[flang] Handle DATA initialization of EQUIVALENCE'd objects

Objects that are storage associated by EQUIVALENCE and
initialized with DATA are initialized by creating a
compiler temporary data object in the same scope,
assigning it an offset, type, and size that covers the
transitive closure of the associated initialized original
symbols, and combining their initializers into one common
initializer for the temporary.

Some problems with offset assignment of EQUIVALENCE'd objects
in COMMON were exposed and corrected, and some more error
cases are checked.

Remove obsolete function.
Small bugfix (nested implied dos).
Add a test.
Fix struct/class warning.

Differential Revision: https://reviews.llvm.org/D85560

Author: klausler

flang/include/flang/Evaluate/initial-image.h

@@ -87,6 +87,8 @@ class InitialImage {
 
   void AddPointer(ConstantSubscript, const Expr<SomeType> &);
 
+  void Incorporate(ConstantSubscript, const InitialImage &);
+
   // Conversions to constant initializers
   std::optional<Expr<SomeType>> AsConstant(FoldingContext &,
       const DynamicType &, const ConstantSubscripts &,

flang/include/flang/Parser/parsing.h

@@ -62,8 +62,6 @@ class Parsing {
         o, cooked_.GetProvenanceRange(CharBlock(at)), message, echoSourceLine);
   }
 
-  bool ForTesting(std::string path, llvm::raw_ostream &);
-
 private:
   Options options_;
   CookedSource cooked_;

flang/include/flang/Semantics/semantics.h

@@ -170,6 +170,7 @@ class SemanticsContext {
   void ActivateIndexVar(const parser::Name &, IndexVarKind);
   void DeactivateIndexVar(const parser::Name &);
   SymbolVector GetIndexVars(IndexVarKind);
+  SourceName GetTempName(const Scope &);
 
 private:
   void CheckIndexVarRedefine(
@@ -196,6 +197,7 @@ class SemanticsContext {
     IndexVarKind kind;
   };
   std::map<SymbolRef, const IndexVarInfo> activeIndexVars_;
+  std::vector<std::string> tempNames_;
 };
 
 class Semantics {

flang/include/flang/Semantics/type.h

@@ -53,7 +53,7 @@ class Bound {
   static Bound Assumed() { return Bound(Category::Assumed); }
   static Bound Deferred() { return Bound(Category::Deferred); }
   explicit Bound(MaybeSubscriptIntExpr &&expr) : expr_{std::move(expr)} {}
-  explicit Bound(int bound);
+  explicit Bound(common::ConstantSubscript bound);
   Bound(const Bound &) = default;
   Bound(Bound &&) = default;
   Bound &operator=(const Bound &) = default;

flang/lib/Evaluate/initial-image.cpp

@@ -9,6 +9,7 @@
 #include "flang/Evaluate/initial-image.h"
 #include "flang/Semantics/scope.h"
 #include "flang/Semantics/tools.h"
+#include <cstring>
 
 namespace Fortran::evaluate {
 
@@ -53,6 +54,13 @@ void InitialImage::AddPointer(
   pointers_.emplace(offset, pointer);
 }
 
+void InitialImage::Incorporate(
+    ConstantSubscript offset, const InitialImage &that) {
+  CHECK(that.pointers_.empty()); // pointers are not allowed in EQUIVALENCE
+  CHECK(offset + that.size() <= size());
+  std::memcpy(&data_[offset], &that.data_[0], that.size());
+}
+
 // Classes used with common::SearchTypes() to (re)construct Constant<> values
 // of the right type to initialize each symbol from the values that have
 // been placed into its initialization image by DATA statements.

flang/lib/Parser/parsing.cpp

@@ -123,24 +123,4 @@ void Parsing::Parse(llvm::raw_ostream &out) {
 
 void Parsing::ClearLog() { log_.clear(); }
 
-bool Parsing::ForTesting(std::string path, llvm::raw_ostream &err) {
-  llvm::raw_null_ostream NullStream;
-  Prescan(path, Options{});
-  if (messages_.AnyFatalError()) {
-    messages_.Emit(err, cooked_);
-    err << "could not scan " << path << '\n';
-    return false;
-  }
-  Parse(NullStream);
-  messages_.Emit(err, cooked_);
-  if (!consumedWholeFile_) {
-    EmitMessage(err, finalRestingPlace_, "parser FAIL; final position");
-    return false;
-  }
-  if (messages_.AnyFatalError() || !parseTree_.has_value()) {
-    err << "could not parse " << path << '\n';
-    return false;
-  }
-  return true;
-}
 } // namespace Fortran::parser

flang/lib/Semantics/CMakeLists.txt

@@ -26,6 +26,7 @@ add_flang_library(FortranSemantics
   check-select-type.cpp
   check-stop.cpp
   compute-offsets.cpp
+  data-to-inits.cpp
   expression.cpp
   mod-file.cpp
   pointer-assignment.cpp