[binutils-gdb] [gdb/testsuite] Fix gdb.cp/break-f-std-string.cc with older gcc

[Tom de Vries <vries@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=c8a9e88bf6ff32d90d082d07d3c5d12b938f8335

commit c8a9e88bf6ff32d90d082d07d3c5d12b938f8335
Author: Tom de Vries <tdevries@suse.de>
Date:   Thu May 12 14:52:41 2022 +0200

    [gdb/testsuite] Fix gdb.cp/break-f-std-string.cc with older gcc
    
    When running test-case gdb.cp/break-f-std-string.exp on openSUSE Leap 15.3
    with system gcc 7.5.0, I run into:
    ...
    (gdb) whatis /r std::string^M
    No symbol "string" in namespace "std".^M
    (gdb) FAIL: gdb.cp/break-f-std-string.exp: _GLIBCXX_USE_CXX11_ABI=1: \
      whatis /r std::string
    ...
    The same for gcc 8.2.1, but it passes with gcc 9.3.1.
    
    At source level (as we can observe in the .ii file with -save-temps) we have
    indeed:
    ...
    namespace std {
      namespace __cxx11 {
        typedef basic_string<char> string;
      }
    }
    ...
    while with gcc 9.3.1, we have instead:
    ...
    namespace std {
      namespace __cxx11 {
        ...
      }
      typedef basic_string<char> string;
    }
    ...
    due to gcc commit 33b43b0d8cd ("Define std::string and related typedefs
    outside __cxx11 namespace").
    
    Fix this by adding the missing typedef for gcc version 5 (the first version to
    have the dual abi) to 8 (the last version missing aforementioned gcc commit).
    
    Tested on x86_64-linux, with:
    - system gcc 7.5.0
    - gcc 4.8.5, 8.2.1, 9.3.1, 10.3.0, 11.2.1
    - clang 8.0.1, 12.0.1

Diff:
---
 gdb/testsuite/gdb.cp/break-f-std-string.cc | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/gdb/testsuite/gdb.cp/break-f-std-string.cc b/gdb/testsuite/gdb.cp/break-f-std-string.cc
index 454ab4c42ea..0c361234d82 100644
--- a/gdb/testsuite/gdb.cp/break-f-std-string.cc
+++ b/gdb/testsuite/gdb.cp/break-f-std-string.cc
@@ -17,6 +17,19 @@
 
 #include <string>
 
+#if _GLIBCXX_USE_CXX11_ABI == 1
+#if defined (__GNUC__) && (__GNUC__ >= 5) && (__GNUC__ <= 8)
+
+/* Work around missing std::string typedef before gcc commit
+   "Define std::string and related typedefs outside __cxx11 namespace".  */
+
+namespace std {
+typedef __cxx11::string string;
+}
+
+#endif
+#endif
+
 void
 f (std::string s)
 {