pgsql: Allow building with MSVC and Strawberry perl

On 2022-11-25 Fr 15:38, Andrew Dunstan wrote:

Allow building with MSVC and Strawberry perl

Strawberry uses __builtin_expect which Visual C doesn't have. For this
case define it as a noop. Solution taken from vim sources.

Argh! drongo doesn't seem to like this. I thought I'd tested it.

A little further googling suggests that instead of

#define __builtin_expect(expr, val) (expr)

we should probably have something like

#define __builtin_expect(expr, val) ((expr) == (val))

I'll try that.

cheers

andrew

--
Andrew Dunstan
EDB: https://www.enterprisedb.com

Hi,

On 2022-11-25 17:11:51 -0500, Andrew Dunstan wrote:

On 2022-11-25 Fr 15:38, Andrew Dunstan wrote:

Allow building with MSVC and Strawberry perl

Strawberry uses __builtin_expect which Visual C doesn't have. For this
case define it as a noop. Solution taken from vim sources.

FWIW, to get a newer strawberry perl to work with msvc we need more than
this. At the very least -DNO_THREAD_SAFE_LOCALE, see

/messages/by-id/20220130221659.tlyr2lbw3wk22owg@alap3.anarazel.de

Argh! drongo doesn't seem to like this. I thought I'd tested it.

A little further googling suggests that instead of

#define __builtin_expect(expr, val) (expr)

we should probably have something like

#define __builtin_expect(expr, val) ((expr) == (val))

That doesn't seem right - val isn't something to compare to, it's the expected
return value. This afaict would compute bogus value in a number of scenarios.

Note that perl's own definition is:

#ifdef HAS_BUILTIN_EXPECT
# define EXPECT(expr,val) __builtin_expect(expr,val)
#else
# define EXPECT(expr,val) (expr)
#endif

So we really should be able to get away with
#define __builtin_expect(expr, val) (expr)

I don't see why drongo's problems would go away with
#define __builtin_expect(expr, val) ((expr) == (val))
anyway?

FWIW a meson build with msvc 2019 and strawberry perl 5.32 builds fine with
#define __builtin_expect(expr, val) (expr)

Greetings,

Andres Freund

Hi,

On 2022-11-25 15:33:31 -0800, Andres Freund wrote:

FWIW a meson build with msvc 2019 and strawberry perl 5.32 builds fine with
#define __builtin_expect(expr, val) (expr)

And it does so with src/tools/msvc as well. I think we might need a
preprocessed plperl.c from drongo to analyze this further.

There might be some unrelated under-specified build issues, I get weird errors
if I start by building plperl.vcxproj, without first having built
postgres.vcxproj. But ...

Greetings,

Andres Freund

On 2022-11-25 Fr 18:48, Andres Freund wrote:

Hi,

On 2022-11-25 15:33:31 -0800, Andres Freund wrote:

FWIW a meson build with msvc 2019 and strawberry perl 5.32 builds fine with
#define __builtin_expect(expr, val) (expr)

And it does so with src/tools/msvc as well. I think we might need a
preprocessed plperl.c from drongo to analyze this further.

There might be some unrelated under-specified build issues, I get weird errors
if I start by building plperl.vcxproj, without first having built
postgres.vcxproj. But ...

Yeah, drongo builds fine too. It's the handshake thing that's the
current issue. I'll see if forcing -DNO_THREAD_SAFE_LOCALE works.

Thanks

cheers

andrew

--
Andrew Dunstan
EDB: https://www.enterprisedb.com

Hi,

On 2022-11-25 18:56:02 -0500, Andrew Dunstan wrote:

On 2022-11-25 Fr 18:48, Andres Freund wrote:

On 2022-11-25 15:33:31 -0800, Andres Freund wrote:

FWIW a meson build with msvc 2019 and strawberry perl 5.32 builds fine with
#define __builtin_expect(expr, val) (expr)

And it does so with src/tools/msvc as well. I think we might need a
preprocessed plperl.c from drongo to analyze this further.

There might be some unrelated under-specified build issues, I get weird errors
if I start by building plperl.vcxproj, without first having built
postgres.vcxproj. But ...

Yeah, drongo builds fine too.

Oh - I just looked at HEAD, where it fails in the 'make' stage on the BF. But
I now see the PLCheck-C failures in the older branches.

It's the handshake thing that's the current issue. I'll see if forcing
-DNO_THREAD_SAFE_LOCALE works.

With it tests do pass for me with meson + msvc + perl 5.32.

Greetings,

Andres Freund