fix: Hide linker-defined symbols in shared libraries

libwild/src/elf.rs

@@ -628,12 +628,24 @@ impl platform::Platform for Elf {
             .section_group_end(output_section_id::FINI_ARRAY, "__fini_array_end")
             .hide();
 
-        symbols.section_end(output_section_id::TEXT, "etext");
-        symbols.section_end(output_section_id::TEXT, "_etext");
-        symbols.section_end(output_section_id::TEXT, "__etext");
+        // GNU ld doesn't emit these symbols in shared libraries, so we hide them
+        let hidden = output_kind.is_shared_object();
+        symbols
+            .section_end(output_section_id::TEXT, "etext")
+            .set_hidden(hidden);
+        symbols
+            .section_end(output_section_id::TEXT, "_etext")
+            .set_hidden(hidden);
+        symbols
+            .section_end(output_section_id::TEXT, "__etext")
+            .set_hidden(hidden);
 
-        symbols.section_end(output_section_id::BSS, "end");
-        symbols.section_end(output_section_id::BSS, "_end");
+        symbols
+            .section_end(output_section_id::BSS, "end")
+            .set_hidden(hidden);
+        symbols
+            .section_end(output_section_id::BSS, "_end")
+            .set_hidden(hidden);
         symbols.section_end(output_section_id::BSS, "__end").hide();
 
         // TODO: define the symbol only on RISC-V target
@@ -642,8 +654,12 @@ impl platform::Platform for Elf {
             crate::elf::GLOBAL_POINTER_SYMBOL_NAME,
         );
 
-        symbols.section_end(output_section_id::DATA, "edata");
-        symbols.section_end(output_section_id::DATA, "_edata");
+        symbols
+            .section_end(output_section_id::DATA, "edata")
+            .set_hidden(hidden);
+        symbols
+            .section_end(output_section_id::DATA, "_edata")
+            .set_hidden(hidden);
 
         symbols
             .section_start(output_section_id::TDATA, "__tdata_start")

libwild/src/parsing.rs

@@ -189,6 +189,11 @@ impl<'data> InternalSymDefInfo<'data> {
         self.is_hidden = true;
         self
     }
+
+    pub(crate) fn set_hidden(&mut self, hidden: bool) -> &mut Self {
+        self.is_hidden = hidden;
+        self
+    }
 }
 
 impl<'data, P: Platform> ParsedInputObject<'data, P> {

wild/tests/integration_tests.rs

@@ -161,6 +161,9 @@
 //!
 //! size=N: Type: Integer. Asserts the st_size of the symbol. Useful for verifying that
 //! size-changing relaxations (e.g. RISC-V call relaxation) were applied.
+//!
+//! binding=local|global|weak: Type: string. Asserts the binding of the symbol (STB_LOCAL,
+//! STB_GLOBAL or STB_WEAK).
 
 mod external_tests;
 
@@ -897,6 +900,8 @@ struct SymtabAssertions {
     absolute_address: Option<u64>,
 
     size: Option<u64>,
+
+    binding: Option<String>,
 }
 
 impl ExpectedSymtabEntry {
@@ -2987,6 +2992,28 @@ fn verify_symbol_assertions(
                 );
             }
         }
+
+        if let Some(expected_binding) = exp.assertions.binding.as_deref() {
+            if !matches!(expected_binding, "local" | "global" | "weak") {
+                bail!(
+                    "Invalid binding value `{expected_binding}` for symbol `{name}`. \
+                     Must be one of: local, global, weak"
+                );
+            }
+            let actual_binding = if sym.is_weak() {
+                "weak"
+            } else if sym.is_global() {
+                "global"
+            } else {
+                "local"
+            };
+            if expected_binding != actual_binding {
+                bail!(
+                    "Expected symbol `{name}` to have binding `{expected_binding}`, \
+                     but it actually had binding `{actual_binding}`"
+                );
+            }
+        }
     }
 
     let missing: Vec<&str> = missing.into_keys().collect();
@@ -3559,6 +3586,7 @@ fn integration_test(
         "linker-script-executable.c",
         "linker-script-provide.c",
         "linker-defined-provide.c",
+        "linker-defined-syms-shared.c",
         "libc-ifunc.c",
         "libc-integration.c",
         "rust-integration.rs",

wild/tests/sources/linker-defined-syms-shared.c

@@ -0,0 +1,35 @@
+// Test that linker-defined section boundary symbols are not exported to .dynsym
+// in shared objects, matching GNU ld behavior.
+// TODO: Once linker-defined symbol GC is implemented, add a variant that
+// references these symbols and asserts they appear as GLOBAL in .dynsym.
+//#LinkArgs:-shared -z now
+//#RunEnabled:false
+//#CompArgs:-fPIC
+//#DiffEnabled:false
+
+// These symbols should NOT appear in .dynsym for shared objects
+//#NoDynSym:etext
+//#NoDynSym:_etext
+//#NoDynSym:__etext
+//#NoDynSym:end
+//#NoDynSym:_end
+//#NoDynSym:edata
+//#NoDynSym:_edata
+
+// Wild keeps them in .symtab as LOCAL. GNU ld removes them entirely with
+// --gc-sections, so we only assert this for Wild.
+//#SkipLinker:ld
+//#ExpectSym:etext binding=local
+//#ExpectSym:_etext binding=local
+//#ExpectSym:__etext binding=local
+//#ExpectSym:end binding=local
+//#ExpectSym:_end binding=local
+//#ExpectSym:edata binding=local
+//#ExpectSym:_edata binding=local
+
+// data_var and bss_var ensure .data and .bss sections exist so that
+// edata, _edata, end and _end symbols are emitted by Wild.
+int data_var = 1;
+int bss_var;
+
+void foo(void) {}