[lld-macho] Demangle symbol name in export error msg when -demangle is specified

[oontvoo]

Summary

PR/55512

[keith]

lld/test/MachO/demangle.s

22

super nit: missing space after :

[oontvoo]

nop update to test arc diff

[oontvoo]

updated diff:

• addressed review comment
• trimmed error msg

[oontvoo]

rebase

[oontvoo]

Thanks!

[oontvoo]

Seemed to fail on windows bot:

$ ":" "RUN: at line 12"
$ "not" "ld64.lld" "-arch" "x86_64" "-platform_version" "macos" "11.0" "11.0" "-syslibroot" "C:/buildbot-root/llvm-clang-x86_64-sie-win/llvm-project/lld/test\MachO\Inputs\MacOSX.sdk" "-fatal_warnings" "-exported_symbol" "__ZTIN3foo3bar4MethE" "-exported_symbol" "__ZTSN3foo3bar4MethE" "C:\buildbot-root\llvm-clang-x86_64-sie-win\build\tools\lld\test\MachO\Output\demangle.s.tmp/export-symbols.o" "-o" "/dev/null"
$ "c:\buildbot-root\llvm-clang-x86_64-sie-win\build\bin\filecheck.exe" "--check-prefix=EXPORT" "C:\buildbot-root\llvm-clang-x86_64-sie-win\llvm-project\lld\test\MachO\demangle.s"
$ ":" "RUN: at line 13"
$ "not" "ld64.lld" "-arch" "x86_64" "-platform_version" "macos" "11.0" "11.0" "-syslibroot" "C:/buildbot-root/llvm-clang-x86_64-sie-win/llvm-project/lld/test\MachO\Inputs\MacOSX.sdk" "-fatal_warnings" "-demangle" "-exported_symbol" "__ZTIN3foo3bar4MethE" "-exported_symbol" "__ZTSN3foo3bar4MethE" "C:\buildbot-root\llvm-clang-x86_64-sie-win\build\tools\lld\test\MachO\Output\demangle.s.tmp/export-symbols.o" "-o" "/dev/null"
$ "c:\buildbot-root\llvm-clang-x86_64-sie-win\build\bin\filecheck.exe" "--check-prefix=DEMANGLE-EXPORT" "C:\buildbot-root\llvm-clang-x86_64-sie-win\llvm-project\lld\test\MachO\demangle.s"
# command stderr:
C:\buildbot-root\llvm-clang-x86_64-sie-win\llvm-project\lld\test\MachO\demangle.s:22:20: error: DEMANGLE-EXPORT: expected string not found in input
# DEMANGLE-EXPORT: cannot export hidden symbol typeinfo for foo::bar::Meth
                   ^
<stdin>:4:78: note: scanning from here
ld64.lld: error: cannot export hidden symbol typeinfo name for foo::bar::Meth
                                                                             ^
<stdin>:5:101: note: possible intended match here
>>> defined in C:\buildbot-root\llvm-clang-x86_64-sie-win\build\tools\lld\test\MachO\Output\demangle.s.tmp/export-symbols.o
                                                                                                    ^

Input file: <stdin>
Check file: C:\buildbot-root\llvm-clang-x86_64-sie-win\llvm-project\lld\test\MachO\demangle.s

-dump-input=help explains the following input dump.

[oontvoo]

Oh I see - the test is bad because it was expecting the error messages to be in a particular order. (it shouldn't because the export symbol list is processed concurrentlly)

[thakis]

Linker behavior, including error output order, should be deterministic. (This allows caching results etc)

So it's not the test that's bad, it's the code.

I'd advise reverting and fixing async.

[oontvoo]

In D125732#3517791, @thakis wrote:

Linker behavior, including error output order, should be deterministic. (This allows caching results etc)

I agree.

So it's not the test that's bad, it's the code.

I'd advise reverting and fixing async.

However the indeterminism isn't introduced by this patch. It's been there already (that is, the code that checks the list of exported symbols runs in parallel)
will look into how to fix the indeterminism there.

All this patch does is to change how the symbol names get printed, not when.

lld/MachO/Driver.cpp

if (!config->exportedSymbols.empty()) {
             if (defined->privateExtern) {
               if (defined->weakDefCanBeHidden) {
                 // weak_def_can_be_hidden symbols behave similarly to
                 // private_extern symbols in most cases, except for when
                 // it is explicitly exported.
                 // The former can be exported but the latter cannot.
                 defined->privateExtern = false;
               } else {
-                warn("cannot export hidden symbol " + symbolName +
+                warn("cannot export hidden symbol " + toString(*defined) +
                      "\n>>> defined in " + toString(defined->getFile()));
               }
             }
           } else {
             defined->privateExtern = true;
           }
         }
       });

lld/test/MachO/demangle.s

 # REQUIRES: x86
 
-# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %s -o %t.o
+# RUN: rm -rf %t; split-file %s %t
 
-# RUN: not %lld %t.o -o /dev/null 2>&1 | FileCheck %s
-# RUN: not %lld -demangle %t.o -o /dev/null 2>&1 | \
-# RUN:     FileCheck --check-prefix=DEMANGLE %s
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %t/undefined-symbol.s -o %t/undefined-symbol.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %t/export-symbols.s -o %t/export-symbols.o
 
-# CHECK: undefined symbol: __Z1fv
-# DEMANGLE: undefined symbol: f()
+# RUN: not %lld %t/undefined-symbol.o -o /dev/null 2>&1 | FileCheck --check-prefix=UNDEF %s
+# RUN: not %lld -demangle %t/undefined-symbol.o -o /dev/null 2>&1 | \
+# RUN:     FileCheck --check-prefix=DEMANGLE-UNDEF %s
 
+# RUN: not %lld -exported_symbol __ZTIN3foo3bar4MethE -exported_symbol __ZTSN3foo3bar4MethE %t/export-symbols.o -o /dev/null 2>&1 | FileCheck --check-prefix=EXPORT %s
+# RUN: not %lld -demangle -exported_symbol __ZTIN3foo3bar4MethE -exported_symbol __ZTSN3foo3bar4MethE %t/export-symbols.o -o /dev/null 2>&1 | FileCheck --check-prefix=DEMANGLE-EXPORT %s
+
+# UNDEF: undefined symbol: __Z1fv
+# DEMANGLE-UNDEF: undefined symbol: f()
+
+# EXPORT: cannot export hidden symbol __ZTSN3foo3bar4MethE
+# EXPORT: cannot export hidden symbol __ZTIN3foo3bar4MethE
+
+# DEMANGLE-EXPORT: cannot export hidden symbol typeinfo name for foo::bar::Meth
+# DEMANGLE-EXPORT: cannot export hidden symbol typeinfo for foo::bar::Meth
+
+#--- undefined-symbol.s
 .globl _main
 _main:
   callq __Z1fv
   ret
+
+
+#--- export-symbols.s
+.globl _main
+_main:
+  ret
+
+.globl __ZTIN3foo3bar4MethE
+.weak_def_can_be_hidden __ZTIN3foo3bar4MethE
+.private_extern __ZTIN3foo3bar4MethE
+__ZTIN3foo3bar4MethE:
+  retq
+
+.globl __ZTSN3foo3bar4MethE
+.weak_def_can_be_hidden __ZTSN3foo3bar4MethE
+.private_extern __ZTSN3foo3bar4MethE
+__ZTSN3foo3bar4MethE:
+  retq