From: Tom Tromey <tom@tromey.com>
Date: Sat, 23 Jan 2021 19:20:11 +0000 (-0700)
Subject: Avoid crash when "compile" expression uses cooked register
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=b10bae18753862874628f902796eb1cd3925f95d;p=binutils-gdb.git

Avoid crash when "compile" expression uses cooked register

If the "compile" command is used with an expression that happens to
require a cooked register, then GDB can crash.  This patch does not
fix the bug, but at least turns the crash into an error instead.

2021-01-23  Tom Tromey  <tom@tromey.com>

	PR compile/25575
	* compile/compile-loc2c.c (note_register): New function.
	(pushf_register_address, pushf_register): Use it.
---

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 8fa20fae30f..9f9681fef84 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2021-01-23  Tom Tromey  <tom@tromey.com>
+
+	PR compile/25575
+	* compile/compile-loc2c.c (note_register): New function.
+	(pushf_register_address, pushf_register): Use it.
+
 2021-01-23  Tom Tromey  <tom@tromey.com>
 
 	* symtab.h (struct symbol_computed_ops) <generate_c_location>:
diff --git a/gdb/compile/compile-loc2c.c b/gdb/compile/compile-loc2c.c
index ee9595c78ed..ef819799eb4 100644
--- a/gdb/compile/compile-loc2c.c
+++ b/gdb/compile/compile-loc2c.c
@@ -505,6 +505,20 @@ print_label (string_file *stream, unsigned int scope, int target)
   stream->printf ("__label_%u_%s", scope, pulongest (target));
 }
 
+/* Note that a register was used.  */
+
+static void
+note_register (int regnum, std::vector<bool> &registers_used)
+{
+  gdb_assert (regnum >= 0);
+  /* If the expression uses a cooked register, then we currently can't
+     compile it.  We would need a gdbarch method to handle this
+     situation.  */
+  if (regnum >= registers_used.size ())
+    error (_("Expression uses \"cooked\" register and cannot be compiled."));
+  registers_used[regnum] = true;
+}
+
 /* Emit code that pushes a register's address on the stack.
    REGISTERS_USED is an out parameter which is updated to note which
    register was needed by this expression.  */
@@ -516,7 +530,7 @@ pushf_register_address (int indent, string_file *stream,
 {
   std::string regname = compile_register_name_mangled (gdbarch, regnum);
 
-  registers_used[regnum] = true;
+  note_register (regnum, registers_used);
   pushf (indent, stream,
 	 "(" GCC_UINTPTR ") &" COMPILE_I_SIMPLE_REGISTER_ARG_NAME "->%s",
 	 regname.c_str ());
@@ -534,7 +548,7 @@ pushf_register (int indent, string_file *stream,
 {
   std::string regname = compile_register_name_mangled (gdbarch, regnum);
 
-  registers_used[regnum] = true;
+  note_register (regnum, registers_used);
   if (offset == 0)
     pushf (indent, stream, COMPILE_I_SIMPLE_REGISTER_ARG_NAME "->%s",
 	   regname.c_str ());