Back-port fix for RHBZ 2152431

Fixes RHBZ 2152431, an issue where reading a label symbol's value would cause GDB to crash. This pulls in two upstream commits 38665d717a3 and c3efaf0afd9 both of which should be in GDB 13 when it is released.
2023-01-16 15:03:45 +00:00 · 2023-01-16 15:03:45 +00:00 · 55415aed1f
parent ce6c56f4af
commit 55415aed1f
4 changed files with 190 additions and 0 deletions
--- a/_gdb.spec.Patch.include
+++ b/_gdb.spec.Patch.include
@ -313,3 +313,7 @@ Patch074: gdb-rhbz1553104-s390x-arch12-test.patch

 Patch075: gdb-backport-readline_support.patch

+# Back-port upstream commits 38665d717a and c3efaf0afd to fix
+# bug 2152431.
+Patch076: gdb-rhbz2152431-label-symbol-value.patch
+
--- a/_gdb.spec.patch.include
+++ b/_gdb.spec.patch.include
@ -73,3 +73,4 @@
 %patch073 -p1
 %patch074 -p1
 %patch075 -p1
+%patch076 -p1
--- a/1
+++ b/1
@ -73,3 +73,4 @@ gdb-libexec-add-index.patch
 gdb-rhbz1398387-tab-crash-test.patch
 gdb-rhbz1553104-s390x-arch12-test.patch
 gdb-backport-readline_support.patch
+gdb-rhbz2152431-label-symbol-value.patch
--- a/gdb-rhbz2152431-label-symbol-value.patch
+++ b/gdb-rhbz2152431-label-symbol-value.patch
@ -0,0 +1,184 @@
+From FEDORA_PATCHES Mon Sep 17 00:00:00 2001
+From: Andrew Burgess <aburgess@redhat.com>
+Date: Mon, 16 Jan 2023 14:59:30 +0000
+Subject: gdb-rhbz2152431-label-symbol-value.patch
+
+;; Back-port upstream commits 38665d717a and c3efaf0afd to fix
+;; bug 2152431.
+
+Backport these two upstream commits to fix bug 2152431:
+
+  commit 38665d717a3e65c70e6432243d5eed9728a4888a
+  Date:   Mon Dec 12 14:09:40 2022 +0000
+
+      gdb: use gdb_assert not internal_error
+
+And:
+
+  commit c3efaf0afd9d37004c42cdfd3ce0c1bfa979c45e
+  Date:   Mon Dec 12 14:05:22 2022 +0000
+
+      gdb: fix crash when getting the value of a label symbol
+
+diff --git a/gdb/findvar.c b/gdb/findvar.c
+--- a/gdb/findvar.c
+++ b/gdb/findvar.c
+@@ -152,11 +152,7 @@ extract_long_unsigned_integer (const gdb_byte *addr, int orig_len,
+ CORE_ADDR
+ extract_typed_address (const gdb_byte *buf, struct type *type)
+ {
+-  if (!type->is_pointer_or_reference ())
+-    internal_error (__FILE__, __LINE__,
+-		    _("extract_typed_address: "
+-		    "type is not a pointer or reference"));
+-
+  gdb_assert (type->is_pointer_or_reference ());
+   return gdbarch_pointer_to_address (type->arch (), type, buf);
+ }
+ 
+@@ -205,11 +201,7 @@ template void store_integer (gdb_byte *addr, int len,
+ void
+ store_typed_address (gdb_byte *buf, struct type *type, CORE_ADDR addr)
+ {
+-  if (!type->is_pointer_or_reference ())
+-    internal_error (__FILE__, __LINE__,
+-		    _("store_typed_address: "
+-		    "type is not a pointer or reference"));
+-
+  gdb_assert (type->is_pointer_or_reference ());
+   gdbarch_address_to_pointer (type->arch (), type, buf, addr);
+ }
+ 
+@@ -634,19 +626,32 @@ language_defn::read_var_value (struct symbol *var,
+ 
+     case LOC_LABEL:
+       /* Put the constant back in target format.  */
+-      v = allocate_value (type);
+-      if (overlay_debugging)
+-	{
+-	  struct objfile *var_objfile = symbol_objfile (var);
+-	  addr = symbol_overlayed_address (SYMBOL_VALUE_ADDRESS (var),
+-					   var->obj_section (var_objfile));
+-	  store_typed_address (value_contents_raw (v).data (), type, addr);
+-	}
+-      else
+-	store_typed_address (value_contents_raw (v).data (), type,
+-			      SYMBOL_VALUE_ADDRESS (var));
+-      VALUE_LVAL (v) = not_lval;
+-      return v;
+      {
+	/* Put the constant back in target format.  */
+	if (overlay_debugging)
+	  {
+	    struct objfile *var_objfile = symbol_objfile (var);
+	    addr = symbol_overlayed_address (SYMBOL_VALUE_ADDRESS (var),
+					     var->obj_section (var_objfile));
+	  }
+	else
+	  addr = SYMBOL_VALUE_ADDRESS (var);
+
+	/* First convert the CORE_ADDR to a function pointer type, this
+	   ensures the gdbarch knows what type of pointer we are
+	   manipulating when value_from_pointer is called.  */
+	type = builtin_type (symbol_arch (var))->builtin_func_ptr;
+	v = value_from_pointer (type, addr);
+
+	/* But we want to present the value as 'void *', so cast it to the
+	   required type now, this will not change the values bit
+	   representation.  */
+	struct type *void_ptr_type
+	  = builtin_type (symbol_arch (var))->builtin_data_ptr;
+	v = value_cast_pointers (void_ptr_type, v, 0);
+	VALUE_LVAL (v) = not_lval;
+	return v;
+      }
+ 
+     case LOC_CONST_BYTES:
+       if (is_dynamic_type (type))
+diff --git a/gdb/testsuite/gdb.python/py-label-symbol-value.c b/gdb/testsuite/gdb.python/py-label-symbol-value.c
+new file mode 100644
+--- /dev/null
+++ b/gdb/testsuite/gdb.python/py-label-symbol-value.c
+@@ -0,0 +1,38 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2022 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see  <http://www.gnu.org/licenses/>.  */
+
+volatile int global_var = 1;
+
+int
+get_value ()
+{
+  return global_var;
+}
+
+int
+main (void)
+{
+  int value = get_value ();
+  if (value > 0)
+    goto some_label;
+
+  return 1;
+
+ some_label:
+
+  return 0;
+}
+diff --git a/gdb/testsuite/gdb.python/py-label-symbol-value.exp b/gdb/testsuite/gdb.python/py-label-symbol-value.exp
+new file mode 100644
+--- /dev/null
+++ b/gdb/testsuite/gdb.python/py-label-symbol-value.exp
+@@ -0,0 +1,39 @@
+# Copyright 2022 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Check that GDB handles the user asking for the value of a label
+# symbol (i.e. a symbol for a goto label).
+
+load_lib gdb-python.exp
+standard_testfile
+
+if { [prepare_for_testing "failed to prepare" ${testfile} ${srcfile}] } {
+    return -1
+}
+
+# Skip all tests if Python scripting is not enabled.
+if { [skip_python_tests] } { continue }
+
+if ![runto_main] {
+   return -1
+}
+
+# Use Python to print the value of the 'some_label' symbol.
+gdb_test "python frame = gdb.selected_frame()"
+gdb_test "python frame_pc = frame.pc()"
+gdb_test "python block = gdb.current_progspace().block_for_pc(frame_pc)"
+gdb_test "python symbol,_ = gdb.lookup_symbol('some_label', block, gdb.SYMBOL_LABEL_DOMAIN)"
+gdb_test "python print(str(symbol.value()))" "$hex <main\\+$decimal>"
+gdb_test "python print(str(symbol.value().type))" "void \\*"