codegen: change $6d$ to $u6d$

This changes a mistake introduced in rust-lang#61195 where the mangling
workaround used was incorrect.

Author: davidtwco

Diff for: src/librustc_codegen_utils/symbol_names/legacy.rs

@@ -440,7 +440,7 @@ impl fmt::Write for SymbolPrinter<'_, '_> {
                 '-' | ':' => self.path.temp_buf.push('.'),
 
                 // Avoid crashing LLVM in certain (LTO-related) situations, see #60925.
-                'm' if self.path.temp_buf.ends_with(".llv") => self.path.temp_buf.push_str("$6d$"),
+                'm' if self.path.temp_buf.ends_with(".llv") => self.path.temp_buf.push_str("$u6d$"),
 
                 // These are legal symbols
                 'a'..='z' | 'A'..='Z' | '0'..='9' | '_' | '.' | '$' => self.path.temp_buf.push(c),

Diff for: src/test/ui/symbol-names/issue-60925.legacy.stderr

@@ -1,16 +1,16 @@
-error: symbol-name(_ZN11issue_609253foo36Foo$LT$issue_60925..llv$6d$..Foo$GT$3foo17h059a991a004536adE)
+error: symbol-name(_ZN11issue_609253foo37Foo$LT$issue_60925..llv$u6d$..Foo$GT$3foo17h059a991a004536adE)
   --> $DIR/issue-60925.rs:21:9
    |
 LL |         #[rustc_symbol_name]
    |         ^^^^^^^^^^^^^^^^^^^^
 
-error: demangling(issue_60925::foo::Foo<issue_60925::llv$6d$..Foo$GT$::foo::h059a991a004536ad)
+error: demangling(issue_60925::foo::Foo<issue_60925::llv$u6d$..Foo$GT$::foo::h059a991a004536ad)
   --> $DIR/issue-60925.rs:21:9
    |
 LL |         #[rustc_symbol_name]
    |         ^^^^^^^^^^^^^^^^^^^^
 
-error: demangling-alt(issue_60925::foo::Foo<issue_60925::llv$6d$..Foo$GT$::foo)
+error: demangling-alt(issue_60925::foo::Foo<issue_60925::llv$u6d$..Foo$GT$::foo)
   --> $DIR/issue-60925.rs:21:9
    |
 LL |         #[rustc_symbol_name]

Diff for: src/test/ui/symbol-names/issue-60925.rs

@@ -19,9 +19,9 @@ mod foo {
 
     impl Foo<::llvm::Foo> {
         #[rustc_symbol_name]
-        //[legacy]~^ ERROR symbol-name(_ZN11issue_609253foo36Foo$LT$issue_60925..llv$6d$..Foo$GT$3foo
-        //[legacy]~| ERROR demangling(issue_60925::foo::Foo<issue_60925::llv$6d$..Foo$GT$::foo
-        //[legacy]~| ERROR demangling-alt(issue_60925::foo::Foo<issue_60925::llv$6d$..Foo$GT$::foo)
+        //[legacy]~^ ERROR symbol-name(_ZN11issue_609253foo37Foo$LT$issue_60925..llv$u6d$..Foo$GT$3foo
+        //[legacy]~| ERROR demangling(issue_60925::foo::Foo<issue_60925::llv$u6d$..Foo$GT$::foo
+        //[legacy]~| ERROR demangling-alt(issue_60925::foo::Foo<issue_60925::llv$u6d$..Foo$GT$::foo)
          //[v0]~^^^^ ERROR symbol-name(_RNvMNtCs4fqI2P2rA04_11issue_609253fooINtB2_3FooNtNtB4_4llvm3FooE3foo)
             //[v0]~| ERROR demangling(<issue_60925[317d481089b8c8fe]::foo::Foo<issue_60925[317d481089b8c8fe]::llvm::Foo>>::foo)
             //[v0]~| ERROR demangling-alt(<issue_60925::foo::Foo<issue_60925::llvm::Foo>>::foo)