Correctly import foreign statics

Previously foreign statics would actually cause a local static to be
defined and exported. This issue was found because std::env::vars() was
found to return no env vars despite many being defined. This was caused
by libstd importing environ as foreign static. The accidental definition
of environ caused libstd to read a null pointer which was interpreted as
there being no environment variables at all.

Also fix tests. STDOUT is not defined by libc. The correct name is stdout.
This previously worked as STDOUT was incorrectly defined as null pointer
during codegen.

Author: bjorn3

src/consts.rs

@@ -1,4 +1,4 @@
-use gccjit::{LValue, RValue, ToRValue, Type};
+use gccjit::{GlobalKind, LValue, RValue, ToRValue, Type};
 use rustc_codegen_ssa::traits::{BaseTypeMethods, ConstMethods, DerivedTypeMethods, StaticMethods};
 use rustc_hir as hir;
 use rustc_hir::Node;
@@ -218,7 +218,13 @@ impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
                         }
 
                         let is_tls = fn_attrs.flags.contains(CodegenFnAttrFlags::THREAD_LOCAL);
-                        let global = self.declare_global(&sym, llty, is_tls, fn_attrs.link_section);
+                        let global = self.declare_global(
+                            &sym,
+                            llty,
+                            GlobalKind::Exported,
+                            is_tls,
+                            fn_attrs.link_section,
+                        );
 
                         if !self.tcx.is_reachable_non_generic(def_id) {
                             // TODO(antoyo): set visibility.
@@ -389,6 +395,6 @@ fn check_and_apply_linkage<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, attrs: &Codeg
         // don't do this then linker errors can be generated where the linker
         // complains that one object files has a thread local version of the
         // symbol and another one doesn't.
-        cx.declare_global(&sym, llty, is_tls, attrs.link_section)
+        cx.declare_global(&sym, llty, GlobalKind::Imported, is_tls, attrs.link_section)
     }
 }

src/declare.rs

@@ -22,7 +22,7 @@ impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
             global
         }
         else {
-            self.declare_global(name, ty, is_tls, link_section)
+            self.declare_global(name, ty, GlobalKind::Exported, is_tls, link_section)
         }
     }
 
@@ -47,8 +47,8 @@ impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
         unsafe { std::mem::transmute(func) }
     }*/
 
-    pub fn declare_global(&self, name: &str, ty: Type<'gcc>, is_tls: bool, link_section: Option<Symbol>) -> LValue<'gcc> {
-        let global = self.context.new_global(None, GlobalKind::Exported, ty, name);
+    pub fn declare_global(&self, name: &str, ty: Type<'gcc>, global_kind: GlobalKind, is_tls: bool, link_section: Option<Symbol>) -> LValue<'gcc> {
+        let global = self.context.new_global(None, global_kind, ty, name);
         if is_tls {
             global.set_tls_model(self.tls_model);
         }

tests/run/assign.rs

@@ -51,7 +51,7 @@ mod libc {
         pub fn fflush(stream: *mut i32) -> i32;
         pub fn printf(format: *const i8, ...) -> i32;
 
-        pub static STDOUT: *mut i32;
+        pub static stdout: *mut i32;
     }
 }
 
@@ -67,7 +67,7 @@ mod intrinsics {
 pub fn panic(_msg: &str) -> ! {
     unsafe {
         libc::puts("Panicking\0" as *const str as *const u8);
-        libc::fflush(libc::STDOUT);
+        libc::fflush(libc::stdout);
         intrinsics::abort();
     }
 }

tests/run/int_overflow.rs

@@ -49,7 +49,7 @@ mod libc {
         pub fn puts(s: *const u8) -> i32;
         pub fn fflush(stream: *mut i32) -> i32;
 
-        pub static STDOUT: *mut i32;
+        pub static stdout: *mut i32;
     }
 }
 
@@ -65,7 +65,7 @@ mod intrinsics {
 pub fn panic(_msg: &str) -> ! {
     unsafe {
         libc::puts("Panicking\0" as *const str as *const u8);
-        libc::fflush(libc::STDOUT);
+        libc::fflush(libc::stdout);
         intrinsics::abort();
     }
 }

tests/run/mut_ref.rs

@@ -53,7 +53,7 @@ mod libc {
         pub fn fflush(stream: *mut i32) -> i32;
         pub fn printf(format: *const i8, ...) -> i32;
 
-        pub static STDOUT: *mut i32;
+        pub static stdout: *mut i32;
     }
 }
 
@@ -69,7 +69,7 @@ mod intrinsics {
 pub fn panic(_msg: &str) -> ! {
     unsafe {
         libc::puts("Panicking\0" as *const str as *const u8);
-        libc::fflush(libc::STDOUT);
+        libc::fflush(libc::stdout);
         intrinsics::abort();
     }
 }

tests/run/operations.rs

@@ -59,7 +59,7 @@ mod libc {
         pub fn puts(s: *const u8) -> i32;
         pub fn fflush(stream: *mut i32) -> i32;
 
-        pub static STDOUT: *mut i32;
+        pub static stdout: *mut i32;
     }
 }
 
@@ -75,7 +75,7 @@ mod intrinsics {
 pub fn panic(_msg: &str) -> ! {
     unsafe {
         libc::puts("Panicking\0" as *const str as *const u8);
-        libc::fflush(libc::STDOUT);
+        libc::fflush(libc::stdout);
         intrinsics::abort();
     }
 }