Hi, David
As for the "%P" format string, we directly get it from linux kernel source
code, a cpped snippet like below:
# 6 "/fc/home/yug/kernel/opencc-build/arch/x86/include/asm/current.h" 2
struct task_struct;
extern __attribute__((section(".discard"), unused)) char
__pcpu_scope_current_task; extern __attribute__((section(".data.percpu"
""))) __typeo\
f__(struct task_struct *) per_cpu__current_task;
static inline __attribute__((always_inline)) struct task_struct
*get_current(void)
{
return ({ typeof(per_cpu__current_task) ret__; switch
(sizeof(per_cpu__current_task)) { case 1: asm("mov" "b ""%%""gs"":%P"
"1"",%0" : "=q" (\
ret__) : "p" (&per_cpu__current_task)); break; case 2: asm("mov" "w
""%%""gs"":%P" "1"",%0" : "=r" (ret__) : "p" (&per_cpu__current_task)); br\
eak; case 4: asm("mov" "l ""%%""gs"":%P" "1"",%0" : "=r" (ret__) : "p"
(&per_cpu__current_task)); break; case 8: asm("mov" "q ""%%""gs"":%P" "\
1"",%0" : "=r" (ret__) : "p" (&per_cpu__current_task)); break; default:
__bad_percpu_size(); } ret__; });
}
it is macro expansion result and not ready to read, so I provide the cpped
result.
As for the gcc failed bug-cases,
I think you use gcc O0 to test, for the fail reason, because gcc does not
localize the local char * per_cpu__kernel_stack to a memory location, so
&per_cpu__kernel_stack is reloaded as a register, that cause the assembler
assert. open64 does different for this case, so it does well.
If you have further interest, please check out:
https://svn.open64.net/svnroot/open64/regression_test
runtest open64.exp=bug597,bug597-1,bug597-2,....,bug597-9
Thanks
Regards
Gang
On Wed, Nov 16, 2011 at 7:38 AM, David Coakley <dcoak...@gmail.com> wrote:
> Hi Gang,
>
> Your example is slightly more readable if you remove the extra quotes
> in the format string:
>
> void test(void)
> {
> char *per_cpu__kernel_stack;
> void *ret__;
> asm volatile ("movq %%gs:%P1,%0"
> : "=q" (ret__)
> : "p" (&per_cpu__kernel_stack));
> }
>
> You can see "%P" is part of the name "%P1", and 'P' is not documented
> as a valid modifier. It doesn't compile for me with gcc-4.1.2 or
> gcc-4.5.3:
>
> > gcc -c t.c
> t.c: Assembler messages:
> t.c:5: Error: bad memory operand `%rax'
>
> It does compile if I remove the 'P'. I understand the part of the bug
> related to adding support for the 'p' constraint. Are you sure the
> code related to capital 'P' in the format string is valid for x86?
>
> -David Coakley / AMD Open Source Compiler Engineering
>
>
> On Mon, Nov 14, 2011 at 5:40 PM, Gang Yu <yugang...@gmail.com> wrote:
> > Thank you, Sun
> >
> > As for the inline asm format string such as "%P", I google it but seems
> very
> > few document on it. If people can provide relevant docs or links, it
> will be
> > greatly appreciated, we can further improve it.
> >
> > Regards
> > Gang
> >
> >
> > On Tue, Nov 15, 2011 at 12:18 AM, Sun Chan <sun.c...@gmail.com> wrote:
> >>
> >> I am fine with this (although I suspect the use of strstr on %P may be
> not
> >> covering some error situations)
> >> Sun
> >>
> >> On Mon, Nov 14, 2011 at 8:35 PM, Gang Yu <yugang...@gmail.com> wrote:
> >>>
> >>> Hi,
> >>>
> >>> Could a gatekeeper please help review the fix for bug597, constraint
> >>> <p> not implemented assertion? Thanks very much.
> >>>
> >>> Current status:
> >>>
> >>> open64 does not implement the "p" asm constraint for x86_64 target,
> >>> assertion throws out:
> >>>
> >>> void test(void)
> >>> {
> >>> char *per_cpu__kernel_stack;
> >>> void *ret__;
> >>> asm volatile ("mov" "q ""%%""gs"":%P" "1"",%0"
> >>> : "=q" (ret__)
> >>> : "p" (&per_cpu__kernel_stack));
> >>> }
> >>>
> >>> ### Assertion failure at line 3323 of
> >>>
> >>>
> /export/proj/linux_test/o64guru/base/trunk/objdir/osprey/../../osprey/be/cg/x8664/cgtarget.cxx:
> >>> ### Compiler Error in file asm-4.c during Code_Expansion phase:
> >>> ### ASM constraint <p> not supported
> >>>
> >>> The patch below
> >>>
> >>> --- a/osprey/be/cg/cgemit.cxx
> >>> +++ b/osprey/be/cg/cgemit.cxx
> >>> @@ -3526,13 +3526,17 @@ Modify_Asm_String (char* asm_string, UINT32
> >>> position, bool memory,
> >>> asm_string = Replace_Substring(asm_string, replace, name);
> >>> *name = tmp;
> >>> }
> >>> - if (strstr(asm_string, "%P")) {
> >>> - char replace[5];
> >>> - sprintf(replace, "%%P%d", position);
> >>> - // OSP_323, with "%P", we ignore the first character '$'
> >>> - asm_string = Replace_Substring(asm_string, replace, name+1);
> >>> - }
> >>> }
> >>> + if (strstr(asm_string, "%P")) {
> >>> + char replace[5];
> >>> + sprintf(replace, "%%P%d", position);
> >>> + // OSP_323, with "%P", we ignore the first character '$'
> >>> + if (*name == '$')
> >>> + asm_string = Replace_Substring(asm_string, replace, name+1);
> >>> + else
> >>> + asm_string = Replace_Substring(asm_string, replace, name);
> >>> + }
> >>> +
> >>> // Follow the zero dialect_number implementation as in
> >>> // gcc/final.c:output_asm_insn and handle {, } and | operators
> >>> if (strchr(asm_string, '{')) {
> >>> diff --git a/osprey/be/cg/x8664/cgtarget.cxx
> >>> b/osprey/be/cg/x8664/cgtarget.cxx
> >>> index e006d31..b1c0e58 100644
> >>> --- a/osprey/be/cg/x8664/cgtarget.cxx
> >>> +++ b/osprey/be/cg/x8664/cgtarget.cxx
> >>> @@ -106,6 +106,7 @@
> >>> #include "cg_loop.h"
> >>> #include "config_lno.h" // for LNO_Prefetch_Ahead
> >>> #include "erbe.h"
> >>> +#include "stblock.h" //for Base_Symbol_And_Offset_For_Addressing
> >>> @@ -3649,6 +3650,50 @@ CGTARG_TN_For_Asm_Operand (const char*
> constraint,
> >>> else
> >>> ret_tn = (pref_tn ? pref_tn :
> >>> Build_RCLASS_TN(ISA_REGISTER_CLASS_float));
> >>> }
> >>> + else if (*constraint == 'p')
> >>> + {
> >>> + FmtAssert(load, (" there must be load expression for constraint
> >>> p\n"));
> >>> + if (load && WN_operator(load)==OPR_LDID &&
> >>> WN_class(load)==CLASS_PREG)
> >>> + {
> >>> + // immediate could have been put in preg by wopt
> >>> + load = Preg_Is_Rematerializable(WN_load_offset(load), NULL);
> >>> + }
> >>> + if (WN_operator(load) == OPR_INTCONST)
> >>> + {
> >>> + if (Is_Target_32bit() && (WN_const_val(load) > INT32_MAX ||
> >>> WN_const_val(load) < INT32_MIN)) {
> >>> + char c[200];
> >>> + sprintf(c,"%lld", WN_const_val(load));
> >>> + ErrMsgSrcpos(EC_Ill_Int_Oflow, WN_Get_Linenum(asm_wn),
> >>> + INT32_MIN,c,INT32_MAX);
> >>> + }
> >>> + ret_tn = Gen_Literal_TN(WN_const_val(load),
> >>> + MTYPE_bit_size(WN_rtype(load))/8);
> >>> + }
> >>> + else if ( WN_operator(load) == OPR_LDA &&
> ST_sym_class(WN_st(load))
> >>> == CLASS_CONST)
> >>> + {
> >>> + ST * base;
> >>> + INT64 ofst;
> >>> + // Allocate the string to the rodata section
> >>> + Allocate_Object (WN_st(load));
> >>> + Base_Symbol_And_Offset (WN_st(load), &base, &ofst);
> >>> + ret_tn = Gen_Symbol_TN(base, ofst, 0);
> >>> + }
> >>> + else if ( WN_operator(load) == OPR_LDA &&
> ST_sym_class(WN_st(load))
> >>> == CLASS_VAR)
> >>> + {
> >>> + ST * base;
> >>> + INT64 ofst;
> >>> + Base_Symbol_And_Offset_For_Addressing (WN_st(load),
> >>> WN_lda_offset(load), &base, &ofst);
> >>> + if (ofst == 0) { //no offset, using a symbol TN
> >>> + ret_tn = Gen_Symbol_TN(base, ofst, 0);
> >>> + } else { //has a offset, using a new TN to express the address
> >>> + ret_tn = (pref_tn ? pref_tn :
> >>> Build_TN_Of_Mtype(WN_rtype(load)));
> >>> + }
> >>> + }
> >>> + else //other cases
> >>> + {
> >>> + ret_tn = (pref_tn ? pref_tn :
> Build_TN_Of_Mtype(WN_rtype(load)));
> >>> + }
> >>> + }
> >>> else
> >>> {
> >>> FmtAssert(FALSE, ("ASM constraint <%s> not supported",
> constraint));
> >>>
> >>> Tests and validation :
> >>>
> >>> This patch has passed regression test bug597,bug597-1,...,bug597-9 and
> >>> there are no such assertions thrown out on the whole kernel(2.6.32-9)
> >>> build.
> >>>
> >>>
> >>> Regards
> >>> Gang
> >>>
> >>>
> >>>
> ------------------------------------------------------------------------------
> >>> RSA(R) Conference 2012
> >>> Save $700 by Nov 18
> >>> Register now
> >>> http://p.sf.net/sfu/rsa-sfdev2dev1
> >>> _______________________________________________
> >>> Open64-devel mailing list
> >>> Open64-devel@lists.sourceforge.net
> >>> https://lists.sourceforge.net/lists/listinfo/open64-devel
> >>>
> >>
> >
> >
> >
> ------------------------------------------------------------------------------
> > RSA(R) Conference 2012
> > Save $700 by Nov 18
> > Register now
> > http://p.sf.net/sfu/rsa-sfdev2dev1
> > _______________________________________________
> > Open64-devel mailing list
> > Open64-devel@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/open64-devel
> >
> >
>
------------------------------------------------------------------------------
RSA(R) Conference 2012
Save $700 by Nov 18
Register now
http://p.sf.net/sfu/rsa-sfdev2dev1
_______________________________________________
Open64-devel mailing list
Open64-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/open64-devel
