[flang-commits] [flang] [flang] Fix spurious error messages due to INTRINSIC nested in BLOCK (PR #115889)

[Peter Klausler via flang-commits]

https://github.com/klausler created https://github.com/llvm/llvm-project/pull/115889

When skimmming executable parts to collect names used in procedure calls, it is important to exclude names that have local declarations in nested BLOCK constructs.  The mechanism for handling these nested declarations was catching only names whose declarations include an "entity-decl", and so names appearing in other declaration statements (like INTRINSIC and EXTERNAL statements) were not hidden from the scan, leading to absurd error messages when such names turn out to be procedures in the nested BLOCK construct but to not be procedures outside it.

This patch fixes the code that detects local declarations in BLOCK for all of the missed cases that don't use entity-decls; only INTRINSIC and EXTERNAL could affect the procedures whose names are of interest to the executable part skimmer, but perhaps future work will want to collect non-procedures as well, so I plugged all of the holes that I could find.

Fixes https://github.com/llvm/llvm-project/issues/115674.

>From 5e2788ca59daf88e6213cb6b336a618ef480dfe5 Mon Sep 17 00:00:00 2001
From: Peter Klausler <pklausler at nvidia.com>
Date: Tue, 12 Nov 2024 07:41:09 -0800
Subject: [PATCH] [flang] Fix spurious error messages due to INTRINSIC nested
 in BLOCK

When skimmming executable parts to collect names used in procedure calls,
it is important to exclude names that have local declarations in nested BLOCK
constructs.  The mechanism for handling these nested declarations was catching
only names whose declarations include an "entity-decl", and so names appearing
in other declaration statements (like INTRINSIC and EXTERNAL statements) were
not hidden from the scan, leading to absurd error messages when such names
turn out to be procedures in the nested BLOCK construct but to not be
procedures outside it.

This patch fixes the code that detects local declarations in BLOCK
for all of the missed cases that don't use entity-decls; only INTRINSIC
and EXTERNAL could affect the procedures whose names are of interest
to the executable part skimmer, but perhaps future work will want to
collect non-procedures as well, so I plugged all of the holes that I
could find.

Fixes https://github.com/llvm/llvm-project/issues/115674.
---
 flang/lib/Semantics/resolve-names.cpp | 53 +++++++++++++++++++++++++--
 flang/test/Semantics/bug115674.f90    |  9 +++++
 2 files changed, 59 insertions(+), 3 deletions(-)
 create mode 100644 flang/test/Semantics/bug115674.f90

diff --git a/flang/lib/Semantics/resolve-names.cpp b/flang/lib/Semantics/resolve-names.cpp
index e0a8246ebc752e..4b8cd447bcf19f 100644
--- a/flang/lib/Semantics/resolve-names.cpp
+++ b/flang/lib/Semantics/resolve-names.cpp
@@ -4787,10 +4787,13 @@ void DeclarationVisitor::Post(const parser::EntityDecl &x) {
   } else if (attrs.test(Attr::PARAMETER)) { // C882, C883
     Say(name, "Missing initialization for parameter '%s'"_err_en_US);
   }
-  if (auto *scopeSymbol{currScope().symbol()})
-    if (auto *details{scopeSymbol->detailsIf<DerivedTypeDetails>()})
-      if (details->isDECStructure())
+  if (auto *scopeSymbol{currScope().symbol()}) {
+    if (auto *details{scopeSymbol->detailsIf<DerivedTypeDetails>()}) {
+      if (details->isDECStructure()) {
         details->add_component(symbol);
+      }
+    }
+  }
 }
 
 void DeclarationVisitor::Post(const parser::PointerDecl &x) {
@@ -7660,10 +7663,54 @@ class ExecutionPartSkimmerBase {
     --blockDepth_;
     PopScope();
   }
+  // Note declarations of local names in BLOCK constructs.
+  // Don't have to worry about INTENT(), VALUE, or OPTIONAL
+  // (pertinent only to dummy arguments), ASYNCHRONOUS/VOLATILE,
+  // or accessibility attributes,
   bool Pre(const parser::EntityDecl &x) {
     Hide(std::get<parser::ObjectName>(x.t));
     return true;
   }
+  bool Pre(const parser::ObjectDecl &x) {
+    Hide(std::get<parser::ObjectName>(x.t));
+    return true;
+  }
+  bool Pre(const parser::PointerDecl &x) {
+    Hide(std::get<parser::Name>(x.t));
+    return true;
+  }
+  bool Pre(const parser::BindEntity &x) {
+    Hide(std::get<parser::Name>(x.t));
+    return true;
+  }
+  bool Pre(const parser::ContiguousStmt &x) {
+    for (const parser::Name &name : x.v) {
+      Hide(name);
+    }
+    return true;
+  }
+  bool Pre(const parser::DimensionStmt::Declaration &x) {
+    Hide(std::get<parser::Name>(x.t));
+    return true;
+  }
+  bool Pre(const parser::ExternalStmt &x) {
+    for (const parser::Name &name : x.v) {
+      Hide(name);
+    }
+    return true;
+  }
+  bool Pre(const parser::IntrinsicStmt &x) {
+    for (const parser::Name &name : x.v) {
+      Hide(name);
+    }
+    return true;
+  }
+  bool Pre(const parser::CodimensionStmt &x) {
+    for (const parser::CodimensionDecl &decl : x.v) {
+      Hide(std::get<parser::Name>(decl.t));
+    }
+    return true;
+  }
   void Post(const parser::ImportStmt &x) {
     if (x.kind == common::ImportKind::None ||
         x.kind == common::ImportKind::Only) {
diff --git a/flang/test/Semantics/bug115674.f90 b/flang/test/Semantics/bug115674.f90
new file mode 100644
index 00000000000000..87c527bb4297a8
--- /dev/null
+++ b/flang/test/Semantics/bug115674.f90
@@ -0,0 +1,9 @@
+!RUN: %flang_fc1 -fsyntax-only %s 2>&1 | FileCheck --allow-empty %s
+!CHECK-NOT: error:
+program main
+  sin = 1
+  block
+    intrinsic sin
+    print *, sin(0.)
+  end block
+end