From: Tom Tromey <tromey@adacore.com>
Date: Tue, 18 Oct 2022 17:32:52 +0000 (-0600)
Subject: Fix regression in pointer-to-member printing
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=86430497337968e6163aef370c6312e7b5ed6504;p=binutils-gdb.git

Fix regression in pointer-to-member printing

PR c++/29243 points out that "info func" on a certain C++ executable
will cause an infinite loop in gdb.

I tracked this down to a bug introduced by commit 6b5a7bc76 ("Handle
member pointers directly in generic_value_print").  Before this
commit, the C++ code to print a member pointer would wind up calling
value_print_scalar_formatted; but afterward it simply calls
generic_value_print and gets into a loop.

This patch restores the previous behavior and adds a regression test.
---

diff --git a/gdb/testsuite/gdb.cp/member-ptr.cc b/gdb/testsuite/gdb.cp/member-ptr.cc
index 22ffcc58d39..a563d2e6af3 100644
--- a/gdb/testsuite/gdb.cp/member-ptr.cc
+++ b/gdb/testsuite/gdb.cp/member-ptr.cc
@@ -142,6 +142,11 @@ int Diamond::vget_base ()
   return this->Left::x + 2000;
 }
 
+struct Container
+{
+  PMI member;
+};
+
 int
 func (int x)
 {
@@ -205,6 +210,9 @@ int main ()
   null_pmi = NULL;
   null_pmf = NULL;
 
+  Container contain;
+  contain.member = &A::j;
+
   pmi = NULL; /* Breakpoint 1 here.  */
 
   (diamond.*diamond_pfunc_ptr) (20);
diff --git a/gdb/testsuite/gdb.cp/member-ptr.exp b/gdb/testsuite/gdb.cp/member-ptr.exp
index 110497b893b..5b91bcb493a 100644
--- a/gdb/testsuite/gdb.cp/member-ptr.exp
+++ b/gdb/testsuite/gdb.cp/member-ptr.exp
@@ -628,3 +628,7 @@ gdb_test "print null_pmi = 0" "$vhn = NULL"
 gdb_test "print null_pmf" "$vhn = NULL"
 gdb_test "print null_pmf = &A::foo" "$vhn = \\(int \\(A::\\*\\)\\(A \\*( const)?, int\\)\\) $hex <A::foo ?\\(int\\)>"
 gdb_test "print null_pmf = 0" "$vhn = NULL"
+
+# Print with a format, bypassing the direct call to the scalar
+# printer.  See PR c++/29243.
+gdb_test "print/x contain" " = {member = $hex}"
diff --git a/gdb/valprint.c b/gdb/valprint.c
index 25db57ea794..48d611ecf8a 100644
--- a/gdb/valprint.c
+++ b/gdb/valprint.c
@@ -879,7 +879,7 @@ generic_value_print_memberptr
       cp_print_class_member (valaddr, type, stream, "&");
     }
   else
-    generic_value_print (val, stream, recurse, options, decorations);
+    value_print_scalar_formatted (val, options, 0, stream);
 }
 
 /* See valprint.h.  */