Cleanup fix for global initialization (#93)

* Cleanup fix for global initialization
* Remove linker script hack
* Use v0 symbol mangling
* Fix warnings

Author: antoyo

config.sh

@@ -38,7 +38,7 @@ if [[ "$HOST_TRIPLE" != "$TARGET_TRIPLE" ]]; then
    fi
 fi
 
-export RUSTFLAGS="$linker -Cpanic=abort -Cdebuginfo=2 -Clto=off -Zpanic-abort-tests -Zcodegen-backend=$(pwd)/target/${CHANNEL:-debug}/librustc_codegen_gcc.$dylib_ext --sysroot $(pwd)/build_sysroot/sysroot"
+export RUSTFLAGS="$linker -Cpanic=abort -Zsymbol-mangling-version=v0 -Cdebuginfo=2 -Clto=off -Zpanic-abort-tests -Zcodegen-backend=$(pwd)/target/${CHANNEL:-debug}/librustc_codegen_gcc.$dylib_ext --sysroot $(pwd)/build_sysroot/sysroot"
 
 # FIXME(antoyo): remove once the atomic shim is gone
 if [[ `uname` == 'Darwin' ]]; then

src/common.rs

@@ -43,10 +43,8 @@ impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
         // TODO(antoyo): handle non-null-terminated strings.
         let string = self.context.new_string_literal(&*string);
         let sym = self.generate_local_symbol_name("str");
-        // NOTE: TLS is always off for a string litteral.
-        // NOTE: string litterals do not have a link section.
         let global = self.declare_private_global(&sym, self.val_ty(string));
-        global.global_set_initializer_value(string); // TODO: only set if not imported?
+        global.global_set_initializer_value(string);
         global
         // TODO(antoyo): set linkage.
     }

src/lib.rs

@@ -63,7 +63,7 @@ use rustc_errors::{ErrorReported, Handler};
 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
 use rustc_middle::middle::cstore::EncodedMetadata;
 use rustc_middle::ty::TyCtxt;
-use rustc_session::config::{CrateType, Lto, OptLevel, OutputFilenames};
+use rustc_session::config::{Lto, OptLevel, OutputFilenames};
 use rustc_session::Session;
 use rustc_span::Symbol;
 use rustc_span::fatal_error::FatalError;
@@ -106,16 +106,8 @@ impl CodegenBackend for GccCodegenBackend {
         Ok((codegen_results, work_products))
     }
 
-    fn link(&self, sess: &Session, mut codegen_results: CodegenResults, outputs: &OutputFilenames) -> Result<(), ErrorReported> {
+    fn link(&self, sess: &Session, codegen_results: CodegenResults, outputs: &OutputFilenames) -> Result<(), ErrorReported> {
         use rustc_codegen_ssa::back::link::link_binary;
-        if let Some(symbols) = codegen_results.crate_info.exported_symbols.get_mut(&CrateType::Dylib) {
-            // TODO:(antoyo): remove when global initializer work without calling a function at runtime.
-            // HACK: since this codegen add some symbols (e.g. __gccGlobalCrateInit) and the UI
-            // tests load libstd.so as a dynamic library, and rustc use a version-script to specify
-            // the symbols visibility, we add * to export all symbols.
-            // It seems other symbols from libstd/libcore are causing some issues here as well.
-            symbols.push("*".to_string());
-        }
 
         link_binary::<crate::archive::ArArchiveBuilder<'_>>(
             sess,

test.sh

@@ -171,7 +171,7 @@ git checkout src/test/ui/type-alias-impl-trait/auxiliary/cross_crate_ice.rs
 git checkout src/test/ui/type-alias-impl-trait/auxiliary/cross_crate_ice2.rs
 rm src/test/ui/llvm-asm/llvm-asm-in-out-operand.rs || true # TODO(antoyo): Enable back this test if I ever implement the llvm_asm! macro.
 
-RUSTC_ARGS="-Zpanic-abort-tests -Zcodegen-backend="$(pwd)"/../target/"$CHANNEL"/librustc_codegen_gcc."$dylib_ext" --sysroot "$(pwd)"/../build_sysroot/sysroot -Cpanic=abort"
+RUSTC_ARGS="-Zpanic-abort-tests -Zsymbol-mangling-version=v0 -Zcodegen-backend="$(pwd)"/../target/"$CHANNEL"/librustc_codegen_gcc."$dylib_ext" --sysroot "$(pwd)"/../build_sysroot/sysroot -Cpanic=abort"
 
 echo "[TEST] rustc test suite"
 COMPILETEST_FORCE_STAGE0=1 ./x.py test --run always --stage 0 src/test/ui/ --rustc-args "$RUSTC_ARGS"