[flang-commits] [flang] 38272f4 - [flang] Create HostAssoc symbols for uplevel references

[Tim Keith via flang-commits]

Author: Tim Keith
Date: 2020-07-30T07:12:26-07:00
New Revision: 38272f45fed3f2233d54ff1495a4433f87215667

URL: https://github.com/llvm/llvm-project/commit/38272f45fed3f2233d54ff1495a4433f87215667
DIFF: https://github.com/llvm/llvm-project/commit/38272f45fed3f2233d54ff1495a4433f87215667.diff

LOG: [flang] Create HostAssoc symbols for uplevel references

To make it easier for lowering to identify which symbols from the host
are captured by internal subprograms, create HostAssocDetails for them.

In particular, if a symbol is referenced and it is contained in a
subprogram or main program that is not the same as the containing
program unit of the reference, a HostAssocDetails symbol is created
in the current scope.

Differential Revision: https://reviews.llvm.org/D84889

Added: 
    

Modified: 
    flang/lib/Semantics/resolve-names.cpp
    flang/lib/Semantics/tools.cpp
    flang/test/Semantics/symbol02.f90
    flang/test/Semantics/symbol03.f90
    flang/test/Semantics/symbol05.f90

Removed: 
    


################################################################################
diff  --git a/flang/lib/Semantics/resolve-names.cpp b/flang/lib/Semantics/resolve-names.cpp
index 50ea735d81d5..744eee19ba43 100644
--- a/flang/lib/Semantics/resolve-names.cpp
+++ b/flang/lib/Semantics/resolve-names.cpp
@@ -909,6 +909,7 @@ class DeclarationVisitor : public ArraySpecVisitor,
   void AddSaveName(std::set<SourceName> &, const SourceName &);
   void SetSaveAttr(Symbol &);
   bool HandleUnrestrictedSpecificIntrinsicFunction(const parser::Name &);
+  bool IsUplevelReference(const Symbol &);
   const parser::Name *FindComponent(const parser::Name *, const parser::Name &);
   bool CheckInitialDataTarget(const Symbol &, const SomeExpr &, SourceName);
   void CheckInitialProcTarget(const Symbol &, const parser::Name &, SourceName);
@@ -5429,7 +5430,10 @@ const parser::Name *DeclarationVisitor::ResolveName(const parser::Name &name) {
     if (CheckUseError(name)) {
       return nullptr; // reported an error
     }
-    if (IsDummy(*symbol) ||
+    if (IsUplevelReference(*symbol)) {
+      name.symbol = nullptr;
+      MakeSymbol(name, HostAssocDetails{*symbol});
+    } else if (IsDummy(*symbol) ||
         (!symbol->GetType() && FindCommonBlockContaining(*symbol))) {
       ConvertToObjectEntity(*symbol);
       ApplyImplicitRules(*symbol);
@@ -5453,6 +5457,16 @@ const parser::Name *DeclarationVisitor::ResolveName(const parser::Name &name) {
   return &name;
 }
 
+bool DeclarationVisitor::IsUplevelReference(const Symbol &symbol) {
+  const Scope *symbolUnit{FindProgramUnitContaining(symbol)};
+  if (symbolUnit == FindProgramUnitContaining(currScope())) {
+    return false;
+  } else {
+    Scope::Kind kind{DEREF(symbolUnit).kind()};
+    return kind == Scope::Kind::Subprogram || kind == Scope::Kind::MainProgram;
+  }
+}
+
 // base is a part-ref of a derived type; find the named component in its type.
 // Also handles intrinsic type parameter inquiries (%kind, %len) and
 // COMPLEX component references (%re, %im).

diff  --git a/flang/lib/Semantics/tools.cpp b/flang/lib/Semantics/tools.cpp
index 260701133396..d5ef9c76aa34 100644
--- a/flang/lib/Semantics/tools.cpp
+++ b/flang/lib/Semantics/tools.cpp
@@ -179,10 +179,21 @@ bool DoesScopeContain(const Scope *maybeAncestor, const Symbol &symbol) {
   return DoesScopeContain(maybeAncestor, symbol.owner());
 }
 
+static const Symbol &FollowHostAssoc(const Symbol &symbol) {
+  for (const Symbol *s{&symbol};;) {
+    const auto *details{s->detailsIf<HostAssocDetails>()};
+    if (!details) {
+      return *s;
+    }
+    s = &details->symbol();
+  }
+}
+
 bool IsHostAssociated(const Symbol &symbol, const Scope &scope) {
   const Scope *subprogram{FindProgramUnitContaining(scope)};
   return subprogram &&
-      DoesScopeContain(FindProgramUnitContaining(symbol), *subprogram);
+      DoesScopeContain(
+          FindProgramUnitContaining(FollowHostAssoc(symbol)), *subprogram);
 }
 
 bool IsInStmtFunction(const Symbol &symbol) {

diff  --git a/flang/test/Semantics/symbol02.f90 b/flang/test/Semantics/symbol02.f90
index 4d73edd66044..add42939e464 100644
--- a/flang/test/Semantics/symbol02.f90
+++ b/flang/test/Semantics/symbol02.f90
@@ -44,7 +44,7 @@ subroutine s2
    !REF: /m/x
    z = x
    !REF: /m/s/s2/z
-   !REF: /m/s/y
+   !DEF: /m/s/s2/y HostAssoc TYPE(t)
    z = y
    !REF: /m/s/s
    call s

diff  --git a/flang/test/Semantics/symbol03.f90 b/flang/test/Semantics/symbol03.f90
index 2f3620284a83..a398d8db40b0 100644
--- a/flang/test/Semantics/symbol03.f90
+++ b/flang/test/Semantics/symbol03.f90
@@ -11,7 +11,14 @@ program main
  !REF: /main/s
  subroutine s
   !DEF: /main/s/y (Implicit) ObjectEntity REAL(4)
-  !REF: /main/x
+  !DEF: /main/s/x HostAssoc INTEGER(4)
   y = x
+ contains
+  !DEF: /main/s/s2 (Subroutine) Subprogram
+  subroutine s2
+   !DEF: /main/s/s2/z (Implicit) ObjectEntity REAL(4)
+   !DEF: /main/s/s2/x HostAssoc INTEGER(4)
+   z = x
+  end subroutine
  end subroutine
 end program

diff  --git a/flang/test/Semantics/symbol05.f90 b/flang/test/Semantics/symbol05.f90
index 0c36384a6c4e..03f6fbbd989e 100644
--- a/flang/test/Semantics/symbol05.f90
+++ b/flang/test/Semantics/symbol05.f90
@@ -33,7 +33,7 @@ subroutine s2
 contains
  !DEF: /s2/s (Subroutine) Subprogram
  subroutine s
-  !REF: /s2/x
+  !DEF: /s2/s/x HostAssoc INTEGER(4)
   x = 1
   !DEF: /s2/s/w (Implicit) ObjectEntity INTEGER(4)
   w = 1