Changeset d8a3073 for src/CodeGen/LinkOnce.cpp

Timestamp:

Apr 26, 2026, 5:46:08 PM (2 days ago)

Author:

Matthew Au-Yeung <mw2auyeu@…>

Branches:

stuck-waitfor-destruct

Parents:

88bb0b4

git-author:

Matthew Au-Yeung <mw2auyeu@…> (04/26/26 17:44:48)

git-committer:

Matthew Au-Yeung <mw2auyeu@…> (04/26/26 17:46:08)

Message:

Set top level autogen cfa_linkonce

• Remove default static and inline
• Add pass to autogen functions in lib to have default visibility
• Add fix for union ctor with array constructor passing pointer to array instead of array itself. Previous changes brought light the compilation error.
• Note: found compilation trying to invoke union operator with array in cfa

File:

• src/CodeGen/LinkOnce.cpp (modified) (5 diffs)

src/CodeGen/LinkOnce.cpp

@@ -22 +22 @@
 #include "AST/Expr.hpp"
 #include "AST/Pass.hpp"
+#include "CompilationState.hpp"
+#include "InitTweak/InitTweak.hpp"
 
 namespace CodeGen {
@@ -33 +35 @@
 bool is_section_attribute( ast::Attribute const * attr ) {
         return "section" == attr->name;
+}
+
+bool is_visibility_attribute( ast::Attribute const * attr ) {
+        return "visibility" == attr->name;
 }
 
@@ -60 +66 @@
                 ast::Attribute * attribute = found->get_and_mutate();
                 assert( attribute->params.empty() );
-                assert( !decl->mangleName.empty() );
 
                 attribute->name = "section";
@@ -69 +74 @@
                 );
 
-                // Unconditionnaly add "visibility(default)" to anything with
-                // .gnu.linkonce visibility is a mess otherwise.
                 attributes.push_back( new ast::Attribute( "visibility", {
+                        ast::ConstantExpr::from_string( mutDecl->location, "default" )
+                } ) );
+
+                // Mark as used so GCC does not warn about unused definitions
+                // in translation units that include but don't call the function.
+                attributes.push_back( new ast::Attribute( "used" ) );
+
+                return mutDecl;
+        }
+};
+
+/// Adds visibility("default") to autogen CFA autogen function definitions so they
+/// are exported from shared libraries compiled with -fvisibility=hidden.
+struct AutogenDefaultVisibility {
+        int funcDepth = 0;
+
+        void previsit( ast::FunctionDecl const * ) {
+                funcDepth++;
+        }
+
+        ast::FunctionDecl const * postvisit( ast::FunctionDecl const * decl ) {
+                funcDepth--;
+                // Only top-level function definitions (not nested).
+                if ( funcDepth > 0 ) return decl;
+                // Only CFA-mangled, non-builtin, non-static, non-inline functions.
+                if ( !decl->linkage.is_mangled ) return decl;
+                if ( decl->linkage.is_builtin ) return decl;
+                if ( decl->storage.is_static || decl->funcSpec.is_inline ) return decl;
+
+                // Only definitions (functions with bodies).
+                if ( !decl->stmts ) return decl;
+
+                // Only constructors, destructors, and assignment operators —
+                // the functions that cfa_linkonce autogen functions call on member types.
+                if ( !InitTweak::isDefaultConstructor( decl )
+                                && !InitTweak::isCopyConstructor( decl )
+                                && !InitTweak::isDestructor( decl )
+                                && !InitTweak::isAssignment( decl ) ) return decl;
+
+                // Skip if already has a visibility attribute.
+                auto & attributes = decl->attributes;
+                auto found = std::find_if( attributes.begin(), attributes.end(),
+                                is_visibility_attribute );
+                if ( attributes.end() != found ) return decl;
+
+                auto mutDecl = mutate( decl );
+                mutDecl->attributes.push_back( new ast::Attribute( "visibility", {
                         ast::ConstantExpr::from_string( mutDecl->location, "default" )
                 } ) );
@@ -82 +132 @@
 void translateLinkOnce( ast::TranslationUnit & translationUnit ) {
         ast::Pass<LinkOnceCore>::run( translationUnit );
+
+        // When building libcfa (-cfalib), add visibility("default") to CFA
+        // function definitions so they are exported despite -fvisibility=hidden.
+        if ( buildingLibrary() ) {
+                ast::Pass<AutogenDefaultVisibility>::run( translationUnit );
+        }
 }