[M3devel] m3_load/m3_store/bit_field_ref lose offset??

Sun Nov 9 12:10:54 CET 2008

I agree. I am suspicious too. I will investigate more. Thanks.

 - Jay

From: hosking at cs.purdue.eduTo: jay.krell at cornell.eduDate: Sun, 9 Nov 2008 10:01:58 +0000CC: m3devel at elegosoft.comSubject: Re: [M3devel] m3_load/m3_store/bit_field_ref lose offset??
Aren't the integer values supposed to be written endian-independently in the IR?  I am suspicious about these differences.

On 9 Nov 2008, at 01:25, Jay wrote:

Thanks for the tip/direction. Uncertain -- m3cgcat between AMD64_LINUX and MIPS64_OPENBSD are "the same" but for two systematic diffs:  - AMD64_LINUX has a bunch of added calls to check_nil.   This is a "bug" in it, inoptimal but ok code, because "first readable address" is 0. It should probably be 4k. I should write a program that iterates starting at 0 to find the value.  (or better yet, cm3 should have a -configure option that does this? -- for configuration values for which there is a safe default; in general, imho, the targets should be auto configured via C, assuming there is a native development environment available).  - some integers are different (again, systematically)  AMD64_LINUX: init_int  656 13 Int.64 init_chars  664 "    typecode " init_int  680 2 Int.64 init_var  688 v.1 0 init_int  696 13 Int.64 init_chars  704 "    typeid   " init_int  720 2 Int.64 init_var  728 v.1 0 init_int  736 13 Int.64 init_chars  744 "RunMainBody: " init_int  760 2 Int.64 init_var  768 v.1 0 init_int  776 19 Int.64 init_chars  784 "RunMainBody: exec: " init_int  808 2 Int.64 init_var  816 v.1 0 init_int  824 17 Int.64 init_chars  832 "ExpandInitStack: "MIPS64_OPENBSD:  init_chars  664 "    typecode " init_int  680 8796093022208 Int.64 init_var  688 v.1 0 init_int  696 13 Int.64 init_chars  704 "    typeid   " init_int  720 8796093022208 Int.64 init_var  728 v.1 0 init_int  736 13 Int.64 init_chars  744 "RunMainBody: " init_int  760 8796093022208 Int.64 init_var  768 v.1 0 init_int  776 19 Int.64 init_chars  784 "RunMainBody: exec: " init_int  808 8796093022208 Int.64 init_var  816 v.1 0This 8796093022208 is 80000000000 aka 0000_0800_0000_0000, where little endian has 2. I don't know what these numbers represent.I should look at other systems -- preferably a working 64 bit big endian system, if there are any. Could be flags/type with text literals? (Btw, I always leave the TextLiteral.i3 change on my system, lowering the maximum literal length to around 4gig even on 64 bit targets, so 32 bit can bootstrap 64 bit...need to fix the compiler here to do target arithmetic instead of host arithmetic...) Thanks, - Jay

From: hosking at cs.purdue.eduTo: jay.krell at cornell.eduDate: Sat, 8 Nov 2008 22:55:54 +0000CC: m3devel at elegosoft.comSubject: Re: [M3devel] m3_load/m3_store/bit_field_ref lose offset??Have you checked to make sure that the pre-gcc IR makes sense?  Does it see these values as 32-bit or 64-bit?  The reason I ask is that there may be something wrong in your m3middle target specs that cause bad IR.  Once we know the IR looks right then we can try and fix the problem.

Antony Hosking | Associate Professor | Computer Science | Purdue University
305 N. University Street | West Lafayette | IN 47907 | USA
Office +1 765 494 6001 | Mobile +1 765 427 5484

On 8 Nov 2008, at 15:45, Jay wrote:

truncated as usual...along with losing a lot of whitespace..Let's see...Tony, how about switching these #if's?I explain some of why below.static voidm3_store (tree v, int o, tree src_t, m3_type src_T, tree dst_t, m3_type dst_T){ tree val;#if 0 if (o != 0 || TREE_TYPE (v) != dst_t) {   v = m3_build3 (BIT_FIELD_REF, dst_t, v, TYPE_SIZE (dst_t),    bitsize_int (o)); }#else /* failsafe, but inefficient */ if (o != 0 || TREE_TYPE (v) != dst_t) {   v = m3_build1 (ADDR_EXPR, t_addr, v);   v = m3_build2 (PLUS_EXPR, t_addr, v, size_int (o / BITS_PER_UNIT));   v = m3_build1 (INDIRECT_REF, dst_t,    m3_cast (build_pointer_type (dst_t), v)); }#endif TREE_THIS_VOLATILE (v) = 1; /* force this to avoid aliasing problems */ val = m3_cast (src_t, EXPR_REF (-1)); if (src_T != dst_T) {   val = m3_build1 (CONVERT_EXPR, dst_t, val); } add_stmt (build2 (MODIFY_EXPR, dst_t, v, val)); EXPR_POP ();}m3_load (tree v, int o, tree src_t, m3_type src_T, tree dst_t, m3_type dst_T){#if 0 if (o != 0 || TREE_TYPE (v) != src_t) {   v = m3_build3 (BIT_FIELD_REF, src_t, v, TYPE_SIZE (src_t),    bitsize_int (o)); }#else /* failsafe, but inefficient */ if (o != 0 || TREE_TYPE (v) != src_t) {   v = m3_build1 (ADDR_EXPR, t_addr, v);   v = m3_build2 (PLUS_EXPR, t_addr, v, size_int (o / BITS_PER_UNIT));   v = m3_build1 (INDIRECT_REF, src_t,    m3_cast (build_pointer_type (src_t), v)); }#endif TREE_THIS_VOLATILE (v) = 1; /* force this to avoid aliasing problems */ if (src_T != dst_T) {   v = m3_build1 (CONVERT_EXPR, dst_t, v); } EXPR_PUSH (v);}I'm working on MIPS64_OPENBSD (OpenBSD on an SGI O2).In an early version it seems that many loads/stores of global variables is wrong.The "first" code affected is RTLinker_ExpandModuleTable.PROCEDURE ExpandModuleTable () = CONST InitialTableSize = 500; VAR new_mods: ADDRESS;  n_bytes: INTEGER; BEGIN   IF (modules = NIL) THEN     (* first time... *)     max_modules := InitialTableSize;     modules := Cstdlib.malloc (InitialTableSize * BYTESIZE (RT0.ModulePtr));     IF (modules = NIL) THEN Cstdlib.abort (); END;   ELSE     n_bytes := max_modules * BYTESIZE (RT0.ModulePtr);     new_mods := Cstdlib.malloc (n_bytes + n_bytes);     IF (new_mods = NIL) THEN Cstdlib.abort (); END;     EVAL Cstring.memcpy (new_mods, modules, n_bytes);     Cstdlib.free (modules);     modules := new_mods;     INC (max_modules, max_modules);   END; END ExpandModuleTable;It should read back modules as NIL.What happens is it reads back modules as not NIL,and then max_modules should also be zero, but is "large", leading to malloc to fail,and abort called.The output of cm3cg -y is reasonable.It indicates offset loads.What is incorrect is that in many loads and stores, but not all, theoffsets are lost.(923) begin_procedure procedure RTLinker__ExpandModuleTableRTLinker__ExpandModuleTable(924) set_source_line source line  208(925) load_nil(926) store store (M3_AJWxb1_new_mods) offset 0x0 src_t 0xb dst_t 0xb(927) set_source_line source line  207(928) set_source_line source line  210(929) load_nil(930) load m3cg_load (MM_RTLinker): offset 0x440, convert 0xb -> 0xbHere is the incorrect code:.globl RTLinker__ExpandModuleTable.stabd 46,0,0.stabn 68,0,206,.LM108.LM108:.LFBB8:.set nomips16.ent RTLinker__ExpandModuleTableRTLinker__ExpandModuleTable:.frame $fp,64,$31  # vars= 32, regs= 3/0, args= 0, gp= 0.mask 0xd0000000,-8.fmask 0x00000000,0daddiu $sp,$sp,-64sd $31,56($sp)sd $fp,48($sp)sd $28,40($sp)move $fp,$splui $28,%hi(%neg(%gp_rel(RTLinker__ExpandModuleTable)))daddu $28,$28,$25daddiu $28,$28,%lo(%neg(%gp_rel(RTLinker__ExpandModuleTable))).LBB9:.stabn 68,0,208,.LM109.LM109:sd $0,16($fp).stabn 68,0,210,.LM110.LM110:dla $2,MM_RTLinkerld $2,0($2)      << WRONGbne $2,$0,.L61.stabn 68,0,212,.LM111.LM111:dla $3,MM_RTLinkerld $2,128($3)andi $2,$2,0x0ori $2,$2,0x1f4sd $2,128($3).stabn 68,0,213,.LM112.LM112:li $4,4000   # 0xfa0jal mallocsd $2,0($fp)ld $4,0($fp)dla $3,MM_RTLinkerld $2,136($3)andi $2,$2,0x0or $2,$4,$2sd $2,136($3)     << OK, offset seems low, but it agrees with elsewhere .stabn 68,0,214,.LM113.LM113:dla $2,MM_RTLinkerld $2,0($2)       << WRONG bne $2,$0,.L65jal abortb .L65.L61:.stabn 68,0,216,.LM114.LM114:dla $2,MM_RTLinkerld $2,0($2)        << WRONG dsll $2,$2,3sd $2,8($fp).stabn 68,0,217,.LM115.LM115:ld $3,8($fp)ld $2,8($fp)daddu $2,$3,$2move $4,$2jal mallocsd $2,0($fp)ld $2,0($fp)sd $2,16($fp).stabn 68,0,218,.LM116.LM116:ld $2,16($fp)bne $2,$0,.L64jal abort.L64:.stabn 68,0,219,.LM117.LM117:ld $4,16($fp)dla $2,MM_RTLinkerld $2,0($2)          << WRONGld $3,8($fp)move $5,$2move $6,$3jal memcpysd $2,0($fp).stabn 68,0,220,.LM118.LM118:dla $2,MM_RTLinkerld $2,0($2)           << WRONGmove $4,$2jal free.stabn 68,0,221,.LM119.LM119:ld $4,16($fp)dla $3,MM_RTLinkerld $2,136($3)         << OKandi $2,$2,0x0or $2,$4,$2sd $2,136($3)         << OK .stabn 68,0,222,.LM120.LM120:dla $2,MM_RTLinkerld $3,0($2)           << WRONGdla $2,MM_RTLinkerld $2,0($2)           << WRONGdaddu $4,$3,$2dla $3,MM_RTLinkerld $2,128($3)         << OKandi $2,$2,0x0or $2,$2,$4sd $2,128($3)         << OK.L65:.LBE9:.stabn 68,0,224,.LM121.LM121:move $sp,$fpld $31,56($sp)ld $fp,48($sp)ld $28,40($sp)daddiu $sp,$sp,64j $31.end RTLinker__ExpandModuleTableHere is corrected code:RTLinker__ExpandModuleTable:.frame $fp,64,$31  # vars= 32, regs= 3/0, args= 0, gp= 0.mask 0xd0000000,-8.fmask 0x00000000,0daddiu $sp,$sp,-64sd $31,56($sp)sd $fp,48($sp)sd $28,40($sp)move $fp,$splui $28,%hi(%neg(%gp_rel(RTLinker__ExpandModuleTable)))daddu $28,$28,$25daddiu $28,$28,%lo(%neg(%gp_rel(RTLinker__ExpandModuleTable))).LBB9:.stabn 68,0,208,.LM109.LM109:sd $0,16($fp).stabn 68,0,210,.LM110.LM110:dla $2,MM_RTLinkerdaddiu $2,$2,136     << CORRECT (offset seems low, but at least it isn't zero) ld $2,0($2)bne $2,$0,.L61.stabn 68,0,212,.LM111.LM111:dla $2,MM_RTLinkerdaddiu $3,$2,128     << CORRECT li $2,500   # 0x1f4sd $2,0($3).stabn 68,0,213,.LM112.LM112:li $4,4000   # 0xfa0jal mallocsd $2,0($fp)dla $2,MM_RTLinkerdaddiu $3,$2,136      << CORRECT ld $2,0($fp)sd $2,0($3).stabn 68,0,214,.LM113.LM113:dla $2,MM_RTLinkerdaddiu $2,$2,136      << CORRECT ld $2,0($2)bne $2,$0,.L65jal abortb .L65.L61:I still dump core with this change, but I get much further.I have not tested this change at all otherwise -- i.e. on working platforms.I have not debugged through the gcc/m3cg code to see whythe offsets are only sometimes lost, or why other platformshave no problem. Is MIPS's "global pointer" unusual these days?I know SPARC has similar, and all the non-x86, non-AMD64 NT platformshad similar, but that's essentially nothing now (I'm not counting IA64).I know Linux has PLT (procedure linkage table) and GOT (global offset table).Same thing?I haven't looked much at other MIPS ports yet.http://modula3.elegosoft.com/cgi-bin/cvsweb.cgi/cm3/m3-sys/m3cc/gcc/gcc/m3cg/parse.c.diff?r1=1.7;r2=1.8is what made it look about like it does -- in particularing using BIT_FIELD_REF.1.7:static void m3_load (v, o, src_t, src_T, dest_t, dest_T) /* GCC32OK */    tree v;    int o;    tree src_t, dest_t;    m3_type src_T, dest_T;{ if (o == 0 && TREE_TYPE (v) == src_t) {   EXPR_PUSH (v); } else {   tree adr = m3_build1 (ADDR_EXPR, t_addr, v);   if (o != 0) {     adr = m3_build2 (PLUS_EXPR, t_addr, adr, size_int (o / BITS_PER_UNIT));   }   EXPR_PUSH (m3_build1 (INDIRECT_REF, src_t,                         m3_cast (build_pointer_type (src_t), adr))); }#if 1 if (src_T != dest_T) {   EXPR_REF (-1) = m3_build1 (CONVERT_EXPR, dest_t, EXPR_REF (-1)); } if (debug_vars) {   const char *name = "noname";   if (v != 0 && DECL_NAME(v) != 0) {     name = IDENTIFIER_POINTER(DECL_NAME(v));   }   fprintf(stderr, "  m3_load (%s): offset %d, convert %d -> %d\n", name,           o, src_T, dest_T); }#else if (src_T != dest_T) {   if (IS_INTEGER_TYPE(dest_T) && dest_t != t_int) {     EXPR_REF (-1) = m3_build1 (CONVERT_EXPR, t_int, EXPR_REF (-1));   } else if (IS_WORD_TYPE(dest_T) && dest_t != t_word) {     EXPR_REF (-1) = m3_build1 (CONVERT_EXPR, t_word, EXPR_REF (-1));   } else if (IS_INTEGER_TYPE(dest_T) || IS_WORD_TYPE(dest_T)) {     /* okay */   } else {     fatal_error("m3load: cannot convert types: src_t %d dest_t %d\n",                 src_T, dest_T);   } }#endif}static voidm3_store (v, o, src_t, dest_t)  /* GCC32OK */    tree v;    int o;    tree src_t, dest_t;{ tree lhs, rhs; if (TREE_TYPE (EXPR_REF (-1)) == src_t) {   rhs = EXPR_REF (-1); } else {   rhs = m3_cast (src_t, EXPR_REF (-1)); } if (o == 0 && TREE_TYPE (v) == dest_t) {   lhs = v; } else {   tree f = make_node (FIELD_DECL);   TREE_TYPE (f) = dest_t;   DECL_ALIGN (f) = TYPE_ALIGN (dest_t);   DECL_SIZE (f) = TYPE_SIZE (dest_t);   DECL_MODE (f) = TYPE_MODE (dest_t);   DECL_FIELD_OFFSET (f) = size_int (o / BITS_PER_UNIT);   DECL_FIELD_BIT_OFFSET (f) = bitsize_int (o % BITS_PER_UNIT);   DECL_FIELD_CONTEXT (f) = TREE_TYPE (v);   lhs = m3_build2 (COMPONENT_REF, dest_t, v, f); }#if 1   expand_assignment (lhs, m3_build1 (CONVERT_EXPR, dest_t, rhs), 0, 0);#else if (dest_t ==  NULL) {   expand_assignment (lhs, rhs, 0, 0); } else {   expand_assignment (lhs, m3_build1 (CONVERT_EXPR, dest_t, rhs), 0, 0); }#endif EXPR_POP ();}1.8:static voidm3_load (tree v, int o, tree src_t, m3_type src_T, tree dst_t, m3_type dst_T) /* GCC32OK */{ if (o == 0 && TREE_TYPE (v) == src_t) {   EXPR_PUSH (v); } else {   EXPR_PUSH (m3_build3 (BIT_FIELD_REF, src_t, v, TYPE_SIZE (src_t),    bitsize_int (o))); } if (src_T != dst_T) {   EXPR_REF (-1) = m3_build1 (CONVERT_EXPR, dst_t, EXPR_REF (-1)); } if (option_vars_trace) {   const char *name = "noname";   if (v != 0 && DECL_NAME(v) != 0) {     name = IDENTIFIER_POINTER(DECL_NAME(v));   }   fprintf(stderr, "  m3_load (%s): offset %d, convert %d -> %d\n", name,    o, src_T, dst_T); }}static voidm3_store (tree v, int o, tree src_t, tree dst_t)  /* GCC32OK */{ tree lhs, rhs; if (TREE_TYPE (EXPR_REF (-1)) == src_t) {   rhs = EXPR_REF (-1); } else {   rhs = m3_cast (src_t, EXPR_REF (-1)); } if (o == 0 && TREE_TYPE (v) == dst_t) {   lhs = v; } else {   lhs = m3_build3 (BIT_FIELD_REF, dst_t, v, TYPE_SIZE (dst_t),      bitsize_int (o)); } if (src_t != dst_t) {   rhs = m3_build1 (CONVERT_EXPR, dst_t, rhs); } expand_assignment (lhs, rhs, 0, 0); EXPR_POP ();}- Jay<AMD64_LINUX_RTLinker.mc><MIPS64_OPENBSD_RTLinker.mc>
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