From 78f8b4242f36d38b74867184a5a926f4b47f42bd Mon Sep 17 00:00:00 2001 From: Jim Blandy Date: Tue, 13 Nov 2001 17:47:19 +0000 Subject: [PATCH] * s390-tdep.c: Rewrite inferior function call code. This may break zSeries support; that should be fixed soon. #include "gdb_assert.h". (is_integer_like, is_pointer_like, is_simple_arg, pass_by_copy_ref, extend_simple_arg, is_double_arg, round_up, round_down, alignment_of): New functions. (s390_push_arguments): Rewritten to handle passing large arguments by value, and to make more readable. --- gdb/ChangeLog | 9 ++ gdb/s390-tdep.c | 423 +++++++++++++++++++++++++++++++++++++----------- 2 files changed, 334 insertions(+), 98 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index e6bdf29f8a..fdac70066b 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,5 +1,14 @@ 2001-11-13 Jim Blandy + * s390-tdep.c: Rewrite inferior function call code. This may + break zSeries support; that should be fixed soon. + #include "gdb_assert.h". + (is_integer_like, is_pointer_like, is_simple_arg, + pass_by_copy_ref, extend_simple_arg, is_double_arg, round_up, + round_down, alignment_of): New functions. + (s390_push_arguments): Rewritten to handle passing large arguments + by value, and to make more readable. + * s390-tdep.c (s390_pop_frame): Call generic_pop_current_frame, to interact correctly with generic dummy frames. (s390_pop_frame_regular): Move the guts of the frame-popping code diff --git a/gdb/s390-tdep.c b/gdb/s390-tdep.c index 32e5ef1a7a..7389637fb4 100644 --- a/gdb/s390-tdep.c +++ b/gdb/s390-tdep.c @@ -36,7 +36,7 @@ #include "floatformat.h" #include "regcache.h" #include "value.h" - +#include "gdb_assert.h" @@ -1199,116 +1199,343 @@ s390_pop_frame () } -/* used by call function by hand - struct_return indicates that this function returns a structure & - therefore gpr2 stores a pointer to the structure to be returned as - opposed to the first argument. - Currently I haven't seen a TYPE_CODE_INT whose size wasn't 2^n or less - than S390_GPR_SIZE this is good because I don't seem to have to worry - about sign extending pushed arguments (i.e. a signed char currently - comes into this code with a size of 4 ). */ +/* Return non-zero if TYPE is an integer-like type, zero otherwise. + "Integer-like" types are those that should be passed the way + integers are: integers, enums, ranges, characters, and booleans. */ +static int +is_integer_like (struct type *type) +{ + enum type_code code = TYPE_CODE (type); + + return (code == TYPE_CODE_INT + || code == TYPE_CODE_ENUM + || code == TYPE_CODE_RANGE + || code == TYPE_CODE_CHAR + || code == TYPE_CODE_BOOL); +} + + +/* Return non-zero if TYPE is a pointer-like type, zero otherwise. + "Pointer-like" types are those that should be passed the way + pointers are: pointers and references. */ +static int +is_pointer_like (struct type *type) +{ + enum type_code code = TYPE_CODE (type); + + return (code == TYPE_CODE_PTR + || code == TYPE_CODE_REF); +} + + +/* Return non-zero if TYPE is considered a `DOUBLE_OR_FLOAT', as + defined by the parameter passing conventions described in the + "Linux for S/390 ELF Application Binary Interface Supplement". + Otherwise, return zero. */ +static int +is_double_or_float (struct type *type) +{ + return (TYPE_CODE (type) == TYPE_CODE_FLT + && (TYPE_LENGTH (type) == 4 + || TYPE_LENGTH (type) == 8)); +} + +/* Return non-zero if TYPE is considered a `SIMPLE_ARG', as defined by + the parameter passing conventions described in the "Linux for S/390 + ELF Application Binary Interface Supplement". Return zero otherwise. */ +static int +is_simple_arg (struct type *type) +{ + enum type_code code = TYPE_CODE (type); + unsigned length = TYPE_LENGTH (type); + + return ((is_integer_like (type) && length <= 4) + || is_pointer_like (type) + || code == TYPE_CODE_STRUCT + || code == TYPE_CODE_UNION + || (code == TYPE_CODE_FLT && length == 16)); +} + + +/* Return non-zero if TYPE should be passed as a pointer to a copy, + zero otherwise. TYPE must be a SIMPLE_ARG, as recognized by + `is_simple_arg'. */ +static int +pass_by_copy_ref (struct type *type) +{ + enum type_code code = TYPE_CODE (type); + unsigned length = TYPE_LENGTH (type); + + return (((code == TYPE_CODE_STRUCT || code == TYPE_CODE_UNION) + && length != 1 && length != 2 && length != 4) + || (code == TYPE_CODE_FLT && length == 16)); +} + + +/* Return ARG, a `SIMPLE_ARG', sign-extended or zero-extended to a full + word as required for the ABI. */ +static LONGEST +extend_simple_arg (struct value *arg) +{ + struct type *type = VALUE_TYPE (arg); + + /* Even structs get passed in the least significant bits of the + register / memory word. It's not really right to extract them as + an integer, but it does take care of the extension. */ + if (TYPE_UNSIGNED (type)) + return extract_unsigned_integer (VALUE_CONTENTS (arg), + TYPE_LENGTH (type)); + else + return extract_signed_integer (VALUE_CONTENTS (arg), + TYPE_LENGTH (type)); +} + + +/* Return non-zero if TYPE is a `DOUBLE_ARG', as defined by the + parameter passing conventions described in the "Linux for S/390 ELF + Application Binary Interface Supplement". Return zero otherwise. */ +static int +is_double_arg (struct type *type) +{ + enum type_code code = TYPE_CODE (type); + unsigned length = TYPE_LENGTH (type); + + return ((is_integer_like (type) + || code == TYPE_CODE_STRUCT + || code == TYPE_CODE_UNION) + && length == 8); +} + + +/* Round ADDR up to the next N-byte boundary. N must be a power of + two. */ +static CORE_ADDR +round_up (CORE_ADDR addr, int n) +{ + /* Check that N is really a power of two. */ + gdb_assert (n && (n & (n-1)) == 0); + return ((addr + n - 1) & -n); +} + + +/* Round ADDR down to the next N-byte boundary. N must be a power of + two. */ +static CORE_ADDR +round_down (CORE_ADDR addr, int n) +{ + /* Check that N is really a power of two. */ + gdb_assert (n && (n & (n-1)) == 0); + return (addr & -n); +} + + +/* Return the alignment required by TYPE. */ +static int +alignment_of (struct type *type) +{ + int alignment; + + if (is_integer_like (type) + || is_pointer_like (type) + || TYPE_CODE (type) == TYPE_CODE_FLT) + alignment = TYPE_LENGTH (type); + else if (TYPE_CODE (type) == TYPE_CODE_STRUCT + || TYPE_CODE (type) == TYPE_CODE_UNION) + { + int i; + + alignment = 1; + for (i = 0; i < TYPE_NFIELDS (type); i++) + { + int field_alignment = alignment_of (TYPE_FIELD_TYPE (type, i)); + + if (field_alignment > alignment) + alignment = field_alignment; + } + } + else + alignment = 1; + + /* Check that everything we ever return is a power of two. Lots of + code doesn't want to deal with aligning things to arbitrary + boundaries. */ + gdb_assert ((alignment & (alignment - 1)) == 0); + + return alignment; +} + + +/* Put the actual parameter values pointed to by ARGS[0..NARGS-1] in + place to be passed to a function, as specified by the "Linux for + S/390 ELF Application Binary Interface Supplement". + + SP is the current stack pointer. We must put arguments, links, + padding, etc. whereever they belong, and return the new stack + pointer value. + + If STRUCT_RETURN is non-zero, then the function we're calling is + going to return a structure by value; STRUCT_ADDR is the address of + a block we've allocated for it on the stack. + + Our caller has taken care of any type promotions needed to satisfy + prototypes or the old K&R argument-passing rules. */ CORE_ADDR s390_push_arguments (int nargs, struct value **args, CORE_ADDR sp, int struct_return, CORE_ADDR struct_addr) { - int num_float_args, num_gpr_args, orig_num_gpr_args, argno; - int second_pass, len, arglen, gprs_required; - CORE_ADDR outgoing_args_ptr, outgoing_args_space; - struct value *arg; - struct type *type; - int max_num_gpr_args = 5 - (struct_return ? 1 : 0); - int arg0_regnum = S390_GP0_REGNUM + 2 + (struct_return ? 1 : 0); - char *reg_buff = alloca (max (S390_FPR_SIZE, REGISTER_SIZE)), *value; + int i; + int pointer_size = (TARGET_PTR_BIT / TARGET_CHAR_BIT); - for (second_pass = 0; second_pass <= 1; second_pass++) - { - if (second_pass) - outgoing_args_ptr = sp + S390_STACK_FRAME_OVERHEAD; - else - outgoing_args_ptr = 0; - num_float_args = 0; - num_gpr_args = 0; - for (argno = 0; argno < nargs; argno++) - { - arg = args[argno]; - type = check_typedef (VALUE_TYPE (arg)); - len = TYPE_LENGTH (type); - if (TYPE_CODE (type) == TYPE_CODE_FLT) - { - int all_float_registers_used = - num_float_args > (GDB_TARGET_IS_ESAME ? 3 : 1); + /* The number of arguments passed by reference-to-copy. */ + int num_copies; - if (second_pass) - { - DOUBLEST tempfloat = - extract_floating (VALUE_CONTENTS (arg), len); - - - floatformat_from_doublest (all_float_registers_used && - len == (TARGET_FLOAT_BIT >> 3) - ? &floatformat_ieee_single_big - : &floatformat_ieee_double_big, - &tempfloat, reg_buff); - if (all_float_registers_used) - write_memory (outgoing_args_ptr, reg_buff, len); - else - write_register_bytes (REGISTER_BYTE ((S390_FP0_REGNUM) - + - (2 * - num_float_args)), - reg_buff, S390_FPR_SIZE); - } - if (all_float_registers_used) - outgoing_args_ptr += len; - num_float_args++; - } - else - { - gprs_required = ((len + (S390_GPR_SIZE - 1)) / S390_GPR_SIZE); + /* If the i'th argument is passed as a reference to a copy, then + copy_addr[i] is the address of the copy we made. */ + CORE_ADDR *copy_addr = alloca (nargs * sizeof (CORE_ADDR)); - value = - s390_promote_integer_argument (type, VALUE_CONTENTS (arg), - reg_buff, &arglen); + /* Build the reference-to-copy area. */ + num_copies = 0; + for (i = 0; i < nargs; i++) + { + struct value *arg = args[i]; + struct type *type = VALUE_TYPE (arg); + unsigned length = TYPE_LENGTH (type); - orig_num_gpr_args = num_gpr_args; - num_gpr_args += gprs_required; - if (num_gpr_args > max_num_gpr_args) - { - if (second_pass) - write_memory (outgoing_args_ptr, value, arglen); - outgoing_args_ptr += arglen; - } - else - { - if (second_pass) - write_register_bytes (REGISTER_BYTE (arg0_regnum) - + - (orig_num_gpr_args * S390_GPR_SIZE), - value, arglen); - } - } - } - if (second_pass) + if (is_simple_arg (type) + && pass_by_copy_ref (type)) { - /* Write the back chain pointer into the first word of the - stack frame. This will help us get backtraces from - within functions called from GDB. */ - write_memory_unsigned_integer (sp, - (TARGET_PTR_BIT / TARGET_CHAR_BIT), - read_fp ()); + sp -= length; + sp = round_down (sp, alignment_of (type)); + write_memory (sp, VALUE_CONTENTS (arg), length); + copy_addr[i] = sp; + num_copies++; } - else - { - outgoing_args_space = outgoing_args_ptr; - /* Align to 16 bytes because because I like alignment & - some of the kernel code requires 8 byte stack alignment at least. */ - sp = (sp - (S390_STACK_FRAME_OVERHEAD + outgoing_args_ptr)) & (-16); - } - } - return sp; + /* Reserve space for the parameter area. As a conservative + simplification, we assume that everything will be passed on the + stack. */ + { + int i; + + for (i = 0; i < nargs; i++) + { + struct value *arg = args[i]; + struct type *type = VALUE_TYPE (arg); + int length = TYPE_LENGTH (type); + + sp = round_down (sp, alignment_of (type)); + + /* SIMPLE_ARG values get extended to 32 bits. Assume every + argument is. */ + if (length < 4) length = 4; + sp -= length; + } + } + + /* Include space for any reference-to-copy pointers. */ + sp = round_down (sp, pointer_size); + sp -= num_copies * pointer_size; + + /* After all that, make sure it's still aligned on an eight-byte + boundary. */ + sp = round_down (sp, 8); + + /* Finally, place the actual parameters, working from SP towards + higher addresses. The code above is supposed to reserve enough + space for this. */ + { + int fr = 0; + int gr = 2; + CORE_ADDR starg = sp; + + for (i = 0; i < nargs; i++) + { + struct value *arg = args[i]; + struct type *type = VALUE_TYPE (arg); + + if (is_double_or_float (type) + && fr <= 2) + { + /* When we store a single-precision value in an FP register, + it occupies the leftmost bits. */ + write_register_bytes (REGISTER_BYTE (S390_FP0_REGNUM + fr), + VALUE_CONTENTS (arg), + TYPE_LENGTH (type)); + fr += 2; + } + else if (is_simple_arg (type) + && gr <= 6) + { + /* Do we need to pass a pointer to our copy of this + argument? */ + if (pass_by_copy_ref (type)) + write_register (S390_GP0_REGNUM + gr, copy_addr[i]); + else + write_register (S390_GP0_REGNUM + gr, extend_simple_arg (arg)); + + gr++; + } + else if (is_double_arg (type) + && gr <= 5) + { + write_register_gen (S390_GP0_REGNUM + gr, + VALUE_CONTENTS (arg)); + write_register_gen (S390_GP0_REGNUM + gr + 1, + VALUE_CONTENTS (arg) + 4); + gr += 2; + } + else + { + /* The `OTHER' case. */ + enum type_code code = TYPE_CODE (type); + unsigned length = TYPE_LENGTH (type); + + /* If we skipped r6 because we couldn't fit a DOUBLE_ARG + in it, then don't go back and use it again later. */ + if (is_double_arg (type) && gr == 6) + gr = 7; + + if (is_simple_arg (type)) + { + /* Simple args are always either extended to 32 bits, + or pointers. */ + starg = round_up (starg, 4); + + /* Do we need to pass a pointer to our copy of this + argument? */ + if (pass_by_copy_ref (type)) + write_memory_signed_integer (starg, pointer_size, + copy_addr[i]); + else + /* Simple args are always extended to 32 bits. */ + write_memory_signed_integer (starg, 4, + extend_simple_arg (arg)); + starg += 4; + } + else + { + starg = round_up (starg, alignment_of (type)); + write_memory (starg, VALUE_CONTENTS (arg), length); + starg += length; + } + } + } + } + + /* Allocate the standard frame areas: the register save area, the + word reserved for the compiler (which seems kind of meaningless), + and the back chain pointer. */ + sp -= 96; + + /* Write the back chain pointer into the first word of the stack + frame. This will help us get backtraces from within functions + called from GDB. */ + write_memory_unsigned_integer (sp, (TARGET_PTR_BIT / TARGET_CHAR_BIT), + read_fp ()); + + return sp; } /* Return the GDB type object for the "standard" data type -- 2.34.1