Merge pull request lfortran#4552 from Pranavchiku/gh4544

enh: disable warning when global save attr is present

src/lfortran/semantics/ast_common_visitor.h

@@ -1021,6 +1021,9 @@ class CommonVisitor : public AST::BaseVisitor<Derived> {
     std::map<uint32_t, std::map<std::string, ASR::symbol_t*>> &instantiate_symbols;
     std::vector<ASR::stmt_t*> &data_structure;
 
+    // global save variable
+    bool is_global_save_enabled = false;
+
     // implied do loop nesting
     int idl_nesting_level = 0;
 
@@ -1999,6 +2002,25 @@ class CommonVisitor : public AST::BaseVisitor<Derived> {
         }
     }
 
+
+    template <typename T>
+    void check_if_global_save_is_enabled(T &x) {
+        for ( size_t i = 0; i < x.n_decl; i++ ) {
+            if ( AST::is_a<AST::Declaration_t>(*x.m_decl[i]) ) {
+                AST::Declaration_t* decl = AST::down_cast<AST::Declaration_t>(x.m_decl[i]);
+                if ( decl->n_attributes > 0 && decl->n_syms == 0 &&
+                    decl->m_trivia == nullptr &&
+                    AST::is_a<AST::SimpleAttribute_t>(*decl->m_attributes[0]) ) {
+                    AST::SimpleAttribute_t* attr = AST::down_cast<AST::SimpleAttribute_t>(decl->m_attributes[0]);
+                    if ( attr->m_attr == AST::simple_attributeType::AttrSave ) {
+                        is_global_save_enabled = true;
+                        break;
+                    }
+                }
+            }
+        }
+    }
+
     void create_external_function(std::string sym, Location loc, ASR::ttype_t* determined_type = nullptr) {
         if (compiler_options.implicit_interface) {
             bool is_subroutine = false;
@@ -3205,11 +3227,13 @@ class CommonVisitor : public AST::BaseVisitor<Derived> {
                 }
                 if (is_Function && implicit_save && !is_save) {
                     // throw warning to that particular variable
-                    diag.semantic_warning_label(
-                        "Assuming implicit save attribute for variable declaration",
-                        {x.m_syms[i].loc},
-                        "help: add explicit save attribute or parameter attribute or initialize in a separate statement"
-                    );
+                    if ( !is_global_save_enabled ) {
+                        diag.semantic_warning_label(
+                            "Assuming implicit save attribute for variable declaration",
+                            {x.m_syms[i].loc},
+                            "help: add explicit save attribute or parameter attribute or initialize in a separate statement"
+                        );
+                    }
                 }
                 if( std::find(excluded_from_symtab.begin(), excluded_from_symtab.end(), sym) == excluded_from_symtab.end() ) {
                     if ( !is_implicitly_declared && !is_external) {

src/lfortran/semantics/ast_symboltable_visitor.cpp

@@ -514,6 +514,8 @@ class SymbolTableVisitor : public CommonVisitor<SymbolTableVisitor> {
             }
         }
         simd_variables.clear();
+        bool is_global_save_enabled_copy = is_global_save_enabled;
+        check_if_global_save_is_enabled( x );
         for (size_t i=0; i<x.n_use; i++) {
             visit_unit_decl1(*x.m_use[i]);
         }
@@ -559,6 +561,7 @@ class SymbolTableVisitor : public CommonVisitor<SymbolTableVisitor> {
 
         fix_type_info(ASR::down_cast2<ASR::Program_t>(tmp));
         mark_common_blocks_as_declared();
+        is_global_save_enabled = is_global_save_enabled_copy;
     }
 
     bool subroutine_contains_entry_function(std::string subroutine_name, AST::stmt_t** body, size_t n_body) {
@@ -939,6 +942,9 @@ class SymbolTableVisitor : public CommonVisitor<SymbolTableVisitor> {
         char *bindc_name=nullptr;
         extract_bind(x, current_procedure_abi_type, bindc_name);
 
+        // iterate over declarations and check if global save is present
+        bool is_global_save_enabled_copy = is_global_save_enabled;
+        check_if_global_save_is_enabled( x );
         for (size_t i=0; i<x.n_use; i++) {
             visit_unit_decl1(*x.m_use[i]);
         }
@@ -1124,6 +1130,7 @@ class SymbolTableVisitor : public CommonVisitor<SymbolTableVisitor> {
         in_Subroutine = false;
         is_template = false;
         mark_common_blocks_as_declared();
+        is_global_save_enabled = is_global_save_enabled_copy;
     }
 
     AST::AttrType_t* find_return_type(AST::decl_attribute_t** attributes,
@@ -1268,6 +1275,9 @@ class SymbolTableVisitor : public CommonVisitor<SymbolTableVisitor> {
         char *bindc_name=nullptr;
         extract_bind(x, current_procedure_abi_type, bindc_name);
 
+        // iterate over declarations and check if global save is present
+        bool is_global_save_enabled_copy = is_global_save_enabled;
+        check_if_global_save_is_enabled( x );
         for (size_t i=0; i<x.n_use; i++) {
             visit_unit_decl1(*x.m_use[i]);
         }
@@ -1549,6 +1559,7 @@ class SymbolTableVisitor : public CommonVisitor<SymbolTableVisitor> {
         current_function_dependencies = current_function_dependencies_copy;
         in_Subroutine = false;
         mark_common_blocks_as_declared();
+        is_global_save_enabled = is_global_save_enabled_copy;
     }
 
     void visit_Declaration(const AST::Declaration_t& x) {

tests/reference/asr-save3-025da43.json

@@ -0,0 +1,13 @@
+{
+    "basename": "asr-save3-025da43",
+    "cmd": "lfortran --show-asr --no-color {infile} -o {outfile}",
+    "infile": "tests/save3.f90",
+    "infile_hash": "73a25f7c7513eff87c70b3f4e4d291178ff58078c3f57c81f356d77f",
+    "outfile": null,
+    "outfile_hash": null,
+    "stdout": "asr-save3-025da43.stdout",
+    "stdout_hash": "7b1b85844dc907929fc93c75f7d95194967a2bd2c7fbb458fb2fbac4",
+    "stderr": null,
+    "stderr_hash": null,
+    "returncode": 0
+}

tests/reference/asr-save3-025da43.stdout

@@ -0,0 +1,59 @@
+(TranslationUnit
+    (SymbolTable
+        1
+        {
+            f:
+                (Function
+                    (SymbolTable
+                        2
+                        {
+                            var:
+                                (Variable
+                                    2
+                                    var
+                                    []
+                                    Local
+                                    (RealConstant
+                                        0.000000
+                                        (Real 4)
+                                    )
+                                    (RealConstant
+                                        0.000000
+                                        (Real 4)
+                                    )
+                                    Save
+                                    (Real 4)
+                                    ()
+                                    Source
+                                    Public
+                                    Required
+                                    .false.
+                                )
+                        })
+                    f
+                    (FunctionType
+                        []
+                        ()
+                        Source
+                        Implementation
+                        ()
+                        .false.
+                        .false.
+                        .false.
+                        .false.
+                        .false.
+                        []
+                        .false.
+                    )
+                    []
+                    []
+                    []
+                    ()
+                    Public
+                    .false.
+                    .false.
+                    ()
+                )
+        })
+    []
+)

tests/save3.f90

@@ -0,0 +1,4 @@
+subroutine f()
+real :: var = 0.0
+save
+end subroutine

tests/tests.toml

@@ -3403,6 +3403,10 @@ asr = true
 filename = "save2.f90"
 asr = true
 
+[[test]]
+filename = "save3.f90"
+asr = true
+
 [[test]]
 filename = "../integration_tests/c_ptr_02.f90"
 asr = true
@@ -4072,4 +4076,4 @@ asr = true
 
 [[test]]
 filename = "errors/intrinsics11.f90"
-asr = true
+asr = true