fix: Remove excessive CF_NOESCAPE and NS_NOESCAPE

[pkryger]

Analysed all occurrences of CF_NOESCAPE and NS_NOESCAPE and removed
where the annotation seemed to be excessive, for example when the
annotated block has been enqueued in a queue to execute in another loop.

Such a block, may have a an optimised placement as
NSConcreteGlobalBlock on stack on a callee side. This happen on
non-Apple clang Apple at least in version 7 (see [1]).

This is slightly different than fully disabling the blocks (see [2],
[3], and [4]), while trying to preserve as much of the NOESCAPES where
it seems to server a purpose.

• src/macappkit.m (mac_within_gui, mac_within_lisp,
  mac_within_gui_and_here, mac_within_gui_allowing_inner_lisp): Remove
  excessive CF_NOESCAPE, for blocks that are passed and executed in
  other threads.
• src/macterm.h (mac_within_gui) : Remove excessive CF_NOESCAPE, for
  blocks that are passed and executed in other threads.
• src/macappkit.h (enumerateChildWindowsUsingBlock): Harmonise
  NS_NOESCAPE placement.
• src/macappkit.m (enumerateChildWindowsUsingBlock): Harmonise
  CF_NOESCAPE placement.

[1] NixOS/nixpkgs#127902 (comment)
[2] #43
[3] #48
[4] #69

[jdtsmith]

Is this just for consistency or does the order of the caret matter?

[pkryger]

That's right, this is for consistency only, the order doesn't matter.

Details

In a context of this gist.

I compiled a small example (just most important bits):

#define MY_NOESCAPE __attribute__ ((noescape))
void queue_block_1(void (^ MY_NOESCAPE block) (void)) {...}
void queue_block_2(void (MY_NOESCAPE ^block) (void)) {...}
void queue_block_3(MY_NOESCAPE void (^block) (void)) {...}
void queue_1(const char* arg)
{
  queue_block_1(^{
      printf("block_1: %s\n", arg);
    });
}

void queue_2(const char* arg)
{
  queue_block_2(^{
      printf("block_2: %s\n", arg);
    });
}

void queue_3(const char* arg)
{
  queue_block_3(^{
      printf("block_3: %s\n", arg);
    });
}

with $(brew --prefix llvm)/bin/clang -g -framework CoreFoundation -o reproducer_123 reproducer.m and then:

(lldb) dis -n queue_1
reproducer_123`queue_1:
[...]
reproducer_123[0x100000828] <+32>: mov    w8, #-0x2f800000 ; =-796917760
[...]
(lldb) dis -n queue_2
reproducer_123`queue_2:
[...]
reproducer_123[0x1000008c4] <+32>: mov    w8, #-0x2f800000 ; =-796917760
(lldb) dis -n queue_3
reproducer_123`queue_3:
[...]
reproducer_123[0x100000960] <+32>: mov    w8, #-0x2f800000 ; =-796917760

[jdtsmith]

Here the idea is that block_here is executed locally, and so does not escape?

[pkryger]

Exactly that.

This is the only usage of block_here

[jdtsmith]

Thanks for your contribution!