Clang crashes with the regparam function attribute when targeting AArch64

[llvmbot]

Bugzilla Link	24214
Resolution	FIXED
Resolved on	Jul 28, 2015 09:32
Version	trunk
OS	FreeBSD
Attachments	Example showing the assert
Reporter	LLVM Bugzilla Contributor
CC	@DimitryAndric,@emaste,@kbeyls,@rengolin

Extended Description

The AArch64TargetInfo class sets RegParmMax to 8, however in include/clang/Basic/TargetInfo.h there is an assert that RegParmMax < 7.

The attached file shows the issue when built with:
clang -cc1 -triple aarch64-unknown-freebsd11.0 regparam_test.c

Building this with clang 3.6 from FreeBSD and clang 3.8 I get the following:

Assertion failed: (RegParmMax < 7 && "RegParmMax value is larger than AST can handle"), function getRegParmMax, file /home/andrew/freebsd/repo/llvm/tools/clang/include/clang/Basic/TargetInfo.h, line 824.

[kbeyls]

IIUC, the expected behaviour is to produce an error on the attached file, just like clang does for other non-x86 backends?

$ clang -target armv7 t.c
t.c:1:32: error: 'regparm' is not valid on this platform
void foo(void) attribute ((regparm(3)));
^ ~
1 error generated.

[emaste]

IIUC, the expected behaviour is to produce an error on the attached file,
just like clang does for other non-x86 backends?

That seems correct to me. It looks like the port failures we're encountering are caused by using regparm unconditionally, rather than in some x86 #ifdef - e.g., http://www.ohse.de/uwe/ftpcopy/ has

#if GNUC_MINIMUM(2,7) /* doesn't work reliable before, IIRC */

define attribute_regparm(x) attribute((regparm((x))))

#else

define attribute_regparm(x)

#endif

static void attribute_regparm(2)
outplus(uogetopt_env *e, const char *s)
{ ...

So there are likely bugs for us to file for each of these ports, although the compiler should also behave as you suggest.

[kbeyls]

This is fixed by r243417.