[gcc r11-8381] libstdc++: Install libstdc++*-gdb.py more robustly [PR 99453]

[Jonathan Wakely <redi@gcc.gnu.org>]

https://gcc.gnu.org/g:dbb87d6a9c37c8eca80d77782717a8144515c16d

commit r11-8381-gdbb87d6a9c37c8eca80d77782717a8144515c16d
Author: Philippe Blain <levraiphilippeblain@gmail.com>
Date:   Fri Mar 12 19:26:46 2021 -0500

    libstdc++: Install libstdc++*-gdb.py more robustly [PR 99453]
    
    In order for GDB to auto-load the pretty printers, they must be installed
    as "libstdc++.$ext-gdb.py", where 'libstdc++.$ext' is the name of the
    object file that is loaded by GDB [1], i.e. the libstdc++ shared library.
    
    The approach taken in libstdc++-v3/python/Makefile.am is to loop over
    files matching 'libstdc++*' in $(DESTDIR)$(toolexeclibdir) and choose
    the last file matching that glob that is not a symlink, the Libtool
    '*.la' file or a Python file.
    
    That works fine for ELF targets where the matching names are:
    
      libstdc++.a
      libstdc++.so
      libstdc++.so.6
      libstdc++.so.6.0.29
    
    But not for macOS with:
    
      libstdc++.6.dylib
      libstdc++.a
    
    Or MinGW with:
    
      libstdc++-6.dll
      libstdc++.dll.a
    
    Try to make a better job at installing the pretty printers with the
    correct name by copying the approach taken by isl [2], that is, using
    a sed invocation on the Libtool-generated 'libstdc++.la' to read the
    correct name for the current platform.
    
    [1] https://sourceware.org/gdb/onlinedocs/gdb/objfile_002dgdbdotext-file.html
    [2] https://repo.or.cz/isl.git/blob/HEAD:/Makefile.am#l611
    
    libstdc++-v3/ChangeLog:
    
            PR libstdc++/99453
            * python/Makefile.am: Install libstdc++*-gdb.py more robustly.
            * python/Makefile.in: Regenerate.
    
    Co-authored-by: Jonathan Wakely <jwakely@redhat.com>
    (cherry picked from commit c2fc1702cb3a3d5cc9c40de47f63b4c8f3f1d09c)

Diff:
---
 libstdc++-v3/python/Makefile.am | 20 ++++----------------
 libstdc++-v3/python/Makefile.in | 14 ++------------
 2 files changed, 6 insertions(+), 28 deletions(-)

diff --git a/libstdc++-v3/python/Makefile.am b/libstdc++-v3/python/Makefile.am
index 01517a2a522..0c2b207b86e 100644
--- a/libstdc++-v3/python/Makefile.am
+++ b/libstdc++-v3/python/Makefile.am
@@ -44,21 +44,9 @@ gdb.py: hook.in Makefile
 install-data-local: gdb.py
 	@$(mkdir_p) $(DESTDIR)$(toolexeclibdir)
 ## We want to install gdb.py as SOMETHING-gdb.py.  SOMETHING is the
-## full name of the final library.  We want to ignore symlinks, the
-## .la file, and any previous -gdb.py file.  This is inherently
-## fragile, but there does not seem to be a better option, because
-## libtool hides the real names from us.
-	@here=`pwd`; cd $(DESTDIR)$(toolexeclibdir); \
-	  for file in libstdc++.*; do \
-	    case $$file in \
-	      *-gdb.py) ;; \
-	      *.la) ;; \
-	      *) if test -h $$file; then \
-	           continue; \
-	         fi; \
-	         libname=$$file;; \
-	    esac; \
-	  done; \
-	cd $$here; \
+## full name of the final library.  We use the libtool .la file to get
+## the correct name.
+	@libname=`sed -ne "/^library_names=/{s/.*='//;s/'$$//;s/ .*//;p;}" \
+	          $(DESTDIR)$(toolexeclibdir)/libstdc++.la`; \
 	echo " $(INSTALL_DATA) gdb.py $(DESTDIR)$(toolexeclibdir)/$$libname-gdb.py"; \
 	$(INSTALL_DATA) gdb.py $(DESTDIR)$(toolexeclibdir)/$$libname-gdb.py
diff --git a/libstdc++-v3/python/Makefile.in b/libstdc++-v3/python/Makefile.in
index c35dbe55961..2efe0b96a19 100644
--- a/libstdc++-v3/python/Makefile.in
+++ b/libstdc++-v3/python/Makefile.in
@@ -607,18 +607,8 @@ gdb.py: hook.in Makefile
 
 install-data-local: gdb.py
 	@$(mkdir_p) $(DESTDIR)$(toolexeclibdir)
-	@here=`pwd`; cd $(DESTDIR)$(toolexeclibdir); \
-	  for file in libstdc++.*; do \
-	    case $$file in \
-	      *-gdb.py) ;; \
-	      *.la) ;; \
-	      *) if test -h $$file; then \
-	           continue; \
-	         fi; \
-	         libname=$$file;; \
-	    esac; \
-	  done; \
-	cd $$here; \
+	@libname=`sed -ne "/^library_names=/{s/.*='//;s/'$$//;s/ .*//;p;}" \
+	          $(DESTDIR)$(toolexeclibdir)/libstdc++.la`; \
 	echo " $(INSTALL_DATA) gdb.py $(DESTDIR)$(toolexeclibdir)/$$libname-gdb.py"; \
 	$(INSTALL_DATA) gdb.py $(DESTDIR)$(toolexeclibdir)/$$libname-gdb.py