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>

diff --git a/libstdc++-v3/python/Makefile.am b/libstdc++-v3/python/Makefile.am
index 01517a2..0c2b207 100644 (file)
--- 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 c35dbe5..2efe0b9 100644 (file)
--- 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