Wed Jan 13 15:54:53 CET 2010 Paolo Molaro <lupus@ximian.com>

	* jit.h, method-to-ir.c: added ability to set the policy for
	inserting breakpoints from the break IL instruction or the
	Debugger.Break () API call.


svn path=/branches/mono-2-6/mono/; revision=149473

mono/mini/ChangeLog

@@ -1,3 +1,10 @@
+
+Wed Jan 13 15:54:53 CET 2010 Paolo Molaro <lupus@ximian.com>
+
+	* jit.h, method-to-ir.c: added ability to set the policy for
+	inserting breakpoints from the break IL instruction or the
+	Debugger.Break () API call.
+
 2010-01-11  Zoltan Varga  <vargaz@gmail.com>
 
 	* debugger-agent.c (mono_debugger_agent_parse_options): Allow onthrow without

mono/mini/jit.h

@@ -33,6 +33,25 @@ mono_set_signal_chaining   (gboolean chain_signals);
 void
 mono_jit_set_aot_only      (gboolean aot_only);
 
+/* Allow embedders to decide wherther to actually obey breakpoint instructions
+ * in specific methods (works for both break IL instructions and Debugger.Break ()
+ * method calls).
+ */
+typedef enum {
+	/* the default is to always obey the breakpoint */
+	MONO_BREAK_POLICY_ALWAYS,
+	/* a nop is inserted instead of a breakpoint */
+	MONO_BREAK_POLICY_NEVER,
+	/* the breakpoint is executed only if the program has ben started under
+	 * the debugger (that is if a debugger was attached at the time the method
+	 * was compiled).
+	 */
+	MONO_BREAK_POLICY_ON_DBG
+} MonoBreakPolicy;
+
+typedef MonoBreakPolicy (*MonoBreakPolicyFunc) (MonoMethod *method);
+void mono_set_break_policy (MonoBreakPolicyFunc policy_callback);
+
 void
 mono_jit_parse_options     (int argc, char * argv[]);
 

mono/mini/method-to-ir.c

@@ -57,6 +57,7 @@
 #include "ir-emit.h"
 
 #include "jit-icalls.h"
+#include "jit.h"
 #include "debugger-agent.h"
 
 #define BRANCH_COST 100
@@ -3772,6 +3773,53 @@ mini_emit_ldelema_ins (MonoCompile *cfg, MonoMethod *cmethod, MonoInst **sp, uns
 	return addr;
 }
 
+static MonoBreakPolicy
+always_insert_breakpoint (MonoMethod *method)
+{
+	return MONO_BREAK_POLICY_ALWAYS;
+}
+
+static MonoBreakPolicyFunc break_policy_func = always_insert_breakpoint;
+
+/**
+ * mono_set_break_policy:
+ * policy_callback: the new callback function
+ *
+ * Allow embedders to decide wherther to actually obey breakpoint instructions
+ * (both break IL instructions and Debugger.Break () method calls), for example
+ * to not allow an app to be aborted by a perfectly valid IL opcode when executing
+ * untrusted or semi-trusted code.
+ *
+ * @policy_callback will be called every time a break point instruction needs to
+ * be inserted with the method argument being the method that calls Debugger.Break()
+ * or has the IL break instruction. The callback should return #MONO_BREAK_POLICY_NEVER
+ * if it wants the breakpoint to not be effective in the given method.
+ * #MONO_BREAK_POLICY_ALWAYS is the default.
+ */
+void
+mono_set_break_policy (MonoBreakPolicyFunc policy_callback)
+{
+	if (policy_callback)
+		break_policy_func = policy_callback;
+	else
+		break_policy_func = always_insert_breakpoint;
+}
+
+static gboolean
+should_insert_brekpoint (MonoMethod *method) {
+	switch (break_policy_func (method)) {
+	case MONO_BREAK_POLICY_ALWAYS:
+		return TRUE;
+	case MONO_BREAK_POLICY_NEVER:
+		return FALSE;
+	case MONO_BREAK_POLICY_ON_DBG:
+		return mono_debug_using_mono_debugger ();
+	default:
+		g_warning ("Incorrect value returned from break policy callback");
+		return FALSE;
+	}
+}
+
 static MonoInst*
 mini_emit_inst_for_method (MonoCompile *cfg, MonoMethod *cmethod, MonoMethodSignature *fsig, MonoInst **args)
 {
@@ -4130,7 +4178,10 @@ mini_emit_inst_for_method (MonoCompile *cfg, MonoMethod *cmethod, MonoMethodSign
 	} else if (cmethod->klass->image == mono_defaults.corlib) {
 		if (cmethod->name [0] == 'B' && strcmp (cmethod->name, "Break") == 0
 				&& strcmp (cmethod->klass->name, "Debugger") == 0) {
-			MONO_INST_NEW (cfg, ins, OP_BREAK);
+			if (should_insert_brekpoint (cfg->method))
+				MONO_INST_NEW (cfg, ins, OP_BREAK);
+			else
+				MONO_INST_NEW (cfg, ins, OP_NOP);
 			MONO_ADD_INS (cfg->cbb, ins);
 			return ins;
 		}
@@ -5842,7 +5893,10 @@ mono_method_to_ir (MonoCompile *cfg, MonoMethod *method, MonoBasicBlock *start_b
 			MONO_ADD_INS (bblock, ins);
 			break;
 		case CEE_BREAK:
-			MONO_INST_NEW (cfg, ins, OP_BREAK);
+			if (should_insert_brekpoint (cfg->method))
+				MONO_INST_NEW (cfg, ins, OP_BREAK);
+			else
+				MONO_INST_NEW (cfg, ins, OP_NOP);
 			ip++;
 			MONO_ADD_INS (bblock, ins);
 			break;