trans: Make names of internal symbols independent of CGU translation order

src/librustc_trans/common.rs

@@ -799,9 +799,7 @@ pub fn C_cstr(cx: &CrateContext, s: InternedString, null_terminated: bool) -> Va
                                                 s.as_ptr() as *const c_char,
                                                 s.len() as c_uint,
                                                 !null_terminated as Bool);
-
-        let gsym = token::gensym("str");
-        let sym = format!("str{}", gsym.0);
+        let sym = cx.generate_local_symbol_name("str");
         let g = declare::define_global(cx, &sym[..], val_ty(sc)).unwrap_or_else(||{
             bug!("symbol `{}` is already defined", sym);
         });

src/librustc_trans/consts.rs

@@ -30,7 +30,6 @@ use rustc::hir;
 use std::ffi::{CStr, CString};
 use syntax::ast;
 use syntax::attr;
-use syntax::parse::token;
 
 pub fn ptrcast(val: ValueRef, ty: Type) -> ValueRef {
     unsafe {
@@ -44,10 +43,7 @@ pub fn addr_of_mut(ccx: &CrateContext,
                    kind: &str)
                     -> ValueRef {
     unsafe {
-        // FIXME: this totally needs a better name generation scheme, perhaps a simple global
-        // counter? Also most other uses of gensym in trans.
-        let gsym = token::gensym("_");
-        let name = format!("{}{}", kind, gsym.0);
+        let name = ccx.generate_local_symbol_name(kind);
         let gv = declare::define_global(ccx, &name[..], val_ty(cv)).unwrap_or_else(||{
             bug!("symbol `{}` is already defined", name);
         });

src/librustc_trans/context.rs

@@ -166,6 +166,9 @@ pub struct LocalCrateContext<'tcx> {
     type_of_depth: Cell<usize>,
 
     symbol_map: Rc<SymbolMap<'tcx>>,
+
+    /// A counter that is used for generating local symbol names
+    local_gen_sym_counter: Cell<usize>,
 }
 
 // Implement DepTrackingMapConfig for `trait_cache`
@@ -688,6 +691,7 @@ impl<'tcx> LocalCrateContext<'tcx> {
                 n_llvm_insns: Cell::new(0),
                 type_of_depth: Cell::new(0),
                 symbol_map: symbol_map,
+                local_gen_sym_counter: Cell::new(0),
             };
 
             let (int_type, opaque_vec_type, str_slice_ty, mut local_ccx) = {
@@ -1021,6 +1025,16 @@ impl<'b, 'tcx> CrateContext<'b, 'tcx> {
     pub fn empty_substs_for_def_id(&self, item_def_id: DefId) -> &'tcx Substs<'tcx> {
         self.shared().empty_substs_for_def_id(item_def_id)
     }
+
+    /// Generate a new symbol name with the given prefix. This symbol name must
+    /// only be used for definitions with `internal` or `private` linkage.
+    pub fn generate_local_symbol_name(&self, prefix: &str) -> String {
+        let idx = self.local().local_gen_sym_counter.get();
+        self.local().local_gen_sym_counter.set(idx + 1);
+        // Include a '.' character, so there can be no accidental conflicts with
+        // user defined names
+        format!("{}.{}", prefix, idx)
+    }
 }
 
 pub struct TypeOfDepthLock<'a, 'tcx: 'a>(&'a LocalCrateContext<'tcx>);

src/test/codegen/consts.rs

@@ -19,12 +19,12 @@
 // CHECK: @STATIC = {{.*}}, align 4
 
 // This checks the constants from inline_enum_const
-// CHECK: @ref{{[0-9]+}} = {{.*}}, align 2
+// CHECK: @ref.{{[0-9]+}} = {{.*}}, align 2
 
 // This checks the constants from {low,high}_align_const, they share the same
 // constant, but the alignment differs, so the higher one should be used
-// CHECK: [[LOW_HIGH:@ref[0-9]+]] = {{.*}}, align 4
-// CHECK: [[LOW_HIGH_REF:@const[0-9]+]] = {{.*}} [[LOW_HIGH]]
+// CHECK: [[LOW_HIGH:@ref.[0-9]+]] = {{.*}}, align 4
+// CHECK: [[LOW_HIGH_REF:@const.[0-9]+]] = {{.*}} [[LOW_HIGH]]
 
 #[derive(Copy, Clone)]
 

src/test/run-make/symbols-are-reasonable/Makefile

@@ -1,7 +1,7 @@
 -include ../tools.mk
 
 # check that the compile generated symbols for strings, binaries,
-# vtables, etc. have semisane names (e.g. `str1234`); it's relatively
+# vtables, etc. have semisane names (e.g. `str.1234`); it's relatively
 # easy to accidentally modify the compiler internals to make them
 # become things like `str"str"(1234)`.
 
@@ -10,6 +10,6 @@ OUT=$(TMPDIR)/lib.s
 all:
 	$(RUSTC) lib.rs --emit=asm --crate-type=staticlib
 	# just check for symbol declarations with the names we're expecting.
-	grep 'str[0-9][0-9]*:' $(OUT)
-	grep 'byte_str[0-9][0-9]*:' $(OUT)
-	grep 'vtable[0-9][0-9]*' $(OUT)
+	grep 'str.[0-9][0-9]*:' $(OUT)
+	grep 'byte_str.[0-9][0-9]*:' $(OUT)
+	grep 'vtable.[0-9][0-9]*' $(OUT)