From 773df3e50eb03ab9b114698cd28df4c58f1e3ef0 Mon Sep 17 00:00:00 2001 From: Joel Brobecker Date: Sat, 15 May 2004 05:57:16 +0000 Subject: * rs6000-tdep.c (store_param_on_stack_p): New function, an improved version of some code extracted from skip_prologue(). (skip_prologue): Use store_param_on_stack_p() to detect instructions saving a parameter on the stack. Detect when r0 is used to save a parameter. Do not mark "li rx, SIMM" instructions as part of the prologue, unless the following instruction is also part of the prologue. --- gdb/rs6000-tdep.c | 105 +++++++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 85 insertions(+), 20 deletions(-) (limited to 'gdb/rs6000-tdep.c') diff --git a/gdb/rs6000-tdep.c b/gdb/rs6000-tdep.c index d9807d3..c87f379 100644 --- a/gdb/rs6000-tdep.c +++ b/gdb/rs6000-tdep.c @@ -592,6 +592,76 @@ refine_prologue_limit (CORE_ADDR pc, CORE_ADDR lim_pc) return lim_pc; } +/* Return nonzero if the given instruction OP can be part of the prologue + of a function and saves a parameter on the stack. FRAMEP should be + set if one of the previous instructions in the function has set the + Frame Pointer. */ + +static int +store_param_on_stack_p (unsigned long op, int framep, int *r0_contains_arg) +{ + /* Move parameters from argument registers to temporary register. */ + if ((op & 0xfc0007fe) == 0x7c000378) /* mr(.) Rx,Ry */ + { + /* Rx must be scratch register r0. */ + const int rx_regno = (op >> 16) & 31; + /* Ry: Only r3 - r10 are used for parameter passing. */ + const int ry_regno = GET_SRC_REG (op); + + if (rx_regno == 0 && ry_regno >= 3 && ry_regno <= 10) + { + *r0_contains_arg = 1; + return 1; + } + else + return 0; + } + + /* Save a General Purpose Register on stack. */ + + if ((op & 0xfc1f0003) == 0xf8010000 || /* std Rx,NUM(r1) */ + (op & 0xfc1f0000) == 0xd8010000) /* stfd Rx,NUM(r1) */ + { + /* Rx: Only r3 - r10 are used for parameter passing. */ + const int rx_regno = GET_SRC_REG (op); + + return (rx_regno >= 3 && rx_regno <= 10); + } + + /* Save a General Purpose Register on stack via the Frame Pointer. */ + + if (framep && + ((op & 0xfc1f0000) == 0x901f0000 || /* st rx,NUM(r31) */ + (op & 0xfc1f0000) == 0x981f0000 || /* stb Rx,NUM(r31) */ + (op & 0xfc1f0000) == 0xd81f0000)) /* stfd Rx,NUM(r31) */ + { + /* Rx: Usually, only r3 - r10 are used for parameter passing. + However, the compiler sometimes uses r0 to hold an argument. */ + const int rx_regno = GET_SRC_REG (op); + + return ((rx_regno >= 3 && rx_regno <= 10) + || (rx_regno == 0 && *r0_contains_arg)); + } + + if ((op & 0xfc1f0000) == 0xfc010000) /* frsp, fp?,NUM(r1) */ + { + /* Only f2 - f8 are used for parameter passing. */ + const int src_regno = GET_SRC_REG (op); + + return (src_regno >= 2 && src_regno <= 8); + } + + if (framep && ((op & 0xfc1f0000) == 0xfc1f0000)) /* frsp, fp?,NUM(r31) */ + { + /* Only f2 - f8 are used for parameter passing. */ + const int src_regno = GET_SRC_REG (op); + + return (src_regno >= 2 && src_regno <= 8); + } + + /* Not an insn that saves a parameter on stack. */ + return 0; +} static CORE_ADDR skip_prologue (CORE_ADDR pc, CORE_ADDR lim_pc, struct rs6000_framedata *fdata) @@ -614,6 +684,7 @@ skip_prologue (CORE_ADDR pc, CORE_ADDR lim_pc, struct rs6000_framedata *fdata) int minimal_toc_loaded = 0; int prev_insn_was_prologue_insn = 1; int num_skip_non_prologue_insns = 0; + int r0_contains_arg = 0; const struct bfd_arch_info *arch_info = gdbarch_bfd_arch_info (current_gdbarch); struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch); @@ -682,11 +753,15 @@ skip_prologue (CORE_ADDR pc, CORE_ADDR lim_pc, struct rs6000_framedata *fdata) ones. */ if (lr_reg < 0) lr_reg = (op & 0x03e00000); + if (lr_reg == 0) + r0_contains_arg = 0; continue; } else if ((op & 0xfc1fffff) == 0x7c000026) { /* mfcr Rx */ cr_reg = (op & 0x03e00000); + if (cr_reg == 0) + r0_contains_arg = 0; continue; } @@ -733,6 +808,7 @@ skip_prologue (CORE_ADDR pc, CORE_ADDR lim_pc, struct rs6000_framedata *fdata) for >= 32k frames */ fdata->offset = (op & 0x0000ffff) << 16; fdata->frameless = 0; + r0_contains_arg = 0; continue; } @@ -741,6 +817,7 @@ skip_prologue (CORE_ADDR pc, CORE_ADDR lim_pc, struct rs6000_framedata *fdata) lf of >= 32k frames */ fdata->offset |= (op & 0x0000ffff); fdata->frameless = 0; + r0_contains_arg = 0; continue; } @@ -874,26 +951,7 @@ skip_prologue (CORE_ADDR pc, CORE_ADDR lim_pc, struct rs6000_framedata *fdata) /* store parameters in stack */ } /* Move parameters from argument registers to temporary register. */ - else if ((op & 0xfc0007fe) == 0x7c000378 && /* mr(.) Rx,Ry */ - (((op >> 21) & 31) >= 3) && /* R3 >= Ry >= R10 */ - (((op >> 21) & 31) <= 10) && - (((op >> 16) & 31) == 0)) /* Rx: scratch register r0 */ - { - continue; - } - else if ((op & 0xfc1f0003) == 0xf8010000 || /* std 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(r31) */ - (op & 0xfc1f0000) == 0x981f0000 || /* stb Rx,NUM(r31) */ - (op & 0xfc1f0000) == 0xd81f0000 || /* stfd Rx,NUM(r31) */ - (op & 0xfc1f0000) == 0xfc1f0000)) /* frsp, fp?,NUM(r31) */ + else if (store_param_on_stack_p (op, framep, &r0_contains_arg)) { continue; @@ -962,8 +1020,15 @@ skip_prologue (CORE_ADDR pc, CORE_ADDR lim_pc, struct rs6000_framedata *fdata) else if ((op & 0xffff0000) == 0x38000000 /* li r0, SIMM */ || (op & 0xffff0000) == 0x39c00000) /* li r14, SIMM */ { + if ((op & 0xffff0000) == 0x38000000) + r0_contains_arg = 0; li_found_pc = pc; vr_saved_offset = SIGNED_SHORT (op); + + /* This insn by itself is not part of the prologue, unless + if part of the pair of insns mentioned above. So do not + record this insn as part of the prologue yet. */ + prev_insn_was_prologue_insn = 0; } /* Store vector register S at (r31+r0) aligned to 16 bytes. */ /* 011111 sssss 11111 00000 00111001110 */ -- cgit v1.1