#include "regcache.h"
#include "value.h"
#include "gdb_string.h"
-
+#include "gdb_assert.h"
#include "ppc-tdep.h"
/* Pass the arguments in either registers, or in the stack. Using the
return (TYPE_LENGTH (value_type) > 8);
}
+/* Pass the arguments in either registers, or in the stack. Using the
+ ppc 64 bit SysV ABI.
+
+ This implements a dumbed down version of the ABI. It always writes
+ values to memory, GPR and FPR, even when not necessary. Doing this
+ greatly simplifies the logic. */
+
+CORE_ADDR
+ppc64_sysv_abi_push_dummy_call (struct gdbarch *gdbarch, CORE_ADDR func_addr,
+ struct regcache *regcache, CORE_ADDR bp_addr,
+ int nargs, struct value **args, CORE_ADDR sp,
+ int struct_return, CORE_ADDR struct_addr)
+{
+ struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
+ /* By this stage in the proceedings, SP has been decremented by "red
+ zone size" + "struct return size". Fetch the stack-pointer from
+ before this and use that as the BACK_CHAIN. */
+ const CORE_ADDR back_chain = read_sp ();
+ /* See for-loop comment below. */
+ int write_pass;
+ /* Size of the Altivec's vector parameter region, the final value is
+ computed in the for-loop below. */
+ LONGEST vparam_size = 0;
+ /* Size of the general parameter region, the final value is computed
+ in the for-loop below. */
+ LONGEST gparam_size = 0;
+ /* Kevin writes ... I don't mind seeing tdep->wordsize used in the
+ calls to align_up(), align_down(), etc. because this makes it
+ easier to reuse this code (in a copy/paste sense) in the future,
+ but it is a 64-bit ABI and asserting that the wordsize is 8 bytes
+ at some point makes it easier to verify that this function is
+ correct without having to do a non-local analysis to figure out
+ the possible values of tdep->wordsize. */
+ gdb_assert (tdep->wordsize == 8);
+
+ /* Go through the argument list twice.
+
+ Pass 1: Compute the function call's stack space and register
+ requirements.
+
+ Pass 2: Replay the same computation but this time also write the
+ values out to the target. */
+
+ for (write_pass = 0; write_pass < 2; write_pass++)
+ {
+ int argno;
+ /* Next available floating point register for float and double
+ arguments. */
+ int freg = 1;
+ /* Next available general register for non-vector (but possibly
+ float) arguments. */
+ int greg = 3;
+ /* Next available vector register for vector arguments. */
+ int vreg = 2;
+ /* The address, at which the next general purpose parameter
+ (integer, struct, float, ...) should be saved. */
+ CORE_ADDR gparam;
+ /* Address, at which the next Altivec vector parameter should be
+ saved. */
+ CORE_ADDR vparam;
+
+ if (!write_pass)
+ {
+ /* During the first pass, GPARAM and VPARAM are more like
+ offsets (start address zero) than addresses. That way
+ the accumulate the total stack space each region
+ requires. */
+ gparam = 0;
+ vparam = 0;
+ }
+ else
+ {
+ /* Decrement the stack pointer making space for the Altivec
+ and general on-stack parameters. Set vparam and gparam
+ to their corresponding regions. */
+ vparam = align_down (sp - vparam_size, 16);
+ gparam = align_down (vparam - gparam_size, 16);
+ /* Add in space for the TOC, link editor double word,
+ compiler double word, LR save area, CR save area. */
+ sp = align_down (gparam - 48, 16);
+ }
+
+ /* If the function is returning a `struct', then there is an
+ extra hidden parameter (which will be passed in r3)
+ containing the address of that struct.. In that case we
+ should advance one word and start from r4 register to copy
+ parameters. This also consumes one on-stack parameter slot. */
+ if (struct_return)
+ {
+ if (write_pass)
+ regcache_cooked_write_signed (regcache,
+ tdep->ppc_gp0_regnum + greg,
+ struct_addr);
+ greg++;
+ gparam = align_up (gparam + tdep->wordsize, tdep->wordsize);
+ }
+
+ for (argno = 0; argno < nargs; argno++)
+ {
+ struct value *arg = args[argno];
+ struct type *type = check_typedef (VALUE_TYPE (arg));
+ char *val = VALUE_CONTENTS (arg);
+ if (TYPE_CODE (type) == TYPE_CODE_FLT && TYPE_LENGTH (type) <= 8)
+ {
+ /* Floats and Doubles go in f1 .. f13. They also
+ consume a left aligned GREG,, and can end up in
+ memory. */
+ if (write_pass)
+ {
+ if (ppc_floating_point_unit_p (current_gdbarch)
+ && freg <= 13)
+ {
+ char regval[MAX_REGISTER_SIZE];
+ struct type *regtype = register_type (gdbarch,
+ FP0_REGNUM);
+ convert_typed_floating (val, type, regval, regtype);
+ regcache_cooked_write (regcache, FP0_REGNUM + freg,
+ regval);
+ }
+ if (greg <= 10)
+ {
+ /* The ABI states "Single precision floating
+ point values are mapped to the first word in
+ a single doubleword" and "... floating point
+ values mapped to the first eight doublewords
+ of the parameter save area are also passed in
+ general registers").
+
+ This code interprets that to mean: store it,
+ left aligned, in the general register. */
+ char regval[MAX_REGISTER_SIZE];
+ memset (regval, 0, sizeof regval);
+ memcpy (regval, val, TYPE_LENGTH (type));
+ regcache_cooked_write (regcache,
+ tdep->ppc_gp0_regnum + greg,
+ regval);
+ }
+ write_memory (gparam, val, TYPE_LENGTH (type));
+ }
+ /* Always consume parameter stack space. */
+ freg++;
+ greg++;
+ gparam = align_up (gparam + TYPE_LENGTH (type), tdep->wordsize);
+ }
+ else if (TYPE_LENGTH (type) == 16 && TYPE_VECTOR (type)
+ && TYPE_CODE (type) == TYPE_CODE_ARRAY
+ && tdep->ppc_vr0_regnum >= 0)
+ {
+ /* In the Altivec ABI, vectors go in the vector
+ registers v2 .. v13, or when that runs out, a vector
+ annex which goes above all the normal parameters.
+ NOTE: cagney/2003-09-21: This is a guess based on the
+ PowerOpen Altivec ABI. */
+ if (vreg <= 13)
+ {
+ if (write_pass)
+ regcache_cooked_write (regcache,
+ tdep->ppc_vr0_regnum + vreg, val);
+ vreg++;
+ }
+ else
+ {
+ if (write_pass)
+ write_memory (vparam, val, TYPE_LENGTH (type));
+ vparam = align_up (vparam + TYPE_LENGTH (type), 16);
+ }
+ }
+ else if ((TYPE_CODE (type) == TYPE_CODE_INT
+ || TYPE_CODE (type) == TYPE_CODE_ENUM)
+ && TYPE_LENGTH (type) <= 8)
+ {
+ /* Scalars get sign[un]extended and go in gpr3 .. gpr10.
+ They can also end up in memory. */
+ if (write_pass)
+ {
+ /* Sign extend the value, then store it unsigned. */
+ ULONGEST word = unpack_long (type, val);
+ if (greg <= 10)
+ regcache_cooked_write_unsigned (regcache,
+ tdep->ppc_gp0_regnum +
+ greg, word);
+ write_memory_unsigned_integer (gparam, tdep->wordsize,
+ word);
+ }
+ greg++;
+ gparam = align_up (gparam + TYPE_LENGTH (type), tdep->wordsize);
+ }
+ else
+ {
+ int byte;
+ for (byte = 0; byte < TYPE_LENGTH (type);
+ byte += tdep->wordsize)
+ {
+ if (write_pass && greg <= 10)
+ {
+ char regval[MAX_REGISTER_SIZE];
+ int len = TYPE_LENGTH (type) - byte;
+ if (len > tdep->wordsize)
+ len = tdep->wordsize;
+ memset (regval, 0, sizeof regval);
+ /* WARNING: cagney/2003-09-21: As best I can
+ tell, the ABI specifies that the value should
+ be left aligned. Unfortunately, GCC doesn't
+ do this - it instead right aligns even sized
+ values and puts odd sized values on the
+ stack. Work around that by putting both a
+ left and right aligned value into the
+ register (hopefully no one notices :-^).
+ Arrrgh! */
+ /* Left aligned (8 byte values such as pointers
+ fill the buffer). */
+ memcpy (regval, val + byte, len);
+ /* Right aligned (but only if even). */
+ if (len == 1 || len == 2 || len == 4)
+ memcpy (regval + tdep->wordsize - len,
+ val + byte, len);
+ regcache_cooked_write (regcache, greg, regval);
+ }
+ greg++;
+ }
+ if (write_pass)
+ /* WARNING: cagney/2003-09-21: Strictly speaking, this
+ isn't necessary, unfortunately, GCC appears to get
+ "struct convention" parameter passing wrong putting
+ odd sized structures in memory instead of in a
+ register. Work around this by always writing the
+ value to memory. Fortunately, doing this
+ simplifies the code. */
+ write_memory (gparam, val, TYPE_LENGTH (type));
+ /* Always consume parameter stack space. */
+ gparam = align_up (gparam + TYPE_LENGTH (type), tdep->wordsize);
+ }
+ }
+
+ if (!write_pass)
+ {
+ /* Save the true region sizes ready for the second pass. */
+ vparam_size = vparam;
+ /* Make certain that the general parameter save area is at
+ least the minimum 8 registers (or doublewords) in size. */
+ if (greg < 8)
+ gparam_size = 8 * tdep->wordsize;
+ else
+ gparam_size = gparam;
+ }
+ }
+
+ /* Update %sp. */
+ regcache_cooked_write_signed (regcache, SP_REGNUM, sp);
+
+ /* Write the backchain (it occupies WORDSIZED bytes). */
+ write_memory_signed_integer (sp, tdep->wordsize, back_chain);
+
+ /* Point the inferior function call's return address at the dummy's
+ breakpoint. */
+ regcache_cooked_write_signed (regcache, tdep->ppc_lr_regnum, bp_addr);
+
+ /* Find a value for the TOC register. Every symbol should have both
+ ".FN" and "FN" in the minimal symbol table. "FN" points at the
+ FN's descriptor, while ".FN" points at the entry point (which
+ matches FUNC_ADDR). Need to reverse from FUNC_ADDR back to the
+ FN's descriptor address. */
+ {
+ /* Find the minimal symbol that corresponds to FUNC_ADDR (should
+ have the name ".FN"). */
+ struct minimal_symbol *dot_fn = lookup_minimal_symbol_by_pc (func_addr);
+ if (dot_fn != NULL && SYMBOL_LINKAGE_NAME (dot_fn)[0] == '.')
+ {
+ /* Now find the corresponding "FN" (dropping ".") minimal
+ symbol's address. */
+ struct minimal_symbol *fn =
+ lookup_minimal_symbol (SYMBOL_LINKAGE_NAME (dot_fn) + 1, NULL,
+ NULL);
+ if (fn != NULL)
+ {
+ /* Got the address of that descriptor. The TOC is the
+ second double word. */
+ CORE_ADDR toc =
+ read_memory_unsigned_integer (SYMBOL_VALUE_ADDRESS (fn) +
+ tdep->wordsize, tdep->wordsize);
+ regcache_cooked_write_unsigned (regcache,
+ tdep->ppc_gp0_regnum + 2, toc);
+ }
+ }
+ }
+
+ return sp;
+}
+
/* The 64 bit ABI retun value convention.
projects / thirdparty / binutils-gdb.git / commitdiff
