve09.f90
index 6335de1e232749..c5e4277b3b6114 100644
--- a/flang/test/Semantics/resolve09.f90
+++ b/flang/test/Semantics/resolve09.f90
@@ -18,7 +18,6 @@ subroutine s
!ERROR: Cannot call function 'f' like a subroutine
call f
!ERROR: Cannot call subroutine 's' like a function
- !ERROR: Function result characteristics are not known
i = s()
contains
function f()
@@ -71,8 +70,6 @@ subroutine s4
import, none
integer :: i
!ERROR: 'm' is not a callable procedure
- i = m()
- !ERROR: 'm' is not a callable procedure
call m()
end block
end
@@ -126,3 +123,9 @@ subroutine s9
!ERROR: Cannot call subroutine 'p2' like a function
print *, x%p2()
end subroutine
+
+subroutine s10
+ call a10
+ !ERROR: Actual argument for 'a=' may not be a procedure
+ print *, abs(a10)
+end
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