[interp] Add missing exception checkpoints (mono#6917)

BrzVlad · web-flow · commit e2419dee784e · 2018-02-15T20:27:32.000+02:00
On interp we can't async abort since we cannot unwind from an ip in the interp, so the interpreter does explicit checks as part of branch instructions.

Note this can lead to increased stack usage when compiling with -O0.
diff --git a/mono/mini/interp/interp.c b/mono/mini/interp/interp.c
@@ -2794,13 +2794,9 @@ interp_exec_method_full (InterpFrame *frame, ThreadContext *context, guint16 *st
 				g_warning ("ret.vt: more values on stack: %d", sp-frame->stack);
 			goto exit_frame;
 		MINT_IN_CASE(MINT_BR_S)
-			/* Checkpoint to be able to handle aborts */
-			EXCEPTION_CHECKPOINT;
 			ip += (short) *(ip + 1);
 			MINT_IN_BREAK;
 		MINT_IN_CASE(MINT_BR)
-			/* Checkpoint to be able to handle aborts */
-			EXCEPTION_CHECKPOINT;
 			ip += (gint32) READ32(ip + 1);
 			MINT_IN_BREAK;
 #define ZEROP_S(datamem, op) \
@@ -3650,6 +3646,11 @@ interp_exec_method_full (InterpFrame *frame, ThreadContext *context, guint16 *st
 
 			THROW_EX ((MonoException *)sp->data.p, ip);
 			MINT_IN_BREAK;
+		MINT_IN_CASE(MINT_CHECKPOINT)
+			/* Do synchronous checking of abort requests */
+			EXCEPTION_CHECKPOINT;
+			++ip;
+			MINT_IN_BREAK;
 		MINT_IN_CASE(MINT_LDFLDA_UNSAFE)
 			o = sp [-1].data.p;
 			sp[-1].data.p = (char *)o + * (guint16 *)(ip + 1);
diff --git a/mono/mini/interp/mintops.def b/mono/mini/interp/mintops.def
@@ -179,6 +179,8 @@ OPDEF(MINT_THROW, "throw", 1, MintOpNoArgs)
 OPDEF(MINT_RETHROW, "rethrow", 2, MintOpUShortInt)
 OPDEF(MINT_ENDFINALLY, "endfinally", 2, MintOpNoArgs)
 
+OPDEF(MINT_CHECKPOINT, "checkpoint", 1, MintOpNoArgs)
+
 OPDEF(MINT_BRFALSE_I4, "brfalse.i4", 3, MintOpBranch)
 OPDEF(MINT_BRFALSE_I8, "brfalse.i8", 3, MintOpBranch)
 OPDEF(MINT_BRFALSE_R8, "brfalse.r8", 3, MintOpBranch)
diff --git a/mono/mini/interp/transform.c b/mono/mini/interp/transform.c
@@ -313,6 +313,9 @@ handle_branch (TransformData *td, int short_op, int long_op, int offset)
 	int target = td->ip + offset - td->il_code;
 	if (target < 0 || target >= td->code_size)
 		g_assert_not_reached ();
+	/* Add exception checkpoint for backward branches */
+	if (offset < 0)
+		ADD_CODE(td, MINT_CHECKPOINT);
 	if (offset > 0 && td->stack_height [target] < 0) {
 		td->stack_height [target] = td->sp - td->stack;
 		if (td->stack_height [target] > 0)
diff --git a/mono/tests/Makefile.am b/mono/tests/Makefile.am
@@ -1021,7 +1021,6 @@ INTERP_DISABLED_TESTS = \
 	$(if $(CI),$(CI_DISABLED_TESTS)) \
 	$(if $(CI_PR),$(CI_PR_DISABLED_TESTS)) \
 	appdomain-unload.exe \
-	async-exc-compilation.exe \
 	async-with-cb-throws.exe \
 	block_guard_restore_aligment_on_exit.exe \
 	bug-335131.2.exe \
