On x86_64, the aggregate shown in the test case is partitioned into
two eightbyte pieces. Both of them are classified to INTEGER class and
returned by two 64-bit registers (RAX and RDX).
If the size of the aggregate is larger than 12, both of the two parts
should be MTYPE_I8 and use I8 for LDID/STID. Otherwise, the first part
is MTYE_I8 and the second part should be MTYPE_I4.
2012/7/31 Sun Chan <sun.c...@gmail.com>:
> I think this problem is target dependent. For x86, is 12 bytes wrong?
> I remember it is correct for SGI (which does not matter anymore), but
> the point really is, this is ABI dependent
> Sun
>
> On Tue, Jul 31, 2012 at 4:15 PM, Jian-Xin Lai <laij...@gmail.com> wrote:
>> Hi,
>>
>> Could someone review the patch for open64 bug #969, #970? Thank you very
>> much.
>>
>> 1. test case
>> #969 and #970 can be simplified to the following case:
>> struct I3 {
>> int a, b, c;
>> };
>> extern struct I3 foo();
>> void bar() {
>> struct I3 a;
>> a = foo();
>> }
>>
>> The struct I1 can also be replaced by:
>> struct F3 {
>> float a, b, c;
>> };
>>
>> 2. IR dump
>> Open64 will allocate a temporary on stack for the return value. The IR
>> after MSTID lowering looks like:
>>
>> MCALL 126 <1,51,foo> # flags 0x7e {line: 1/7}
>> I8I8LDID 1 <1,5,.preg_I8> T<5,.predef_I8,8> # $r1
>> I8STID 0 <2,2,_temp_.Mreturn.foo0> T<5,.predef_I8,8> {line: 0/0}
>> I8I8LDID 7 <1,5,.preg_I8> T<5,.predef_I8,8> # $r7
>> I8STID 8 <2,2,_temp_.Mreturn.foo0> T<5,.predef_I8,8> {line: 0/0}
>>
>> [2]: _temp_.Mreturn.foo0 <2,2> Variable of type I1 (#53, KIND_STRUCT)
>> Address: 0(_temp_.Mreturn.foo0<2,2>) Alignment: 8 bytes
>> location: file (null), line 0
>> Flags: 0x00400000 temp, XLOCAL
>> Sclass: AUTO
>>
>> [53]: I3 : (f: 0x1000 content_seen) size 12 M: STRUCT
>> 0 a .predef_I4 (#4) align 4
>> fl:0x0000
>> 4 b .predef_I4 (#4) align 4
>> fl:0x0000
>> 8 c .predef_I4 (#4) align 4
>> fl:0x0001 last_field
>>
>> The size of _temp_.Mreturn.foo0 is only 12 byte. The I8STID will
>> overwrite some other variables on stack. For float struct F3, two
>> F8STID will be generated.
>>
>> 3. Patch
>> Index: osprey/be/com/wn_lower.cxx
>> ===================================================================
>> --- osprey/be/com/wn_lower.cxx (revision 3998)
>> +++ osprey/be/com/wn_lower.cxx (working copy)
>> @@ -7299,6 +7299,7 @@
>> }
>> else { // return via 1 or more return registers
>> TYPE_ID mtype, desc;
>> + WN_OFFSET st_ofst = WN_store_offset(tree);
>> for (INT32 i = 0; i < RETURN_INFO_count(return_info); i++) {
>> if (i != 0)
>> WN_INSERT_BlockLast (block, wn); // insert the last STID created
>> @@ -7334,8 +7335,9 @@
>> }
>> #endif
>> wn = WN_CreateStid(OPR_STID, MTYPE_V, desc,
>> - WN_store_offset(tree)+i*MTYPE_byte_size(mtype),
>> + st_ofst,
>> WN_st_idx(tree), Be_Type_Tbl(desc), n_rhs);
>> + st_ofst += MTYPE_byte_size(mtype);
>> wn = lower_store (block, wn, actions);
>> WN_Set_Linenum(wn, current_srcpos);
>> }
>> @@ -7394,6 +7396,7 @@
>> }
>> else { // return via 1 or more return registers
>> WN *base_expr;
>> + WN_OFFSET st_ofst = WN_store_offset(tree);
>> for (INT32 i = 0; i < RETURN_INFO_count(return_info); i++) {
>> if (i != 0)
>> WN_INSERT_BlockLast (block, wn); // insert the last STID created
>> @@ -7406,8 +7409,9 @@
>> // OSP-438: The type of Istore node should be a pointer to mtype.
>> // (Previously, we just use Be_Type_Tbl(mtype) as the type of Istore).
>> wn = WN_CreateIstore(OPR_ISTORE, MTYPE_V, mtype,
>> - WN_store_offset(tree)+i*MTYPE_byte_size(mtype),
>> + st_ofst,
>> Make_Pointer_Type(Be_Type_Tbl(mtype),
>> FALSE), n_rhs, base_expr);
>> + st_ofst += MTYPE_byte_size(mtype);
>> WN_Set_Linenum(wn, WN_Get_Linenum(tree));
>> wn = lower_store (block, wn, actions);
>> WN_Set_Linenum (wn, WN_Get_Linenum(tree));
>> @@ -12285,6 +12289,7 @@
>> ("expected RETURN_VAL kid not type M"));
>>
>> algn = TY_align(ty_idx);
>> + WN_OFFSET ld_ofst = WN_load_offset(o_rhs);
>> for (i = 0; i < RETURN_INFO_count(return_info); i++) {
>> mtype = RETURN_INFO_mtype(return_info, i);
>> ty_idx_used = Be_Type_Tbl(mtype);
>> @@ -12312,15 +12317,14 @@
>> #endif
>> #if defined(TARG_PPC32)
>> n_rhs = WN_CreateLdid (OPR_LDID, mtype, desc,
>> - WN_load_offset(o_rhs)
>> - + i * MTYPE_byte_size(mtype),
>> + ld_ofst,
>> WN_st_idx(o_rhs), ty_idx_used);
>> #else
>> n_rhs = WN_CreateLdid (OPR_LDID, mtype, mtype,
>> - WN_load_offset(o_rhs)
>> - + i * MTYPE_byte_size(mtype),
>> + ld_ofst,
>> WN_st_idx(o_rhs), ty_idx_used);
>> #endif
>> + ld_ofst += MTYPE_byte_size(mtype);
>> wn = WN_CreateStid(OPR_STID, MTYPE_V, mtype, preg, preg_st,
>> Be_Type_Tbl(mtype), n_rhs);
>> WN_Set_Linenum(wn, current_srcpos); // Bug 1268
>> @@ -12332,6 +12336,7 @@
>> ("expected RETURN_VAL kid not type M"));
>>
>> algn = TY_align(ty_idx);
>> + WN_OFFSET ld_ofst = WN_load_offset(o_rhs);
>> for (i = 0; i < RETURN_INFO_count(return_info); i++) {
>> mtype = RETURN_INFO_mtype(return_info, i);
>> ty_idx_used = Be_Type_Tbl(mtype);
>> @@ -12340,10 +12345,10 @@
>> n_rhs = WN_kid0(o_rhs);
>> else n_rhs = WN_COPY_Tree(WN_kid0(o_rhs));
>> n_rhs = WN_CreateIload(OPR_ILOAD, mtype, mtype,
>> - WN_load_offset(o_rhs)
>> - + i * MTYPE_byte_size(mtype),
>> + ld_ofst,
>> ty_idx_used,
>> Make_Pointer_Type(ty_idx_used), n_rhs);
>> + ld_ofst += MTYPE_byte_size(mtype);
>> n_rhs = lower_expr(block, n_rhs, actions);
>> preg = RETURN_INFO_preg (return_info, i);
>> preg_st = Standard_Preg_For_Mtype(mtype);
>> @@ -12357,6 +12362,7 @@
>> Is_True(WN_operator(WN_kid1(o_rhs)) == OPR_INTCONST,
>> ("expected RETURN_VAL's MLOAD kid to be of constant size"));
>> algn = TY_align(TY_pointed(WN_load_addr_ty(o_rhs)));
>> + WN_OFFSET ld_ofst = WN_load_offset(o_rhs);
>> for (i = 0; i < RETURN_INFO_count(return_info); i++) {
>> mtype = RETURN_INFO_mtype(return_info, i);
>> ty_idx_used = Be_Type_Tbl(mtype);
>> @@ -12365,10 +12371,10 @@
>> n_rhs = WN_kid0(o_rhs);
>> else n_rhs = WN_COPY_Tree(WN_kid0(o_rhs));
>> n_rhs = WN_CreateIload(OPR_ILOAD, mtype, mtype,
>> - WN_load_offset(o_rhs)
>> - + i * MTYPE_byte_size(mtype),
>> + ld_ofst,
>> ty_idx_used,
>> Make_Pointer_Type(ty_idx_used), n_rhs);
>> + ld_ofst += MTYPE_byte_size(mtype);
>> n_rhs = lower_expr(block, n_rhs, actions);
>> preg = RETURN_INFO_preg (return_info, i);
>> preg_st = Standard_Preg_For_Mtype(mtype);
>> Index: osprey/common/com/x8664/targ_sim.cxx
>> ===================================================================
>> --- osprey/common/com/x8664/targ_sim.cxx (revision 3998)
>> +++ osprey/common/com/x8664/targ_sim.cxx (working copy)
>> @@ -673,13 +673,13 @@
>> }
>> else {
>> if (classes[0] == X86_64_SSE_CLASS) {
>> - info.mtype[0] = SIM_INFO.dbl_type;
>> + info.mtype[0] = (size > 4) ? MTYPE_F8 : MTYPE_F4;
>> info.preg[0] = PR_first_reg(SIM_INFO.dbl_results);
>> next_float_return_num = PR_last_reg(SIM_INFO.dbl_results);
>> next_int_return_num = PR_first_reg(SIM_INFO.int_results);
>> }
>> else {
>> - info.mtype[0] = SIM_INFO.int_type;
>> + info.mtype[0] = (size > 4) ? MTYPE_I8 : MTYPE_I4;
>> info.preg[0] = PR_first_reg(SIM_INFO.int_results);
>> next_float_return_num = PR_first_reg(SIM_INFO.dbl_results);
>> next_int_return_num = PR_last_reg(SIM_INFO.int_results);
>> @@ -687,11 +687,11 @@
>>
>> if (n > 1) {
>> if (classes[1] == X86_64_SSE_CLASS) {
>> - info.mtype[1] = SIM_INFO.dbl_type;
>> + info.mtype[1] = (size > 12) ? MTYPE_F8 : MTYPE_F4;
>> info.preg[1] = next_float_return_num;
>> }
>> else {
>> - info.mtype[1] = SIM_INFO.int_type;
>> + info.mtype[1] = (size > 12) ? MTYPE_I8 : MTYPE_I4;
>> info.preg[1] = next_int_return_num;
>> }
>> }
>>
>>
>> --
>> Regards,
>> Lai Jian-Xin
>>
>> ------------------------------------------------------------------------------
>> Live Security Virtual Conference
>> Exclusive live event will cover all the ways today's security and
>> threat landscape has changed and how IT managers can respond. Discussions
>> will include endpoint security, mobile security and the latest in malware
>> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
>> _______________________________________________
>> Open64-devel mailing list
>> Open64-devel@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/open64-devel
--
Regards,
Lai Jian-Xin
------------------------------------------------------------------------------
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