Changeset 13481af0

Timestamp:

Jul 2, 2026, 5:07:05 PM (2 days ago)

Author:

Peter A. Buhr <pabuhr@…>

Branches:

master

Children:

7886a92f

Parents:

16d862d

Message:

remove addDataSectionAttribute hack and handle dynamic initialization of const definitions by removing the const after resolution

Location:

src/InitTweak

Files:

• FixGlobalInit.cpp (modified) (5 diffs)
• FixInit.cpp (modified) (1 diff)
• InitTweak.cpp (modified) (2 diffs)
• InitTweak.hpp (modified) (2 diffs)

src/InitTweak/FixGlobalInit.cpp

@@ -10 +10 @@
 // Created On       : Mon May 04 15:14:56 2016
 // Last Modified By : Peter A. Buhr
-// Last Modified On : Fri Dec 13 23:41:10 2019
-// Update Count     : 19
+// Last Modified On : Thu Jul  2 16:39:52 2026
+// Update Count     : 35
 //
 
 #include "FixGlobalInit.hpp"
 
+#include <set>
 #include <cassert>                 // for assert
 #include <stddef.h>                // for NULL
@@ -40 +41 @@
         void previsit(const ast::TypeDecl *) { visit_children = false; }
 
+        bool pass = false;
         std::list< ast::ptr<ast::Stmt> > initStmts;
         std::list< ast::ptr<ast::Stmt> > destroyStmts;
+        std::set< std::string > constDeclsMnames;
 };
 
@@ -47 +50 @@
         auto mutDecl = mutate(objDecl);
         assertf(mutDecl == objDecl, "Global object decl must be unique");
-        auto ctorInit = objDecl->init.as<ast::ConstructorInit>();
-        if ( nullptr == ctorInit ) return;
+        if ( ! pass ) {                                                                         // pass 1
+                auto ctorInit = objDecl->init.as<ast::ConstructorInit>();
+                if ( nullptr == ctorInit ) return;
 
-        // a decision should have been made by the resolver, so ctor and init are not both non-NULL
-        assert( !ctorInit->ctor || !ctorInit->init );
+                // a decision should have been made by the resolver, so ctor and init are not both non-NULL
+                assert( !ctorInit->ctor || !ctorInit->init );
 
-        const ast::Stmt * dtor = ctorInit->dtor;
-        if ( dtor && !isIntrinsicSingleArgCallStmt( dtor ) ) {
-                // don't need to call intrinsic dtor, because it does nothing, but
-                // non-intrinsic dtors must be called
-                destroyStmts.push_front( dtor );
-        } // if
-        if ( const ast::Stmt * ctor = ctorInit->ctor ) {
-                addDataSectionAttribute(mutDecl);
-                initStmts.push_back( ctor );
-                mutDecl->init = nullptr;
-        } else if ( const ast::Init * init = ctorInit->init ) {
-                mutDecl->init = init;
-        } else {
-                // no constructor and no initializer, which is okay
-                mutDecl->init = nullptr;
+                const ast::Stmt * dtor = ctorInit->dtor;
+                if ( dtor && !isIntrinsicSingleArgCallStmt( dtor ) ) {
+                        // don't need to call intrinsic dtor, because it does nothing, but
+                        // non-intrinsic dtors must be called
+                        destroyStmts.push_front( dtor );
+                } // if
+                if ( const ast::Stmt * ctor = ctorInit->ctor ) {
+                        if ( mutDecl->type->is_const() ) {
+                                // Store names of all declarations with const qualifier and initializer for second pass.
+                                constDeclsMnames.emplace( mutDecl->mangleName );
+                        }
+                        initStmts.push_back( ctor );
+                        mutDecl->init = nullptr;
+                } else if ( const ast::Init * init = ctorInit->init ) {
+                        mutDecl->init = init;
+                } else {
+                        // no constructor and no initializer, which is okay
+                        mutDecl->init = nullptr;
+                }
+        } else {                                                                                // pass 2
+                // Remove const qualifier from matching names, covering all forward declaration(s) and definition.
+                if ( constDeclsMnames.find( objDecl->mangleName ) != constDeclsMnames.end() ) {
+                        ast::Type * fred = const_cast<ast::Type *>(mutDecl->get_type());
+                        fred->set_const( false );
+                } // if
         }
 }
@@ -75 +89 @@
 void fixGlobalInit(ast::TranslationUnit & translationUnit, bool inLibrary) {
         ast::Pass<GlobalFixer> fixer;
-        accept_all(translationUnit, fixer);
+
+        // First pass fixes global initialization.
+        accept_all( translationUnit, fixer );
 
         // Say these magic declarations come at the end of the file.
@@ -103 +119 @@
                 translationUnit.decls.emplace_back(destroyFunction);
         } // if
+
+        fixer.core.pass = ! fixer.core.pass;
+        // Second pass, removes const qualifiers so declarations appear in mutable .data section.
+        // Note, the resolver has already checked for const-ness, so C only has to get the initialization correct.
+        accept_all(translationUnit, fixer);
 }
 

src/InitTweak/FixInit.cpp

@@ -816 +816 @@
         if ( const ast::Stmt * ctor = ctorInit->ctor ) {
                 if ( objDecl->storage.is_static ) {
-                        addDataSectionAttribute(objDecl);
+                        // Remove const qualifier from definition and there can be no forward declarations.
+                        if ( objDecl->type->is_const() ) {
+                                ast::Type * fred = const_cast<ast::Type *>(objDecl->get_type());
+                                fred->set_const( false );
+                        }
                         // originally wanted to take advantage of gcc nested functions, but
                         // we get memory errors with this approach. To remedy this, the static

src/InitTweak/InitTweak.cpp

@@ -9 +9 @@
 // Author           : Rob Schluntz
 // Created On       : Fri May 13 11:26:36 2016
-// Last Modified By : Andrew Beach
-// Last Modified On : Wed Sep 22  9:50:00 2022
-// Update Count     : 21
+// Last Modified By : Peter A. Buhr
+// Last Modified On : Thu Jul  2 16:47:11 2026
+// Update Count     : 44
 //
 
@@ -428 +428 @@
 }
 
-#if defined( __x86_64 ) || defined( __i386 ) // assembler comment to prevent assembler warning message
-        #define ASM_COMMENT "#"
-#else // defined( __ARM_ARCH )
-        #define ASM_COMMENT "//"
-#endif
-static const char * const data_section =  ".data" ASM_COMMENT;
-static const char * const tlsd_section = ".tdata" ASM_COMMENT;
-
-void addDataSectionAttribute( ast::ObjectDecl * objDecl ) {
-        const bool is_tls = objDecl->storage.is_threadlocal_any();
-        const char * section = is_tls ? tlsd_section : data_section;
-        objDecl->attributes.push_back(new ast::Attribute("section", {
-                ast::ConstantExpr::from_string(objDecl->location, section)
-        }));
-}
-
 InitExpander::InitExpander( const ast::Init * init )
 : expander( new InitImpl{ init } ), crnt(), indices() {}

src/InitTweak/InitTweak.hpp

@@ -9 +9 @@
 // Author           : Rob Schluntz
 // Created On       : Fri May 13 11:26:36 2016
-// Last Modified By : Andrew Beach
-// Last Modified On : Wed Sep 22  9:21:00 2022
-// Update Count     : 9
+// Last Modified By : Peter A. Buhr
+// Last Modified On : Thu Jul  2 16:45:44 2026
+// Update Count     : 12
 //
 
@@ -69 +69 @@
 bool isConstExpr( const ast::Init * init );
 
-/// Modifies objDecl to have:
-///    __attribute__((section (".data#")))
-/// which makes gcc put the declared variable in the data section,
-/// which is helpful for global constants on newer gcc versions,
-/// so that CFA's generated initialization won't segfault when writing it via a const cast.
-/// The trailing # is an injected assembly comment, to suppress the "a" in
-///    .section .data,"a"
-///    .section .data#,"a"
-/// to avoid assembler warning "ignoring changed section attributes for .data"
-void addDataSectionAttribute( ast::ObjectDecl * objDecl );
-
 class InitExpander final {
 public: