Implicitely inject extern crate core

gcc/rust/ast/rust-ast.cc

@@ -235,6 +235,14 @@ Crate::as_string () const
   return str + "\n";
 }
 
+void
+Crate::inject_extern_crate (std::string name)
+{
+  items.push_back (std::make_unique<AST::ExternCrate> (
+    AST::ExternCrate (name, AST::Visibility::create_public (UNKNOWN_LOCATION),
+		      {}, UNKNOWN_LOCATION)));
+}
+
 std::string
 Attribute::as_string () const
 {

gcc/rust/ast/rust-ast.h

@@ -2116,6 +2116,8 @@ struct Crate : public GlobContainer
     // TODO: is this the best way to do this?
   }
 
+  void inject_extern_crate (std::string name);
+
   NodeId get_node_id () const { return node_id; }
   const std::vector<Attribute> &get_inner_attrs () const { return inner_attrs; }
   std::vector<Attribute> &get_inner_attrs () { return inner_attrs; }

gcc/rust/rust-session-manager.cc

@@ -162,6 +162,16 @@ validate_crate_name (const std::string &crate_name, Error &error)
   return true;
 }
 
+static bool
+has_attribute (AST::Crate crate, std::string attribute)
+{
+  auto &crate_attrs = crate.get_inner_attrs ();
+  auto has_attr = [&attribute] (AST::Attribute &attr) {
+    return attr.as_string () == attribute;
+  };
+  return std::any_of (crate_attrs.begin (), crate_attrs.end (), has_attr);
+}
+
 void
 Session::init ()
 {
@@ -658,6 +668,11 @@ Session::compile_crate (const char *filename)
 
   Analysis::AttributeChecker ().go (parsed_crate);
 
+  if (!has_attribute (parsed_crate, std::string (Values::Attributes::NO_CORE)))
+    {
+      parsed_crate.inject_extern_crate ("core");
+    }
+
   if (last_step == CompileOptions::CompileStep::Expansion)
     return;
 

gcc/rust/util/rust-attribute-values.h

@@ -37,6 +37,7 @@ class Attributes
   static constexpr auto &MUST_USE = "must_use";
   static constexpr auto &LANG = "lang";
   static constexpr auto &LINK_NAME = "link_name";
+  static constexpr auto &NO_CORE = "no_core";
   static constexpr auto &LINK_SECTION = "link_section";
   static constexpr auto &NO_MANGLE = "no_mangle";
   static constexpr auto &EXPORT_NAME = "export_name";

gcc/testsuite/rust/borrowck/position_dependant_outlives.rs

@@ -1,4 +1,7 @@
 // { dg-additional-options "-frust-compile-until=compilation -frust-borrowcheck" }
+#![feature(no_core)]
+#![no_core]
+
 
 pub fn position_dependent_outlives<'a>(x: &'a mut i32, cond: bool) -> &'a mut i32 {
     let y = &mut *x;

gcc/testsuite/rust/borrowck/reference.rs

@@ -1,5 +1,8 @@
 // { dg-additional-options "-frust-compile-until=compilation -frust-borrowcheck -fdiagnostics-show-caret -fdiagnostics-show-line-numbers" }
 // { dg-enable-nn-line-numbers "" }
+#![feature(no_core)]
+#![no_core]
+
 
 #![feature(lang_items)]
 #[lang = "sized"]

gcc/testsuite/rust/borrowck/return_ref_to_local.rs

@@ -1,5 +1,8 @@
 // { dg-additional-options "-frust-compile-until=compilation -frust-borrowcheck -fdiagnostics-show-caret -fdiagnostics-show-line-numbers" }
 // { dg-enable-nn-line-numbers "" }
+#![feature(no_core)]
+#![no_core]
+
 
 pub fn return_ref_to_local() -> &'static i32 {
     let x = 0;

gcc/testsuite/rust/borrowck/subset.rs

@@ -1,5 +1,8 @@
 // { dg-additional-options "-frust-compile-until=compilation -frust-borrowcheck -fdiagnostics-show-caret -fdiagnostics-show-line-numbers" }
 // { dg-enable-nn-line-numbers "" }
+#![feature(no_core)]
+#![no_core]
+
 
 fn missing_subset<'a, 'b>(x: &'a u32, y: &'b u32) -> &'a u32 {
     // { dg-error "subset error, some lifetime constraints need to be added" "" { target *-*-* } .-1 }

gcc/testsuite/rust/borrowck/test_move.rs

@@ -1,5 +1,8 @@
 // { dg-additional-options "-frust-compile-until=compilation -frust-borrowcheck -fdiagnostics-show-caret -fdiagnostics-show-line-numbers" }
 // { dg-enable-nn-line-numbers "" }
+#![feature(no_core)]
+#![no_core]
+
 
 fn test_move() {
     struct A {

gcc/testsuite/rust/borrowck/test_move_behind_reference.rs

@@ -1,4 +1,7 @@
 // { dg-additional-options "-frust-compile-until=compilation -frust-borrowcheck" }
+#![feature(no_core)]
+#![no_core]
+
 fn test_move_behind_reference() {
     // { dg-error "Cannot move from behind a reference." "" { target *-*-* } .-1 }
     struct A {

gcc/testsuite/rust/borrowck/test_move_conditional.rs

@@ -1,5 +1,8 @@
 // { dg-additional-options "-frust-compile-until=compilation -frust-borrowcheck -fdiagnostics-show-caret -fdiagnostics-show-line-numbers" }
 // { dg-enable-nn-line-numbers "" }
+#![feature(no_core)]
+#![no_core]
+
 
 fn test_move_conditional(b1: bool, b2:bool) {
     struct A {

gcc/testsuite/rust/borrowck/tmp.rs

@@ -1,5 +1,8 @@
 // { dg-additional-options "-frust-compile-until=compilation -frust-borrowcheck -fdiagnostics-show-caret -fdiagnostics-show-line-numbers" }
 // { dg-enable-nn-line-numbers "" }
+#![feature(no_core)]
+#![no_core]
+
 
 #![feature(lang_items)]
 #[lang = "sized"]

gcc/testsuite/rust/borrowck/use_while_mut.rs

@@ -1,5 +1,8 @@
 // { dg-additional-options "-frust-compile-until=compilation -frust-borrowcheck -fdiagnostics-show-caret -fdiagnostics-show-line-numbers" }
 // { dg-enable-nn-line-numbers "" }
+#![feature(no_core)]
+#![no_core]
+
 
 pub fn use_while_mut() {
     let mut x = 0;

gcc/testsuite/rust/borrowck/use_while_mut_fr.rs

@@ -1,5 +1,8 @@
 // { dg-additional-options "-frust-compile-until=compilation -frust-borrowcheck -fdiagnostics-show-caret -fdiagnostics-show-line-numbers" }
 // { dg-enable-nn-line-numbers "" }
+#![feature(no_core)]
+#![no_core]
+
 pub fn use_while_mut_fr(x: &mut i32) -> &mut i32 {
     let y = &mut *x;
     let z = x; //~ ERROR

gcc/testsuite/rust/borrowck/well_formed_function_inputs.rs

@@ -1,5 +1,8 @@
 // { dg-additional-options "-frust-compile-until=compilation -frust-borrowcheck -fdiagnostics-show-caret -fdiagnostics-show-line-numbers" }
 // { dg-enable-nn-line-numbers "" }
+#![feature(no_core)]
+#![no_core]
+
 
 fn foo<'a, 'b>(p: &'b &'a mut usize) -> &'b&'a mut usize {
     p

gcc/testsuite/rust/compile/abi-options1.rs

@@ -1,3 +1,6 @@
+#![feature(no_core)]
+#![no_core]
+
 extern "foobar" {
     // { dg-error "invalid ABI: found .foobar." "" { target *-*-* } .-1 }
     fn printf(s: *const i8, ...);

gcc/testsuite/rust/compile/abi-vardaic.rs

@@ -1,4 +1,7 @@
 // https://doc.rust-lang.org/error_codes/E0045.html
+#![feature(no_core)]
+#![no_core]
+
 #![allow(unused)]
 fn main() {
     extern "Rust" {

gcc/testsuite/rust/compile/additional-trait-bounds1.rs

@@ -1,3 +1,6 @@
+#![feature(no_core)]
+#![no_core]
+
 #![feature(optin_builtin_traits, lang_items)]
 
 pub unsafe auto trait Send {}

gcc/testsuite/rust/compile/additional-trait-bounds2.rs

@@ -1,3 +1,6 @@
+#![feature(no_core)]
+#![no_core]
+
 #![feature(optin_builtin_traits, lang_items)]
 
 pub unsafe auto trait Send {}

gcc/testsuite/rust/compile/additional-trait-bounds2nr2.rs

@@ -1,3 +1,6 @@
+#![feature(no_core)]
+#![no_core]
+
 #![feature(optin_builtin_traits, lang_items)]
 
 pub unsafe auto trait Send {}

gcc/testsuite/rust/compile/all-cast.rs

@@ -1,3 +1,6 @@
+#![feature(no_core)]
+#![no_core]
+
 fn main() {
     let x = 5;
     let x_is_nonzero = x as bool; // { dg-error "cannot cast .<integer>. as .bool." }

gcc/testsuite/rust/compile/array3.rs

@@ -1,3 +1,6 @@
+#![feature(no_core)]
+#![no_core]
+
 fn foo(state: &mut [u32; 16], a: usize) {
     // { dg-warning "function is never used: .foo." "" { target *-*-* } .-1 }
     state[a] = 1;

gcc/testsuite/rust/compile/array4.rs

@@ -1,3 +1,6 @@
+#![feature(no_core)]
+#![no_core]
+
 pub fn foo() {
     [0, 1, 2][1];
 }

gcc/testsuite/rust/compile/array_empty_list.rs

@@ -1,3 +1,6 @@
+#![feature(no_core)]
+#![no_core]
+
 fn main() {
     let arr = [];
     // { dg-error "type annotations needed" "" { target *-*-* } .-1 }

gcc/testsuite/rust/compile/arrays1.rs

@@ -1,3 +1,6 @@
+#![feature(no_core)]
+#![no_core]
+
 fn main() {
     let xs: [i32; 5] = [1, 2, 3, 4, 5];
     let a: bool = xs[0]; // { dg-error "mismatched types, expected .bool. but got .i32." }

gcc/testsuite/rust/compile/arrays2.rs

@@ -1,3 +1,6 @@
+#![feature(no_core)]
+#![no_core]
+
 fn main() {
     let array: [i32; 5] = [1, 2, 3];
     // { dg-error "mismatched types, expected ..i32; 5.. but got ...integer.; 3.. .E0308." "" { target *-*-* } .-1 }

gcc/testsuite/rust/compile/assume.rs

@@ -1,3 +1,6 @@
+#![feature(no_core)]
+#![no_core]
+
 #![feature(intrinsics)]
 
 mod intrinsics {

gcc/testsuite/rust/compile/attr-macro.rs

@@ -1,3 +1,6 @@
+#![feature(no_core)]
+#![no_core]
+
 macro_rules! foo {
     () => { #[cfg(all())] 12 }
 }

gcc/testsuite/rust/compile/attr-mismatch-crate-name.rs

@@ -1,4 +1,7 @@
 // { dg-additional-options "-fdump-tree-gimple" }
+#![feature(no_core)]
+#![no_core]
+
 #![crate_name = "specified_name"]
 // { dg-final { scan-tree-dump-times {specified_name::main} 1 gimple } }
 fn main() {}

gcc/testsuite/rust/compile/attr_cold.rs

@@ -1,4 +1,7 @@
 // { dg-additional-options "-fdump-tree-gimple" }
+#![feature(no_core)]
+#![no_core]
+
 #[cold]
 fn cold_function() -> i32 {
     42

gcc/testsuite/rust/compile/attr_deprecated.rs

@@ -1,3 +1,6 @@
+#![feature(no_core)]
+#![no_core]
+
 #[deprecated(since="1.0", note="do not use this function")]
 fn test1() {}
 

gcc/testsuite/rust/compile/attr_deprecated_2.rs

@@ -1,3 +1,6 @@
+#![feature(no_core)]
+#![no_core]
+
 #[deprecated(since="1.0")]
 fn test1() {}
 

gcc/testsuite/rust/compile/attr_malformed_doc.rs

@@ -1,3 +1,6 @@
+#![feature(no_core)]
+#![no_core]
+
 // { dg-error "valid forms for the attribute are ...doc.hidden.inline....... and ...doc = . string ..." "" { target *-*-* } .+1 }
 #[doc]
 trait MyTrait {}

gcc/testsuite/rust/compile/attr_malformed_path.rs

@@ -1,3 +1,6 @@
+#![feature(no_core)]
+#![no_core]
+
 #[cfg_attr(target_arch = "x86_64", path = (target_arch = "x86",    path = "x86.rs"))]
 mod imp {}
 // { dg-error "malformed .path. attribute input" "" { target *-*-* } .-2 }

gcc/testsuite/rust/compile/auto_trait.rs

@@ -1 +1,4 @@
+#![feature(no_core)]
+#![no_core]
+
 auto trait Valid {} // { dg-error "auto traits are experimental and possibly buggy" }

gcc/testsuite/rust/compile/auto_trait_invalid.rs

@@ -1,4 +1,7 @@
 // #![feature(auto_traits)] // not present in Rust 1.49 yet
+#![feature(no_core)]
+#![no_core]
+
 
 #![feature(optin_builtin_traits)]
 

gcc/testsuite/rust/compile/auto_trait_super_trait.rs

@@ -1,3 +1,6 @@
+#![feature(no_core)]
+#![no_core]
+
 #![feature(optin_builtin_traits)]
 trait Cold {}
 

gcc/testsuite/rust/compile/auto_trait_valid.rs

@@ -1,4 +1,7 @@
 // #![feature(auto_traits)] // not present in Rust 1.49 yet
+#![feature(no_core)]
+#![no_core]
+
 
 #![feature(optin_builtin_traits)]
 

gcc/testsuite/rust/compile/auto_traits1.rs

@@ -1,4 +1,7 @@
 // { dg-additional-options "-frust-compile-until=typecheck" }
+#![feature(no_core)]
+#![no_core]
+
 
 #![feature(optin_builtin_traits, lang_items)]
 

gcc/testsuite/rust/compile/auto_traits2.rs

@@ -1,3 +1,6 @@
+#![feature(no_core)]
+#![no_core]
+
 #![feature(optin_builtin_traits, lang_items)]
 
 pub unsafe auto trait Send {}

gcc/testsuite/rust/compile/auto_traits4.rs

@@ -1,3 +1,6 @@
+#![feature(no_core)]
+#![no_core]
+
 #![feature(optin_builtin_traits)]
 
 unsafe auto trait Send {}

gcc/testsuite/rust/compile/bad-crate-name1.rs

@@ -1,4 +1,7 @@
 // { dg-additional-options "-frust-crate=bad+name" }
 // { dg-excess-errors "invalid crate name: ...." }
 // { dg-excess-errors "unrecognized command-line option ...." }
+#![feature(no_core)]
+#![no_core]
+
 fn main() {}

gcc/testsuite/rust/compile/bad-crate-name2.rs

@@ -1,2 +1,5 @@
+#![feature(no_core)]
+#![no_core]
+
 #![crate_name = "😅"] // { dg-error "invalid character ...." "" }
 fn main() {}

gcc/testsuite/rust/compile/bad-rpit1.rs

@@ -1,3 +1,6 @@
+#![feature(no_core)]
+#![no_core]
+
 #![feature(lang_items)]
 #[lang = "sized"]
 trait Sized {}

gcc/testsuite/rust/compile/bad=file-name.rs

@@ -1,4 +1,7 @@
 // { dg-additional-options "-fdump-tree-gimple -frust-crate=good_name" }
+#![feature(no_core)]
+#![no_core]
+
 pub fn does_nothing() {}
 fn main() {
     does_nothing()

gcc/testsuite/rust/compile/bad_as_bool_char.rs

@@ -1,3 +1,6 @@
+#![feature(no_core)]
+#![no_core]
+
 pub fn main ()
 {
   let t = true;

gcc/testsuite/rust/compile/bad_file_name.txt.rs

@@ -1,3 +1,6 @@
 // { dg-excess-errors "invalid crate name: ...." }
 // { dg-bogus "unrecognized command-line option ...." }
+#![feature(no_core)]
+#![no_core]
+
 fn main() {}

gcc/testsuite/rust/compile/bad_inner_doc.rs

@@ -1,3 +1,6 @@
+#![feature(no_core)]
+#![no_core]
+
 pub fn main ()
 {
   //! inner doc allowed