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概要[]
865 /* Create the DECL_RTL for a VAR_DECL or FUNCTION_DECL. DECL should 866 have static storage duration. In other words, it should not be an 867 automatic variable, including PARM_DECLs. 868 869 There is, however, one exception: this function handles variables 870 explicitly placed in a particular register by the user. 871 872 This is never called for PARM_DECL nodes. */
引数[]
- tree decl
- 宣言の構文木
実装[]
874 void
875 make_decl_rtl (tree decl)
876 {
877 const char *name = 0;
878 int reg_number;
879 rtx x;
880
881 /* Check that we are not being given an automatic variable. */
882 gcc_assert (TREE_CODE (decl) != PARM_DECL
883 && TREE_CODE (decl) != RESULT_DECL);
884
885 /* A weak alias has TREE_PUBLIC set but not the other bits. */
886 gcc_assert (TREE_CODE (decl) != VAR_DECL
887 || TREE_STATIC (decl)
888 || TREE_PUBLIC (decl)
889 || DECL_EXTERNAL (decl)
890 || DECL_REGISTER (decl));
891
892 /* And that we were not given a type or a label. */
893 gcc_assert (TREE_CODE (decl) != TYPE_DECL
894 && TREE_CODE (decl) != LABEL_DECL);
895
896 /* For a duplicate declaration, we can be called twice on the
897 same DECL node. Don't discard the RTL already made. */
898 if (DECL_RTL_SET_P (decl))
899 {
900 /* If the old RTL had the wrong mode, fix the mode. */
901 if (GET_MODE (DECL_RTL (decl)) != DECL_MODE (decl))
902 SET_DECL_RTL (decl, adjust_address_nv (DECL_RTL (decl),
903 DECL_MODE (decl), 0));
904
905 if (TREE_CODE (decl) != FUNCTION_DECL && DECL_REGISTER (decl))
906 return;
907
908 /* ??? Another way to do this would be to maintain a hashed
909 table of such critters. Instead of adding stuff to a DECL
910 to give certain attributes to it, we could use an external
911 hash map from DECL to set of attributes. */
912
913 /* Let the target reassign the RTL if it wants.
914 This is necessary, for example, when one machine specific
915 decl attribute overrides another. */
916 targetm.encode_section_info (decl, DECL_RTL (decl), false);
917
918 /* Make this function static known to the mudflap runtime. */
919 if (flag_mudflap && TREE_CODE (decl) == VAR_DECL)
920 mudflap_enqueue_decl (decl);
921
922 return;
923 }
924
925 name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
926
927 if (name[0] != '*' && TREE_CODE (decl) != FUNCTION_DECL
928 && DECL_REGISTER (decl))
929 {
930 error ("register name not specified for %q+D", decl);
931 }
932 else if (TREE_CODE (decl) != FUNCTION_DECL && DECL_REGISTER (decl))
933 {
934 const char *asmspec = name+1;
935 reg_number = decode_reg_name (asmspec);
936 /* First detect errors in declaring global registers. */
937 if (reg_number == -1)
938 error ("register name not specified for %q+D", decl);
939 else if (reg_number < 0)
940 error ("invalid register name for %q+D", decl);
941 else if (TYPE_MODE (TREE_TYPE (decl)) == BLKmode)
942 error ("data type of %q+D isn%'t suitable for a register",
943 decl);
944 else if (! HARD_REGNO_MODE_OK (reg_number, TYPE_MODE (TREE_TYPE (decl))))
945 error ("register specified for %q+D isn%'t suitable for data type",
946 decl);
947 /* Now handle properly declared static register variables. */
948 else
949 {
950 int nregs;
951
952 if (DECL_INITIAL (decl) != 0 && TREE_STATIC (decl))
953 {
954 DECL_INITIAL (decl) = 0;
955 error ("global register variable has initial value");
956 }
957 if (TREE_THIS_VOLATILE (decl))
958 warning (OPT_Wvolatile_register_var,
959 "optimization may eliminate reads and/or "
960 "writes to register variables");
961
962 /* If the user specified one of the eliminables registers here,
963 e.g., FRAME_POINTER_REGNUM, we don't want to get this variable
964 confused with that register and be eliminated. This usage is
965 somewhat suspect... */
66
967 SET_DECL_RTL (decl, gen_rtx_raw_REG (DECL_MODE (decl), reg_number));
968 ORIGINAL_REGNO (DECL_RTL (decl)) = reg_number;
969 REG_USERVAR_P (DECL_RTL (decl)) = 1;
970
971 if (TREE_STATIC (decl))
972 {
973 /* Make this register global, so not usable for anything
974 else. */
975 #ifdef ASM_DECLARE_REGISTER_GLOBAL
976 name = IDENTIFIER_POINTER (DECL_NAME (decl));
977 ASM_DECLARE_REGISTER_GLOBAL (asm_out_file, decl, reg_number, name);
978 #endif
979 nregs = hard_regno_nregs[reg_number][DECL_MODE (decl)];
980 while (nregs > 0)
981 globalize_reg (reg_number + --nregs);
982 }
983
984 /* As a register variable, it has no section. */
985 return;
986 }
987 }
988 /* Now handle ordinary static variables and functions (in memory).
989 Also handle vars declared register invalidly. */
990 else if (name[0] == '*')
991 {
992 #ifdef REGISTER_PREFIX
993 if (strlen (REGISTER_PREFIX) != 0)
994 {
995 reg_number = decode_reg_name (name);
996 if (reg_number >= 0 || reg_number == -3)
997 error ("register name given for non-register variable %q+D", decl);
998 }
999 #endif
1000 }
1001
1002 /* Specifying a section attribute on a variable forces it into a
1003 non-.bss section, and thus it cannot be common. */
1004 if (TREE_CODE (decl) == VAR_DECL
1005 && DECL_SECTION_NAME (decl) != NULL_TREE
1006 && DECL_INITIAL (decl) == NULL_TREE
1007 && DECL_COMMON (decl))
1008 DECL_COMMON (decl) = 0;
1009
1010 /* Variables can't be both common and weak. */
1011 if (TREE_CODE (decl) == VAR_DECL && DECL_WEAK (decl))
1012 DECL_COMMON (decl) = 0;
1013
1014 x = gen_rtx_SYMBOL_REF (Pmode, name);
1015 SYMBOL_REF_WEAK (x) = DECL_WEAK (decl);
1016 SYMBOL_REF_DECL (x) = decl;
1017
1018 x = gen_rtx_MEM (DECL_MODE (decl), x);
1019 if (TREE_CODE (decl) != FUNCTION_DECL)
1020 set_mem_attributes (x, decl, 1);
1021 SET_DECL_RTL (decl, x);
1022
1023 /* Optionally set flags or add text to the name to record information
1024 such as that it is a function name.
1025 If the name is changed, the macro ASM_OUTPUT_LABELREF
1026 will have to know how to strip this information. */
1027 targetm.encode_section_info (decl, DECL_RTL (decl), true);
1028
1029 /* Make this function static known to the mudflap runtime. */
1030 if (flag_mudflap && TREE_CODE (decl) == VAR_DECL)
1031 mudflap_enqueue_decl (decl);
1032