/* Target-dependent code for GDB, the GNU debugger. Copyright 1986, 1987, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997 Free Software Foundation, Inc. This file is part of GDB. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include "defs.h" #include "tm.h" #include "frame.h" #include "inferior.h" #include "symtab.h" #include "target.h" #include "gdbcore.h" #include "symfile.h" #include "objfiles.h" #include "xcoffsolib.h" extern struct obstack frame_cache_obstack; extern int errno; /* Nonzero if we just simulated a single step break. */ int one_stepped; /* Breakpoint shadows for the single step instructions will be kept here. */ static struct sstep_breaks { /* Address, or 0 if this is not in use. */ CORE_ADDR address; /* Shadow contents. */ char data[4]; } stepBreaks[2]; /* Hook for determining the TOC address when calling functions in the inferior under AIX. The initialization code in rs6000-nat.c sets this hook to point to find_toc_address. */ CORE_ADDR (*find_toc_address_hook) PARAMS ((CORE_ADDR)) = NULL; /* Static function prototypes */ static CORE_ADDR branch_dest PARAMS ((int opcode, int instr, CORE_ADDR pc, CORE_ADDR safety)); static void frame_get_cache_fsr PARAMS ((struct frame_info *fi, struct rs6000_framedata *fdatap)); static void pop_dummy_frame PARAMS ((void)); /* Calculate the destination of a branch/jump. Return -1 if not a branch. */ static CORE_ADDR branch_dest (opcode, instr, pc, safety) int opcode; int instr; CORE_ADDR pc; CORE_ADDR safety; { CORE_ADDR dest; int immediate; int absolute; int ext_op; absolute = (int) ((instr >> 1) & 1); switch (opcode) { case 18 : immediate = ((instr & ~3) << 6) >> 6; /* br unconditional */ if (absolute) dest = immediate; else dest = pc + immediate; break; case 16 : immediate = ((instr & ~3) << 16) >> 16; /* br conditional */ if (absolute) dest = immediate; else dest = pc + immediate; break; case 19 : ext_op = (instr>>1) & 0x3ff; if (ext_op == 16) /* br conditional register */ { dest = read_register (LR_REGNUM) & ~3; /* If we are about to return from a signal handler, dest is something like 0x3c90. The current frame is a signal handler caller frame, upon completion of the sigreturn system call execution will return to the saved PC in the frame. */ if (dest < TEXT_SEGMENT_BASE) { struct frame_info *fi; fi = get_current_frame (); if (fi != NULL) dest = read_memory_integer (fi->frame + SIG_FRAME_PC_OFFSET, 4); } } else if (ext_op == 528) /* br cond to count reg */ { dest = read_register (CTR_REGNUM) & ~3; /* If we are about to execute a system call, dest is something like 0x22fc or 0x3b00. Upon completion the system call will return to the address in the link register. */ if (dest < TEXT_SEGMENT_BASE) dest = read_register (LR_REGNUM) & ~3; } else return -1; break; default: return -1; } return (dest < TEXT_SEGMENT_BASE) ? safety : dest; } /* AIX does not support PT_STEP. Simulate it. */ void single_step (signal) enum target_signal signal; { #define INSNLEN(OPCODE) 4 static char le_breakp[] = LITTLE_BREAKPOINT; static char be_breakp[] = BIG_BREAKPOINT; char *breakp = TARGET_BYTE_ORDER == BIG_ENDIAN ? be_breakp : le_breakp; int ii, insn; CORE_ADDR loc; CORE_ADDR breaks[2]; int opcode; if (!one_stepped) { loc = read_pc (); insn = read_memory_integer (loc, 4); breaks[0] = loc + INSNLEN(insn); opcode = insn >> 26; breaks[1] = branch_dest (opcode, insn, loc, breaks[0]); /* Don't put two breakpoints on the same address. */ if (breaks[1] == breaks[0]) breaks[1] = -1; stepBreaks[1].address = 0; for (ii=0; ii < 2; ++ii) { /* ignore invalid breakpoint. */ if ( breaks[ii] == -1) continue; read_memory (breaks[ii], stepBreaks[ii].data, 4); write_memory (breaks[ii], breakp, 4); stepBreaks[ii].address = breaks[ii]; } one_stepped = 1; } else { /* remove step breakpoints. */ for (ii=0; ii < 2; ++ii) if (stepBreaks[ii].address != 0) write_memory (stepBreaks[ii].address, stepBreaks[ii].data, 4); one_stepped = 0; } errno = 0; /* FIXME, don't ignore errors! */ /* What errors? {read,write}_memory call error(). */ } /* return pc value after skipping a function prologue and also return information about a function frame. in struct rs6000_frameinfo fdata: - frameless is TRUE, if function does not have a frame. - nosavedpc is TRUE, if function does not save %pc value in its frame. - offset is the number of bytes used in the frame to save registers. - saved_gpr is the number of the first saved gpr. - saved_fpr is the number of the first saved fpr. - alloca_reg is the number of the register used for alloca() handling. Otherwise -1. - gpr_offset is the offset of the saved gprs - fpr_offset is the offset of the saved fprs - lr_offset is the offset of the saved lr - cr_offset is the offset of the saved cr */ #define SIGNED_SHORT(x) \ ((sizeof (short) == 2) \ ? ((int)(short)(x)) \ : ((int)((((x) & 0xffff) ^ 0x8000) - 0x8000))) #define GET_SRC_REG(x) (((x) >> 21) & 0x1f) CORE_ADDR skip_prologue (pc, fdata) CORE_ADDR pc; struct rs6000_framedata *fdata; { CORE_ADDR orig_pc = pc; char buf[4]; unsigned long op; long offset = 0; int lr_reg = 0; int cr_reg = 0; int reg; int framep = 0; int minimal_toc_loaded = 0; static struct rs6000_framedata zero_frame; *fdata = zero_frame; fdata->saved_gpr = -1; fdata->saved_fpr = -1; fdata->alloca_reg = -1; fdata->frameless = 1; fdata->nosavedpc = 1; if (target_read_memory (pc, buf, 4)) return pc; /* Can't access it -- assume no prologue. */ /* Assume that subsequent fetches can fail with low probability. */ pc -= 4; for (;;) { pc += 4; op = read_memory_integer (pc, 4); if ((op & 0xfc1fffff) == 0x7c0802a6) { /* mflr Rx */ lr_reg = (op & 0x03e00000) | 0x90010000; continue; } else if ((op & 0xfc1fffff) == 0x7c000026) { /* mfcr Rx */ cr_reg = (op & 0x03e00000) | 0x90010000; continue; } else if ((op & 0xfc1f0000) == 0xd8010000) { /* stfd Rx,NUM(r1) */ reg = GET_SRC_REG (op); if (fdata->saved_fpr == -1 || fdata->saved_fpr > reg) { fdata->saved_fpr = reg; fdata->fpr_offset = SIGNED_SHORT (op) + offset; } continue; } else if (((op & 0xfc1f0000) == 0xbc010000) || /* stm Rx, NUM(r1) */ ((op & 0xfc1f0000) == 0x90010000 && /* st rx,NUM(r1), rx >= r13 */ (op & 0x03e00000) >= 0x01a00000)) { reg = GET_SRC_REG (op); if (fdata->saved_gpr == -1 || fdata->saved_gpr > reg) { fdata->saved_gpr = reg; fdata->gpr_offset = SIGNED_SHORT (op) + offset; } continue; } else if ((op & 0xffff0000) == 0x3c000000) { /* addis 0,0,NUM, used for >= 32k frames */ fdata->offset = (op & 0x0000ffff) << 16; fdata->frameless = 0; continue; } else if ((op & 0xffff0000) == 0x60000000) { /* ori 0,0,NUM, 2nd ha lf of >= 32k frames */ fdata->offset |= (op & 0x0000ffff); fdata->frameless = 0; continue; } else if ((op & 0xffff0000) == lr_reg) { /* st Rx,NUM(r1) where Rx == lr */ fdata->lr_offset = SIGNED_SHORT (op) + offset; fdata->nosavedpc = 0; lr_reg = 0; continue; } else if ((op & 0xffff0000) == cr_reg) { /* st Rx,NUM(r1) where Rx == cr */ fdata->cr_offset = SIGNED_SHORT (op) + offset; cr_reg = 0; continue; } else if (op == 0x48000005) { /* bl .+4 used in -mrelocatable */ continue; } else if (op == 0x48000004) { /* b .+4 (xlc) */ break; } else if (((op & 0xffff0000) == 0x801e0000 || /* lwz 0,NUM(r30), used in V.4 -mrelocatable */ op == 0x7fc0f214) && /* add r30,r0,r30, used in V.4 -mrelocatable */ lr_reg == 0x901e0000) { continue; } else if ((op & 0xffff0000) == 0x3fc00000 || /* addis 30,0,foo@ha, used in V.4 -mminimal-toc */ (op & 0xffff0000) == 0x3bde0000) { /* addi 30,30,foo@l */ continue; } else if ((op & 0xfc000000) == 0x48000000) { /* bl foo, to save fprs??? */ fdata->frameless = 0; /* Don't skip over the subroutine call if it is not within the first three instructions of the prologue. */ if ((pc - orig_pc) > 8) break; op = read_memory_integer (pc+4, 4); /* At this point, make sure this is not a trampoline function (a function that simply calls another functions, and nothing else). If the next is not a nop, this branch was part of the function prologue. */ if (op == 0x4def7b82 || op == 0) /* crorc 15, 15, 15 */ break; /* don't skip over this branch */ continue; /* update stack pointer */ } else if ((op & 0xffff0000) == 0x94210000) { /* stu r1,NUM(r1) */ fdata->frameless = 0; fdata->offset = SIGNED_SHORT (op); offset = fdata->offset; continue; } else if (op == 0x7c21016e) { /* stwux 1,1,0 */ fdata->frameless = 0; offset = fdata->offset; continue; /* Load up minimal toc pointer */ } else if ((op >> 22) == 0x20f && ! minimal_toc_loaded) { /* l r31,... or l r30,... */ minimal_toc_loaded = 1; continue; /* store parameters in stack */ } else if ((op & 0xfc1f0000) == 0x90010000 || /* st rx,NUM(r1) */ (op & 0xfc1f0000) == 0xd8010000 || /* stfd Rx,NUM(r1) */ (op & 0xfc1f0000) == 0xfc010000) { /* frsp, fp?,NUM(r1) */ continue; /* store parameters in stack via frame pointer */ } else if (framep && ((op & 0xfc1f0000) == 0x901f0000 || /* st rx,NUM(r1) */ (op & 0xfc1f0000) == 0xd81f0000 || /* stfd Rx,NUM(r1) */ (op & 0xfc1f0000) == 0xfc1f0000)) { /* frsp, fp?,NUM(r1) */ continue; /* Set up frame pointer */ } else if (op == 0x603f0000 /* oril r31, r1, 0x0 */ || op == 0x7c3f0b78) { /* mr r31, r1 */ fdata->frameless = 0; framep = 1; fdata->alloca_reg = 31; continue; /* Another way to set up the frame pointer. */ } else if ((op & 0xfc1fffff) == 0x38010000) { /* addi rX, r1, 0x0 */ fdata->frameless = 0; framep = 1; fdata->alloca_reg = (op & ~0x38010000) >> 21; continue; } else { break; } } #if 0 /* I have problems with skipping over __main() that I need to address * sometime. Previously, I used to use misc_function_vector which * didn't work as well as I wanted to be. -MGO */ /* If the first thing after skipping a prolog is a branch to a function, this might be a call to an initializer in main(), introduced by gcc2. We'd like to skip over it as well. Fortunately, xlc does some extra work before calling a function right after a prologue, thus we can single out such gcc2 behaviour. */ if ((op & 0xfc000001) == 0x48000001) { /* bl foo, an initializer function? */ op = read_memory_integer (pc+4, 4); if (op == 0x4def7b82) { /* cror 0xf, 0xf, 0xf (nop) */ /* check and see if we are in main. If so, skip over this initializer function as well. */ tmp = find_pc_misc_function (pc); if (tmp >= 0 && STREQ (misc_function_vector [tmp].name, "main")) return pc + 8; } } #endif /* 0 */ fdata->offset = - fdata->offset; return pc; } /************************************************************************* Support for creating pushind a dummy frame into the stack, and popping frames, etc. *************************************************************************/ /* The total size of dummy frame is 436, which is; 32 gpr's - 128 bytes 32 fpr's - 256 " 7 the rest - 28 " and 24 extra bytes for the callee's link area. The last 24 bytes for the link area might not be necessary, since it will be taken care of by push_arguments(). */ #define DUMMY_FRAME_SIZE 436 #define DUMMY_FRAME_ADDR_SIZE 10 /* Make sure you initialize these in somewhere, in case gdb gives up what it was debugging and starts debugging something else. FIXMEibm */ static int dummy_frame_count = 0; static int dummy_frame_size = 0; static CORE_ADDR *dummy_frame_addr = 0; extern int stop_stack_dummy; /* push a dummy frame into stack, save all register. Currently we are saving only gpr's and fpr's, which is not good enough! FIXMEmgo */ void push_dummy_frame () { /* stack pointer. */ CORE_ADDR sp; /* Same thing, target byte order. */ char sp_targ[4]; /* link register. */ CORE_ADDR pc; /* Same thing, target byte order. */ char pc_targ[4]; /* Needed to figure out where to save the dummy link area. FIXME: There should be an easier way to do this, no? tiemann 9/9/95. */ struct rs6000_framedata fdata; int ii; target_fetch_registers (-1); if (dummy_frame_count >= dummy_frame_size) { dummy_frame_size += DUMMY_FRAME_ADDR_SIZE; if (dummy_frame_addr) dummy_frame_addr = (CORE_ADDR*) xrealloc (dummy_frame_addr, sizeof(CORE_ADDR) * (dummy_frame_size)); else dummy_frame_addr = (CORE_ADDR*) xmalloc (sizeof(CORE_ADDR) * (dummy_frame_size)); } sp = read_register(SP_REGNUM); pc = read_register(PC_REGNUM); store_address (pc_targ, 4, pc); skip_prologue (get_pc_function_start (pc) + FUNCTION_START_OFFSET, &fdata); dummy_frame_addr [dummy_frame_count++] = sp; /* Be careful! If the stack pointer is not decremented first, then kernel thinks he is free to use the space underneath it. And kernel actually uses that area for IPC purposes when executing ptrace(2) calls. So before writing register values into the new frame, decrement and update %sp first in order to secure your frame. */ /* FIXME: We don't check if the stack really has this much space. This is a problem on the ppc simulator (which only grants one page (4096 bytes) by default. */ write_register (SP_REGNUM, sp-DUMMY_FRAME_SIZE); /* gdb relies on the state of current_frame. We'd better update it, otherwise things like do_registers_info() wouldn't work properly! */ flush_cached_frames (); /* save program counter in link register's space. */ write_memory (sp + (fdata.lr_offset ? fdata.lr_offset : DEFAULT_LR_SAVE), pc_targ, 4); /* save all floating point and general purpose registers here. */ /* fpr's, f0..f31 */ for (ii = 0; ii < 32; ++ii) write_memory (sp-8-(ii*8), ®isters[REGISTER_BYTE (31-ii+FP0_REGNUM)], 8); /* gpr's r0..r31 */ for (ii=1; ii <=32; ++ii) write_memory (sp-256-(ii*4), ®isters[REGISTER_BYTE (32-ii)], 4); /* so far, 32*2 + 32 words = 384 bytes have been written. 7 extra registers in our register set: pc, ps, cnd, lr, cnt, xer, mq */ for (ii=1; ii <= (LAST_SP_REGNUM-FIRST_SP_REGNUM+1); ++ii) { write_memory (sp-384-(ii*4), ®isters[REGISTER_BYTE (FPLAST_REGNUM + ii)], 4); } /* Save sp or so called back chain right here. */ store_address (sp_targ, 4, sp); write_memory (sp-DUMMY_FRAME_SIZE, sp_targ, 4); sp -= DUMMY_FRAME_SIZE; /* And finally, this is the back chain. */ write_memory (sp+8, pc_targ, 4); } /* Pop a dummy frame. In rs6000 when we push a dummy frame, we save all of the registers. This is usually done before user calls a function explicitly. After a dummy frame is pushed, some instructions are copied into stack, and stack pointer is decremented even more. Since we don't have a frame pointer to get back to the parent frame of the dummy, we start having trouble poping it. Therefore, we keep a dummy frame stack, keeping addresses of dummy frames as such. When poping happens and when we detect that was a dummy frame, we pop it back to its parent by using dummy frame stack (`dummy_frame_addr' array). FIXME: This whole concept is broken. You should be able to detect a dummy stack frame *on the user's stack itself*. When you do, then you know the format of that stack frame -- including its saved SP register! There should *not* be a separate stack in the GDB process that keeps track of these dummy frames! -- gnu@cygnus.com Aug92 */ static void pop_dummy_frame () { CORE_ADDR sp, pc; int ii; sp = dummy_frame_addr [--dummy_frame_count]; /* restore all fpr's. */ for (ii = 1; ii <= 32; ++ii) read_memory (sp-(ii*8), ®isters[REGISTER_BYTE (32-ii+FP0_REGNUM)], 8); /* restore all gpr's */ for (ii=1; ii <= 32; ++ii) { read_memory (sp-256-(ii*4), ®isters[REGISTER_BYTE (32-ii)], 4); } /* restore the rest of the registers. */ for (ii=1; ii <=(LAST_SP_REGNUM-FIRST_SP_REGNUM+1); ++ii) read_memory (sp-384-(ii*4), ®isters[REGISTER_BYTE (FPLAST_REGNUM + ii)], 4); read_memory (sp-(DUMMY_FRAME_SIZE-8), ®isters [REGISTER_BYTE(PC_REGNUM)], 4); /* when a dummy frame was being pushed, we had to decrement %sp first, in order to secure astack space. Thus, saved %sp (or %r1) value, is not the one we should restore. Change it with the one we need. */ memcpy (®isters [REGISTER_BYTE(FP_REGNUM)], (char *) &sp, sizeof (int)); /* Now we can restore all registers. */ target_store_registers (-1); pc = read_pc (); flush_cached_frames (); } /* pop the innermost frame, go back to the caller. */ void pop_frame () { CORE_ADDR pc, lr, sp, prev_sp; /* %pc, %lr, %sp */ struct rs6000_framedata fdata; struct frame_info *frame = get_current_frame (); int addr, ii; pc = read_pc (); sp = FRAME_FP (frame); if (stop_stack_dummy) { #ifdef USE_GENERIC_DUMMY_FRAMES generic_pop_dummy_frame (); flush_cached_frames (); return; #else if (dummy_frame_count) pop_dummy_frame (); return; #endif } /* Make sure that all registers are valid. */ read_register_bytes (0, NULL, REGISTER_BYTES); /* figure out previous %pc value. If the function is frameless, it is still in the link register, otherwise walk the frames and retrieve the saved %pc value in the previous frame. */ addr = get_pc_function_start (frame->pc) + FUNCTION_START_OFFSET; (void) skip_prologue (addr, &fdata); if (fdata.frameless) prev_sp = sp; else prev_sp = read_memory_integer (sp, 4); if (fdata.lr_offset == 0) lr = read_register (LR_REGNUM); else lr = read_memory_integer (prev_sp + fdata.lr_offset, 4); /* reset %pc value. */ write_register (PC_REGNUM, lr); /* reset register values if any was saved earlier. */ addr = prev_sp - fdata.offset; if (fdata.saved_gpr != -1) for (ii = fdata.saved_gpr; ii <= 31; ++ii) { read_memory (addr, ®isters [REGISTER_BYTE (ii)], 4); addr += 4; } if (fdata.saved_fpr != -1) for (ii = fdata.saved_fpr; ii <= 31; ++ii) { read_memory (addr, ®isters [REGISTER_BYTE (ii+FP0_REGNUM)], 8); addr += 8; } write_register (SP_REGNUM, prev_sp); target_store_registers (-1); flush_cached_frames (); } /* fixup the call sequence of a dummy function, with the real function address. its argumets will be passed by gdb. */ void rs6000_fix_call_dummy (dummyname, pc, fun, nargs, args, type, gcc_p) char *dummyname; CORE_ADDR pc; CORE_ADDR fun; int nargs; value_ptr *args; struct type *type; int gcc_p; { #define TOC_ADDR_OFFSET 20 #define TARGET_ADDR_OFFSET 28 int ii; CORE_ADDR target_addr; if (find_toc_address_hook != NULL) { CORE_ADDR tocvalue; tocvalue = (*find_toc_address_hook) (fun); ii = *(int*)((char*)dummyname + TOC_ADDR_OFFSET); ii = (ii & 0xffff0000) | (tocvalue >> 16); *(int*)((char*)dummyname + TOC_ADDR_OFFSET) = ii; ii = *(int*)((char*)dummyname + TOC_ADDR_OFFSET+4); ii = (ii & 0xffff0000) | (tocvalue & 0x0000ffff); *(int*)((char*)dummyname + TOC_ADDR_OFFSET+4) = ii; } target_addr = fun; ii = *(int*)((char*)dummyname + TARGET_ADDR_OFFSET); ii = (ii & 0xffff0000) | (target_addr >> 16); *(int*)((char*)dummyname + TARGET_ADDR_OFFSET) = ii; ii = *(int*)((char*)dummyname + TARGET_ADDR_OFFSET+4); ii = (ii & 0xffff0000) | (target_addr & 0x0000ffff); *(int*)((char*)dummyname + TARGET_ADDR_OFFSET+4) = ii; } /* Pass the arguments in either registers, or in the stack. In RS6000, the first eight words of the argument list (that might be less than eight parameters if some parameters occupy more than one word) are passed in r3..r11 registers. float and double parameters are passed in fpr's, in addition to that. Rest of the parameters if any are passed in user stack. There might be cases in which half of the parameter is copied into registers, the other half is pushed into stack. If the function is returning a structure, then the return address is passed in r3, then the first 7 words of the parameters can be passed in registers, starting from r4. */ CORE_ADDR push_arguments (nargs, args, sp, struct_return, struct_addr) int nargs; value_ptr *args; CORE_ADDR sp; int struct_return; CORE_ADDR struct_addr; { int ii; int len = 0; int argno; /* current argument number */ int argbytes; /* current argument byte */ char tmp_buffer [50]; int f_argno = 0; /* current floating point argno */ value_ptr arg = 0; struct type *type; CORE_ADDR saved_sp; #ifndef USE_GENERIC_DUMMY_FRAMES if ( dummy_frame_count <= 0) printf_unfiltered ("FATAL ERROR -push_arguments()! frame not found!!\n"); #endif /* GENERIC_DUMMY_FRAMES */ /* The first eight words of ther arguments are passed in registers. Copy them appropriately. If the function is returning a `struct', then the first word (which will be passed in r3) is used for struct return address. In that case we should advance one word and start from r4 register to copy parameters. */ ii = struct_return ? 1 : 0; /* effectively indirect call... gcc does... return_val example( float, int); eabi: float in fp0, int in r3 offset of stack on overflow 8/16 for varargs, must go by type. power open: float in r3&r4, int in r5 offset of stack on overflow different both: return in r3 or f0. If no float, must study how gcc emulates floats; pay attention to arg promotion. User may have to cast\args to handle promotion correctly since gdb won't know if prototype supplied or not. */ for (argno=0, argbytes=0; argno < nargs && ii<8; ++ii) { arg = args[argno]; type = check_typedef (VALUE_TYPE (arg)); len = TYPE_LENGTH (type); if (TYPE_CODE (type) == TYPE_CODE_FLT) { /* floating point arguments are passed in fpr's, as well as gpr's. There are 13 fpr's reserved for passing parameters. At this point there is no way we would run out of them. */ if (len > 8) printf_unfiltered ( "Fatal Error: a floating point parameter #%d with a size > 8 is found!\n", argno); memcpy (®isters[REGISTER_BYTE(FP0_REGNUM + 1 + f_argno)], VALUE_CONTENTS (arg), len); ++f_argno; } if (len > 4) { /* Argument takes more than one register. */ while (argbytes < len) { memset (®isters[REGISTER_BYTE(ii+3)], 0, sizeof(int)); memcpy (®isters[REGISTER_BYTE(ii+3)], ((char*)VALUE_CONTENTS (arg))+argbytes, (len - argbytes) > 4 ? 4 : len - argbytes); ++ii, argbytes += 4; if (ii >= 8) goto ran_out_of_registers_for_arguments; } argbytes = 0; --ii; } else { /* Argument can fit in one register. No problem. */ memset (®isters[REGISTER_BYTE(ii+3)], 0, sizeof(int)); memcpy (®isters[REGISTER_BYTE(ii+3)], VALUE_CONTENTS (arg), len); } ++argno; } ran_out_of_registers_for_arguments: #ifdef USE_GENERIC_DUMMY_FRAMES saved_sp = read_sp (); #else /* location for 8 parameters are always reserved. */ sp -= 4 * 8; /* another six words for back chain, TOC register, link register, etc. */ sp -= 24; #endif /* GENERIC_DUMMY_FRAMES */ /* if there are more arguments, allocate space for them in the stack, then push them starting from the ninth one. */ if ((argno < nargs) || argbytes) { int space = 0, jj; if (argbytes) { space += ((len - argbytes + 3) & -4); jj = argno + 1; } else jj = argno; for (; jj < nargs; ++jj) { value_ptr val = args[jj]; space += ((TYPE_LENGTH (VALUE_TYPE (val))) + 3) & -4; } /* add location required for the rest of the parameters */ space = (space + 7) & -8; sp -= space; /* This is another instance we need to be concerned about securing our stack space. If we write anything underneath %sp (r1), we might conflict with the kernel who thinks he is free to use this area. So, update %sp first before doing anything else. */ write_register (SP_REGNUM, sp); /* if the last argument copied into the registers didn't fit there completely, push the rest of it into stack. */ if (argbytes) { write_memory (sp+24+(ii*4), ((char*)VALUE_CONTENTS (arg))+argbytes, len - argbytes); ++argno; ii += ((len - argbytes + 3) & -4) / 4; } /* push the rest of the arguments into stack. */ for (; argno < nargs; ++argno) { arg = args[argno]; type = check_typedef (VALUE_TYPE (arg)); len = TYPE_LENGTH (type); /* float types should be passed in fpr's, as well as in the stack. */ if (TYPE_CODE (type) == TYPE_CODE_FLT && f_argno < 13) { if (len > 8) printf_unfiltered ( "Fatal Error: a floating point parameter #%d with a size > 8 is found!\n", argno); memcpy (®isters[REGISTER_BYTE(FP0_REGNUM + 1 + f_argno)], VALUE_CONTENTS (arg), len); ++f_argno; } write_memory (sp+24+(ii*4), (char *) VALUE_CONTENTS (arg), len); ii += ((len + 3) & -4) / 4; } } else /* Secure stack areas first, before doing anything else. */ write_register (SP_REGNUM, sp); #ifndef USE_GENERIC_DUMMY_FRAMES /* we want to copy 24 bytes of target's frame to dummy's frame, then set back chain to point to new frame. */ saved_sp = dummy_frame_addr [dummy_frame_count - 1]; read_memory (saved_sp, tmp_buffer, 24); write_memory (sp, tmp_buffer, 24); #endif /* GENERIC_DUMMY_FRAMES */ /* set back chain properly */ store_address (tmp_buffer, 4, saved_sp); write_memory (sp, tmp_buffer, 4); target_store_registers (-1); return sp; } #ifdef ELF_OBJECT_FORMAT /* Function: ppc_push_return_address (pc, sp) Set up the return address for the inferior function call. */ CORE_ADDR ppc_push_return_address (pc, sp) CORE_ADDR pc; CORE_ADDR sp; { write_register (LR_REGNUM, CALL_DUMMY_ADDRESS ()); return sp; } #endif /* a given return value in `regbuf' with a type `valtype', extract and copy its value into `valbuf' */ void extract_return_value (valtype, regbuf, valbuf) struct type *valtype; char regbuf[REGISTER_BYTES]; char *valbuf; { int offset = 0; if (TYPE_CODE (valtype) == TYPE_CODE_FLT) { double dd; float ff; /* floats and doubles are returned in fpr1. fpr's have a size of 8 bytes. We need to truncate the return value into float size (4 byte) if necessary. */ if (TYPE_LENGTH (valtype) > 4) /* this is a double */ memcpy (valbuf, ®buf[REGISTER_BYTE (FP0_REGNUM + 1)], TYPE_LENGTH (valtype)); else { /* float */ memcpy (&dd, ®buf[REGISTER_BYTE (FP0_REGNUM + 1)], 8); ff = (float)dd; memcpy (valbuf, &ff, sizeof(float)); } } else { /* return value is copied starting from r3. */ if (TARGET_BYTE_ORDER == BIG_ENDIAN && TYPE_LENGTH (valtype) < REGISTER_RAW_SIZE (3)) offset = REGISTER_RAW_SIZE (3) - TYPE_LENGTH (valtype); memcpy (valbuf, regbuf + REGISTER_BYTE (3) + offset, TYPE_LENGTH (valtype)); } } /* keep structure return address in this variable. FIXME: This is a horrid kludge which should not be allowed to continue living. This only allows a single nested call to a structure-returning function. Come on, guys! -- gnu@cygnus.com, Aug 92 */ CORE_ADDR rs6000_struct_return_address; /* Indirect function calls use a piece of trampoline code to do context switching, i.e. to set the new TOC table. Skip such code if we are on its first instruction (as when we have single-stepped to here). Also skip shared library trampoline code (which is different from indirect function call trampolines). Result is desired PC to step until, or NULL if we are not in trampoline code. */ CORE_ADDR skip_trampoline_code (pc) CORE_ADDR pc; { register unsigned int ii, op; CORE_ADDR solib_target_pc; static unsigned trampoline_code[] = { 0x800b0000, /* l r0,0x0(r11) */ 0x90410014, /* st r2,0x14(r1) */ 0x7c0903a6, /* mtctr r0 */ 0x804b0004, /* l r2,0x4(r11) */ 0x816b0008, /* l r11,0x8(r11) */ 0x4e800420, /* bctr */ 0x4e800020, /* br */ 0 }; /* If pc is in a shared library trampoline, return its target. */ solib_target_pc = find_solib_trampoline_target (pc); if (solib_target_pc) return solib_target_pc; for (ii=0; trampoline_code[ii]; ++ii) { op = read_memory_integer (pc + (ii*4), 4); if (op != trampoline_code [ii]) return 0; } ii = read_register (11); /* r11 holds destination addr */ pc = read_memory_integer (ii, 4); /* (r11) value */ return pc; } /* Determines whether the function FI has a frame on the stack or not. */ int frameless_function_invocation (fi) struct frame_info *fi; { CORE_ADDR func_start; struct rs6000_framedata fdata; /* Don't even think about framelessness except on the innermost frame or if the function was interrupted by a signal. */ if (fi->next != NULL && !fi->next->signal_handler_caller) return 0; func_start = get_pc_function_start (fi->pc); /* If we failed to find the start of the function, it is a mistake to inspect the instructions. */ if (!func_start) { /* A frame with a zero PC is usually created by dereferencing a NULL function pointer, normally causing an immediate core dump of the inferior. Mark function as frameless, as the inferior has no chance of setting up a stack frame. */ if (fi->pc == 0) return 1; else return 0; } func_start += FUNCTION_START_OFFSET; (void) skip_prologue (func_start, &fdata); return fdata.frameless; } /* Return the PC saved in a frame */ unsigned long frame_saved_pc (fi) struct frame_info *fi; { CORE_ADDR func_start; struct rs6000_framedata fdata; if (fi->signal_handler_caller) return read_memory_integer (fi->frame + SIG_FRAME_PC_OFFSET, 4); #ifdef USE_GENERIC_DUMMY_FRAMES if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame)) return generic_read_register_dummy(fi->pc, fi->frame, PC_REGNUM); #endif /* GENERIC_DUMMY_FRAMES */ func_start = get_pc_function_start (fi->pc) + FUNCTION_START_OFFSET; /* If we failed to find the start of the function, it is a mistake to inspect the instructions. */ if (!func_start) return 0; (void) skip_prologue (func_start, &fdata); if (fdata.lr_offset == 0 && fi->next != NULL) { if (fi->next->signal_handler_caller) return read_memory_integer (fi->next->frame + SIG_FRAME_LR_OFFSET, 4); else return read_memory_integer (rs6000_frame_chain (fi) + DEFAULT_LR_SAVE, 4); } if (fdata.lr_offset == 0) return read_register (LR_REGNUM); return read_memory_integer (rs6000_frame_chain (fi) + fdata.lr_offset, 4); } /* If saved registers of frame FI are not known yet, read and cache them. &FDATAP contains rs6000_framedata; TDATAP can be NULL, in which case the framedata are read. */ static void frame_get_cache_fsr (fi, fdatap) struct frame_info *fi; struct rs6000_framedata *fdatap; { int ii; CORE_ADDR frame_addr; struct rs6000_framedata work_fdata; if (fi->cache_fsr) return; if (fdatap == NULL) { fdatap = &work_fdata; (void) skip_prologue (get_pc_function_start (fi->pc), fdatap); } fi->cache_fsr = (struct frame_saved_regs *) obstack_alloc (&frame_cache_obstack, sizeof (struct frame_saved_regs)); memset (fi->cache_fsr, '\0', sizeof (struct frame_saved_regs)); if (fi->prev && fi->prev->frame) frame_addr = fi->prev->frame; else frame_addr = read_memory_integer (fi->frame, 4); /* if != -1, fdatap->saved_fpr is the smallest number of saved_fpr. All fpr's from saved_fpr to fp31 are saved. */ if (fdatap->saved_fpr >= 0) { int fpr_offset = frame_addr + fdatap->fpr_offset; for (ii = fdatap->saved_fpr; ii < 32; ii++) { fi->cache_fsr->regs [FP0_REGNUM + ii] = fpr_offset; fpr_offset += 8; } } /* if != -1, fdatap->saved_gpr is the smallest number of saved_gpr. All gpr's from saved_gpr to gpr31 are saved. */ if (fdatap->saved_gpr >= 0) { int gpr_offset = frame_addr + fdatap->gpr_offset; for (ii = fdatap->saved_gpr; ii < 32; ii++) { fi->cache_fsr->regs [ii] = gpr_offset; gpr_offset += 4; } } /* If != 0, fdatap->cr_offset is the offset from the frame that holds the CR. */ if (fdatap->cr_offset != 0) fi->cache_fsr->regs [CR_REGNUM] = frame_addr + fdatap->cr_offset; /* If != 0, fdatap->lr_offset is the offset from the frame that holds the LR. */ if (fdatap->lr_offset != 0) fi->cache_fsr->regs [LR_REGNUM] = frame_addr + fdatap->lr_offset; } /* Return the address of a frame. This is the inital %sp value when the frame was first allocated. For functions calling alloca(), it might be saved in an alloca register. */ CORE_ADDR frame_initial_stack_address (fi) struct frame_info *fi; { CORE_ADDR tmpaddr; struct rs6000_framedata fdata; struct frame_info *callee_fi; /* if the initial stack pointer (frame address) of this frame is known, just return it. */ if (fi->initial_sp) return fi->initial_sp; /* find out if this function is using an alloca register.. */ (void) skip_prologue (get_pc_function_start (fi->pc), &fdata); /* if saved registers of this frame are not known yet, read and cache them. */ if (!fi->cache_fsr) frame_get_cache_fsr (fi, &fdata); /* If no alloca register used, then fi->frame is the value of the %sp for this frame, and it is good enough. */ if (fdata.alloca_reg < 0) { fi->initial_sp = fi->frame; return fi->initial_sp; } /* This function has an alloca register. If this is the top-most frame (with the lowest address), the value in alloca register is good. */ if (!fi->next) return fi->initial_sp = read_register (fdata.alloca_reg); /* Otherwise, this is a caller frame. Callee has usually already saved registers, but there are exceptions (such as when the callee has no parameters). Find the address in which caller's alloca register is saved. */ for (callee_fi = fi->next; callee_fi; callee_fi = callee_fi->next) { if (!callee_fi->cache_fsr) frame_get_cache_fsr (callee_fi, NULL); /* this is the address in which alloca register is saved. */ tmpaddr = callee_fi->cache_fsr->regs [fdata.alloca_reg]; if (tmpaddr) { fi->initial_sp = read_memory_integer (tmpaddr, 4); return fi->initial_sp; } /* Go look into deeper levels of the frame chain to see if any one of the callees has saved alloca register. */ } /* If alloca register was not saved, by the callee (or any of its callees) then the value in the register is still good. */ return fi->initial_sp = read_register (fdata.alloca_reg); } CORE_ADDR rs6000_frame_chain (thisframe) struct frame_info *thisframe; { CORE_ADDR fp; #ifdef USE_GENERIC_DUMMY_FRAMES if (PC_IN_CALL_DUMMY (thisframe->pc, thisframe->frame, thisframe->frame)) return thisframe->frame; /* dummy frame same as caller's frame */ #endif /* GENERIC_DUMMY_FRAMES */ if (inside_entry_file (thisframe->pc) || thisframe->pc == entry_point_address ()) return 0; if (thisframe->signal_handler_caller) fp = read_memory_integer (thisframe->frame + SIG_FRAME_FP_OFFSET, 4); else if (thisframe->next != NULL && thisframe->next->signal_handler_caller && frameless_function_invocation (thisframe)) /* A frameless function interrupted by a signal did not change the frame pointer. */ fp = FRAME_FP (thisframe); else fp = read_memory_integer ((thisframe)->frame, 4); #ifdef USE_GENERIC_DUMMY_FRAMES { CORE_ADDR fpp, lr; lr = read_register (LR_REGNUM); if (lr == entry_point_address ()) if (fp != 0 && (fpp = read_memory_integer (fp, 4)) != 0) if (PC_IN_CALL_DUMMY (lr, fpp, fpp)) return fpp; } #endif /* GENERIC_DUMMY_FRAMES */ return fp; } /* Return nonzero if ADDR (a function pointer) is in the data space and is therefore a special function pointer. */ int is_magic_function_pointer (addr) CORE_ADDR addr; { struct obj_section *s; s = find_pc_section (addr); if (s && s->the_bfd_section->flags & SEC_CODE) return 0; else return 1; } #ifdef GDB_TARGET_POWERPC int gdb_print_insn_powerpc (memaddr, info) bfd_vma memaddr; disassemble_info *info; { if (TARGET_BYTE_ORDER == BIG_ENDIAN) return print_insn_big_powerpc (memaddr, info); else return print_insn_little_powerpc (memaddr, info); } #endif /* Function: get_saved_register Just call the generic_get_saved_register function. */ void get_saved_register (raw_buffer, optimized, addrp, frame, regnum, lval) char *raw_buffer; int *optimized; CORE_ADDR *addrp; struct frame_info *frame; int regnum; enum lval_type *lval; { generic_get_saved_register (raw_buffer, optimized, addrp, frame, regnum, lval); } void _initialize_rs6000_tdep () { /* FIXME, this should not be decided via ifdef. */ #ifdef GDB_TARGET_POWERPC tm_print_insn = gdb_print_insn_powerpc; #else tm_print_insn = print_insn_rs6000; #endif }