[PATCH] Fix ARM simulator build on Windows

[PATCH] Fix ARM simulator build on Windows

[Tom Tromey via Gdb-patches]

For a Windows-hosted build with arm-elf as the target, the sim build
fails like:

[...]sim-io.c:214:29: error: 'struct host_callback_struct' has no member named 'open'

The recent header reorganization seems to have caused this, because
now 'open' is redefined by the gnulib fcntl.h.

The fix is simple: remove the undef of 'open' from sim-io.c.
---
 sim/common/sim-io.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/sim/common/sim-io.c b/sim/common/sim-io.c
index 8c40f7a0e73..8cc078c3cd2 100644
--- a/sim/common/sim-io.c
+++ b/sim/common/sim-io.c
@@ -37,8 +37,6 @@
 #include "sim-io.h"
 #include "sim/callback.h"
 
-#undef open
-
 /* Define the rate at which the simulator should poll the host
    for a quit. */
 #ifndef POLL_QUIT_INTERVAL
-- 
2.31.1

Re: [PATCH] Fix ARM simulator build on Windows

[Mike Frysinger via Gdb-patches]

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On 09 Dec 2021 07:02, Tom Tromey wrote:
> For a Windows-hosted build with arm-elf as the target, the sim build
> fails like:

what is your --host ?  guessing it's a mingw toolchain.

> [...]sim-io.c:214:29: error: 'struct host_callback_struct' has no member named 'open'
> 
> The recent header reorganization seems to have caused this, because
> now 'open' is redefined by the gnulib fcntl.h.

yeah, i think that's why it started breaking.

> The fix is simple: remove the undef of 'open' from sim-io.c.

mmm, not that simple.  the error you're seeing is because the open macro
rewrote the host_callback_struct structure.  and then we tried to use it,
but they no longer matched.

include/sim/callback.h:
struct host_callback_struct {
  int (*open) (host_callback *, const char*, int mode);

common/sim-io.c:
int sim_io_open (SIM_DESC sd, const char *name, int flags)
{ 
  return STATE_CALLBACK (sd)->open (STATE_CALLBACK (sd), name, flags);
}

i'm not keen on relying on open being defined to a simple symbol name and thus
it will continue to compile.  if it's defined to something more complicated, i
imagine it will still fail to compile.
#define open(args...) _foo_open(1234, ## args)

so i think it's better to move the undef between the system includes and the
local sim includes so it's undone for the header & source.  this file doesn't
use actual open() call, so should be fine.
-mike

--- a/sim/common/sim-io.c
+++ b/sim/common/sim-io.c
@@ -33,12 +33,12 @@
 #include <unistd.h>
 #endif
 
+#undef open
+
 #include "sim-main.h"
 #include "sim-io.h"
 #include "sim/callback.h"
 
-#undef open
-
 /* Define the rate at which the simulator should poll the host
    for a quit. */
 #ifndef POLL_QUIT_INTERVAL

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Re: [PATCH] Fix ARM simulator build on Windows

[Tom Tromey via Gdb-patches]

>> For a Windows-hosted build with arm-elf as the target, the sim build
>> fails like:

Mike> what is your --host ?  guessing it's a mingw toolchain.

Yeah: --host=i686-w64-mingw32

Mike> i'm not keen on relying on open being defined to a simple symbol name and thus
Mike> it will continue to compile.  if it's defined to something more complicated, i
Mike> imagine it will still fail to compile.
Mike> #define open(args...) _foo_open(1234, ## args)

I'm not sure that's an allowable redefinition, but as long as the fix
works, it's fine by me.  Thank you.

Tom