2003-10-02 Andrew Cagney * infcmd.c: Include "gdb_assert.h". (print_return_value): When gdbarch_return_value_p, and using struct return, assume that the value is not available. * values.c (register_value_being_returned): Use "gdbarch_return_value" when available. (set_return_value): Ditto. Call internal_error when an unhandled struct or union is encountered. (using_struct_return): Ditto. * defs.h (return_value_convention): Define. * gdbarch.sh (gdbarch_return_value): New predicate method. * gdbarch.h, gdbarch.c: Re-generate Index: doc/ChangeLog 2003-10-02 Andrew Cagney * gdbint.texinfo (Target Architecture Definition): Document gdbarch_return_value. Add cross references from USE_STRUCT_CONVENTION, EXTRACT_RETURN_VALUE, and STORE_RETURN_VALUE, and from/to EXTRACT_STRUCT_VALUE_ADDRESS. Index: defs.h =================================================================== RCS file: /cvs/src/src/gdb/defs.h,v retrieving revision 1.131 diff -u -r1.131 defs.h --- defs.h 19 Sep 2003 16:22:38 -0000 1.131 +++ defs.h 2 Oct 2003 17:31:44 -0000 @@ -230,6 +230,21 @@ AUTO_BOOLEAN_AUTO }; +/* Potential ways that a function can return a value of a given type. */ +enum return_value_convention +{ + /* Where the return value has been squeezed into one or more + registers. */ + RETURN_VALUE_REGISTER_CONVENTION, + /* Commonly known as the "struct return convention". The caller + passes an additional hidden first parameter to the caller. That + parameter contains the address at which the value being returned + should be stored. While typically, and historically, used for + large structs, this is convention is applied to values of many + different types. */ + RETURN_VALUE_STRUCT_CONVENTION +}; + /* the cleanup list records things that have to be undone if an error happens (descriptors to be closed, memory to be freed, etc.) Each link in the chain records a function to call and an Index: gdbarch.sh =================================================================== RCS file: /cvs/src/src/gdb/gdbarch.sh,v retrieving revision 1.274 diff -u -r1.274 gdbarch.sh --- gdbarch.sh 30 Sep 2003 19:12:18 -0000 1.274 +++ gdbarch.sh 2 Oct 2003 17:31:46 -0000 @@ -593,19 +593,33 @@ f:2:ADDRESS_TO_POINTER:void:address_to_pointer:struct type *type, void *buf, CORE_ADDR addr:type, buf, addr:::unsigned_address_to_pointer::0 F:2:INTEGER_TO_ADDRESS:CORE_ADDR:integer_to_address:struct type *type, void *buf:type, buf # -f:2:RETURN_VALUE_ON_STACK:int:return_value_on_stack:struct type *type:type:::generic_return_value_on_stack_not::0 F:2:DEPRECATED_POP_FRAME:void:deprecated_pop_frame:void:- # NOTE: cagney/2003-03-24: Replaced by PUSH_ARGUMENTS. F:2:DEPRECATED_STORE_STRUCT_RETURN:void:deprecated_store_struct_return:CORE_ADDR addr, CORE_ADDR sp:addr, sp -# + +# It has been suggested that this, well actually its predecessor, +# should take the type/value of the function to be called and not the +# return type. This is left as an exercise for the reader. + +M:::enum return_value_convention:return_value:struct type *valtype, struct regcache *regcache, const void *inval, void *outval:valtype, regcache, inval, outval + +# The deprecated methods RETURN_VALUE_ON_STACK, EXTRACT_RETURN_VALUE, +# STORE_RETURN_VALUE and USE_STRUCT_CONVENTION have all been folded +# into RETURN_VALUE. For the moment do not try to fold in +# EXTRACT_STRUCT_VALUE_ADDRESS as, dependant on the ABI, the debug +# info, and the level of effort, it may well be possible to find the +# address of a structure being return on the stack. Someone else can +# make that change. + +f:2:RETURN_VALUE_ON_STACK:int:return_value_on_stack:struct type *type:type:::generic_return_value_on_stack_not::0 f:2:EXTRACT_RETURN_VALUE:void:extract_return_value:struct type *type, struct regcache *regcache, void *valbuf:type, regcache, valbuf:::legacy_extract_return_value::0 f:2:STORE_RETURN_VALUE:void:store_return_value:struct type *type, struct regcache *regcache, const void *valbuf:type, regcache, valbuf:::legacy_store_return_value::0 f:2:DEPRECATED_EXTRACT_RETURN_VALUE:void:deprecated_extract_return_value:struct type *type, char *regbuf, char *valbuf:type, regbuf, valbuf f:2:DEPRECATED_STORE_RETURN_VALUE:void:deprecated_store_return_value:struct type *type, char *valbuf:type, valbuf -# +f:2:USE_STRUCT_CONVENTION:int:use_struct_convention:int gcc_p, struct type *value_type:gcc_p, value_type:::generic_use_struct_convention::0 + F:2:EXTRACT_STRUCT_VALUE_ADDRESS:CORE_ADDR:extract_struct_value_address:struct regcache *regcache:regcache F:2:DEPRECATED_EXTRACT_STRUCT_VALUE_ADDRESS:CORE_ADDR:deprecated_extract_struct_value_address:char *regbuf:regbuf -f:2:USE_STRUCT_CONVENTION:int:use_struct_convention:int gcc_p, struct type *value_type:gcc_p, value_type:::generic_use_struct_convention::0 # F:2:DEPRECATED_FRAME_INIT_SAVED_REGS:void:deprecated_frame_init_saved_regs:struct frame_info *frame:frame F:2:DEPRECATED_INIT_EXTRA_FRAME_INFO:void:deprecated_init_extra_frame_info:int fromleaf, struct frame_info *frame:fromleaf, frame Index: infcmd.c =================================================================== RCS file: /cvs/src/src/gdb/infcmd.c,v retrieving revision 1.95 diff -u -r1.95 infcmd.c --- infcmd.c 2 Oct 2003 04:40:58 -0000 1.95 +++ infcmd.c 2 Oct 2003 17:31:46 -0000 @@ -44,6 +44,7 @@ #include "reggroups.h" #include "block.h" #include +#include "gdb_assert.h" /* Functions exported for general use, in inferior.h: */ @@ -1079,25 +1080,34 @@ ui_out_field_stream (uiout, "return-value", stb); ui_out_text (uiout, "\n"); } - else - { - /* FIXME: 2003-09-27: When returning from a nested inferior - function call, it's possible (with no help from the - architecture vector) to locate and return/print a "struct - return" value. This is just a more complicated case of what - is already being done in in the inferior function call code. - In fact, when inferior function calls are made async, this - will likely be made the norm. */ - /* We cannot determine the contents of the structure because - it is on the stack, and we don't know where, since we did not - initiate the call, as opposed to the call_function_by_hand case */ + /* FIXME: 2003-09-27: When returning from a nested inferior function + call, it's possible (with no help from the architecture vector) + to locate and return/print a "struct return" value. This is just + a more complicated case of what is already being done in in the + inferior function call code. In fact, when inferior function + calls are made async, this will likely be made the norm. */ #ifdef DEPRECATED_VALUE_RETURNED_FROM_STACK - value = 0; +#define DEPRECATED_VALUE_RETURNED_FROM_STACK_P 1 +#else +#define DEPRECATED_VALUE_RETURNED_FROM_STACK_P 0 +#endif + else if (gdbarch_return_value_p (current_gdbarch) + || DEPRECATED_VALUE_RETURNED_FROM_STACK_P) + /* We cannot determine the contents of the structure because it is + on the stack, and we don't know where, since we did not + initiate the call, as opposed to the call_function_by_hand + case. */ + { + gdb_assert (gdbarch_return_value (current_gdbarch, value_type, NULL, NULL, NULL) + == RETURN_VALUE_STRUCT_CONVENTION); ui_out_text (uiout, "Value returned has type: "); ui_out_field_string (uiout, "return-type", TYPE_NAME (value_type)); ui_out_text (uiout, "."); ui_out_text (uiout, " Cannot determine contents\n"); -#else + return; + } + else + { if (EXTRACT_STRUCT_VALUE_ADDRESS_P ()) { CORE_ADDR addr = EXTRACT_STRUCT_VALUE_ADDRESS (stop_registers); @@ -1133,7 +1143,6 @@ value_print (value, stb->stream, 0, Val_no_prettyprint); ui_out_field_stream (uiout, "return-value", stb); ui_out_text (uiout, "\n"); -#endif } } Index: values.c =================================================================== RCS file: /cvs/src/src/gdb/values.c,v retrieving revision 1.59 diff -u -r1.59 values.c --- values.c 2 Oct 2003 04:40:58 -0000 1.59 +++ values.c 2 Oct 2003 17:31:46 -0000 @@ -1216,11 +1216,22 @@ register_value_being_returned (struct type *valtype, struct regcache *retbuf) { struct value *val = allocate_value (valtype); - CHECK_TYPEDEF (valtype); + /* If the function returns void, don't bother fetching the return value. */ - if (TYPE_CODE (valtype) != TYPE_CODE_VOID) - EXTRACT_RETURN_VALUE (valtype, retbuf, VALUE_CONTENTS_RAW (val)); + if (TYPE_CODE (valtype) == TYPE_CODE_VOID) + return val; + + if (gdbarch_return_value_p (current_gdbarch)) + { + gdb_assert (gdbarch_return_value (current_gdbarch, valtype, NULL, NULL, NULL) + == RETURN_VALUE_REGISTER_CONVENTION); + gdbarch_return_value (current_gdbarch, valtype, retbuf, + NULL, VALUE_CONTENTS_RAW (val)); + } + + CHECK_TYPEDEF (valtype); + EXTRACT_RETURN_VALUE (valtype, retbuf, VALUE_CONTENTS_RAW (val)); return val; } @@ -1262,6 +1273,16 @@ if (code == TYPE_CODE_ERROR) error ("Function return type unknown."); + if (gdbarch_return_value_p (current_gdbarch)) + { + /* Probe the architecture for the return-value convention. */ + return (gdbarch_return_value (current_gdbarch, value_type, + NULL, NULL, NULL) + == RETURN_VALUE_STRUCT_CONVENTION); + } + + /* FIXME: cagney/2003-10-01: The below is dead. Instead an + architecture should implement "gdbarch_return_value". */ if (code == TYPE_CODE_STRUCT || code == TYPE_CODE_UNION || code == TYPE_CODE_ARRAY @@ -1284,9 +1305,29 @@ if (code == TYPE_CODE_ERROR) error ("Function return type unknown."); + if (gdbarch_return_value_p (current_gdbarch)) + { + switch (gdbarch_return_value (current_gdbarch, type, NULL, NULL, NULL)) + { + case RETURN_VALUE_REGISTER_CONVENTION: + /* Success. The architecture can deal with it, write it to + the regcache. */ + gdbarch_return_value (current_gdbarch, type, current_regcache, + VALUE_CONTENTS (val), NULL); + return; + case RETURN_VALUE_STRUCT_CONVENTION: + /* Failure. For the moment, assume that it is not possible + to find the location, on the stack, at which the "struct + return" value should be stored. */ + error ("Location of return value unknown"); + } + } + + if (code == TYPE_CODE_STRUCT - || code == TYPE_CODE_UNION) /* FIXME, implement struct return. */ - error ("GDB does not support specifying a struct or union return value."); + || code == TYPE_CODE_UNION) + /* The architecture needs to implement gdbarch_return_value. */ + internal_error (__FILE__, __LINE__, "This architecture does not yet support specifying a struct or union return value."); STORE_RETURN_VALUE (type, current_regcache, VALUE_CONTENTS (val)); } Index: doc/gdbint.texinfo =================================================================== RCS file: /cvs/src/src/gdb/doc/gdbint.texinfo,v retrieving revision 1.171 diff -u -r1.171 gdbint.texinfo --- doc/gdbint.texinfo 30 Sep 2003 19:12:19 -0000 1.171 +++ doc/gdbint.texinfo 2 Oct 2003 17:31:49 -0000 @@ -3186,13 +3186,17 @@ the raw register state @var{regbuf} and copy that, in virtual format, into @var{valbuf}. +This method has been deprecated in favour of @code{gdbarch_return_value} +(@pxref{gdbarch_return_value}). + @item EXTRACT_STRUCT_VALUE_ADDRESS(@var{regbuf}) @findex EXTRACT_STRUCT_VALUE_ADDRESS +@anchor{EXTRACT_STRUCT_VALUE_ADDRESS} When defined, extract from the array @var{regbuf} (containing the raw register state) the @code{CORE_ADDR} at which a function should return its structure value. -If not defined, @code{EXTRACT_RETURN_VALUE} is used. +@xref{gdbarch_return_value}. @item EXTRACT_STRUCT_VALUE_ADDRESS_P() @findex EXTRACT_STRUCT_VALUE_ADDRESS_P @@ -3785,6 +3789,48 @@ Define this to convert sdb register numbers into @value{GDBN} regnums. If not defined, no conversion will be done. +@item enum return_value_convention gdbarch_return_value (struct gdbarch *@var{gdbarch}, struct type *@var{valtype}, struct regcache *@var{regcache}, const void *@var{inval}, void *@var{outval}) +@findex gdbarch_return_value +@anchor{gdbarch_return_value} @value{GDBN} currently recognizes two +function return-value conventions: +@code{RETURN_VALUE_REGISTER_CONVENTION} where the return value is found +in registers; and @code{RETURN_VALUE_STRUCT_CONVENTION} where the return +value is found in memory and the address of that memory location is +passed in as the function's first parameter. + +Given a function with a return-value of type @var{rettype}, return which +return-value convention that function would use. + +If the register convention is being used, and @var{inval} is +non-@code{NULL}, also copy the return-value in @var{inval} into +@var{regcache}. + +If the register convention is being used, and @var{outval} is +non-@code{NULL}, also copy the return value from @var{regcache} into +@var{outval} (@var{regcache} contains a copy of the registers from the +just returned function). + +@xref{EXTRACT_STRUCT_VALUE_ADDRESS}, for a description of how +return-values that use the struct convention are handled. + +@emph{Maintainer note: This method replaces separate predicate, extract, +store methods. By having only one method, the logic needed to determine +the return-value convention need only be implemented in one place. If +@value{GDBN} were written in an @sc{oo} language, this method would +instead return an object that knew how to perform the register +return-value extract and store.} + +@emph{Maintainer note: This method does not take a @var{gcc_p} +parameter, and such a parameter should not be added. If an architecture +that requires per-compiler or per-function information be identified, +then the replacement of @var{rettype} with @code{struct value} +@var{function} should be persued.} + +@emph{Maintainer note: The @var{regcache} parameter limits this methods +to the inner most frame. While replacing @var{regcache} with a +@code{struct frame_info} @var{frame} parameter would remove that +limitation there has yet to be a demonstrated need for such a change.} + @item SKIP_PERMANENT_BREAKPOINT @findex SKIP_PERMANENT_BREAKPOINT Advance the inferior's PC past a permanent breakpoint. @value{GDBN} normally @@ -3843,6 +3889,9 @@ @var{valbuf}, into the @var{regcache}. @var{type} is the type of the value that is to be returned. +This method has been deprecated in favour of @code{gdbarch_return_value} +(@pxref{gdbarch_return_value}). + @item SUN_FIXED_LBRAC_BUG @findex SUN_FIXED_LBRAC_BUG (Used only for Sun-3 and Sun-4 targets.) @@ -3977,6 +4026,9 @@ being considered is known to have been compiled by GCC; this is helpful for systems where GCC is known to use different calling convention than other compilers. + +This method has been deprecated in favour of @code{gdbarch_return_value} +(@pxref{gdbarch_return_value}). @item VALUE_TO_REGISTER(@var{type}, @var{regnum}, @var{from}, @var{to}) @findex VALUE_TO_REGISTER