diff options
Diffstat (limited to 'gcc-4.8.1/libgo/runtime/go-deferred-recover.c')
-rw-r--r-- | gcc-4.8.1/libgo/runtime/go-deferred-recover.c | 94 |
1 files changed, 0 insertions, 94 deletions
diff --git a/gcc-4.8.1/libgo/runtime/go-deferred-recover.c b/gcc-4.8.1/libgo/runtime/go-deferred-recover.c deleted file mode 100644 index 78ef287cf..000000000 --- a/gcc-4.8.1/libgo/runtime/go-deferred-recover.c +++ /dev/null @@ -1,94 +0,0 @@ -/* go-deferred-recover.c -- support for a deferred recover function. - - Copyright 2010 The Go Authors. All rights reserved. - Use of this source code is governed by a BSD-style - license that can be found in the LICENSE file. */ - -#include <stddef.h> - -#include "runtime.h" -#include "go-panic.h" -#include "go-defer.h" - -/* This is called when a call to recover is deferred. That is, - something like - defer recover() - - We need to handle this specially. In 6g/8g, the recover function - looks up the stack frame. In particular, that means that a - deferred recover will not recover a panic thrown in the same - function that defers the recover. It will only recover a panic - thrown in a function that defers the deferred call to recover. - - In other words: - - func f1() { - defer recover() // does not stop panic - panic(0) - } - - func f2() { - defer func() { - defer recover() // stops panic(0) - }() - panic(0) - } - - func f3() { - defer func() { - defer recover() // does not stop panic - panic(0) - }() - panic(1) - } - - func f4() { - defer func() { - defer func() { - defer recover() // stops panic(0) - }() - panic(0) - }() - panic(1) - } - - The interesting case here is f3. As can be seen from f2, the - deferred recover could pick up panic(1). However, this does not - happen because it is blocked by the panic(0). - - When a function calls recover, then when we invoke it we pass a - hidden parameter indicating whether it should recover something. - This parameter is set based on whether the function is being - invoked directly from defer. The parameter winds up determining - whether __go_recover or __go_deferred_recover is called at all. - - In the case of a deferred recover, the hidden parameter which - controls the call is actually the one set up for the function which - runs the defer recover() statement. That is the right thing in all - the cases above except for f3. In f3 the function is permitted to - call recover, but the deferred recover call is not. We address - that here by checking for that specific case before calling - recover. If this function was deferred when there is already a - panic on the panic stack, then we can only recover that panic, not - any other. - - Note that we can get away with using a special function here - because you are not permitted to take the address of a predeclared - function like recover. */ - -struct __go_empty_interface -__go_deferred_recover () -{ - G *g; - - g = runtime_g (); - if (g->defer == NULL || g->defer->__panic != g->panic) - { - struct __go_empty_interface ret; - - ret.__type_descriptor = NULL; - ret.__object = NULL; - return ret; - } - return __go_recover (); -} |