| /* Definitions for computing resource usage of specific insns. |
| Copyright (C) 1999-2015 Free Software Foundation, Inc. |
| |
| This file is part of GCC. |
| |
| GCC 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 3, or (at your option) any later |
| version. |
| |
| GCC 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 GCC; see the file COPYING3. If not see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include "config.h" |
| #include "system.h" |
| #include "coretypes.h" |
| #include "tm.h" |
| #include "diagnostic-core.h" |
| #include "rtl.h" |
| #include "tm_p.h" |
| #include "hard-reg-set.h" |
| #include "hashtab.h" |
| #include "hash-set.h" |
| #include "vec.h" |
| #include "machmode.h" |
| #include "input.h" |
| #include "function.h" |
| #include "regs.h" |
| #include "flags.h" |
| #include "output.h" |
| #include "dominance.h" |
| #include "cfg.h" |
| #include "predict.h" |
| #include "basic-block.h" |
| #include "resource.h" |
| #include "except.h" |
| #include "insn-attr.h" |
| #include "params.h" |
| #include "df.h" |
| |
| /* This structure is used to record liveness information at the targets or |
| fallthrough insns of branches. We will most likely need the information |
| at targets again, so save them in a hash table rather than recomputing them |
| each time. */ |
| |
| struct target_info |
| { |
| int uid; /* INSN_UID of target. */ |
| struct target_info *next; /* Next info for same hash bucket. */ |
| HARD_REG_SET live_regs; /* Registers live at target. */ |
| int block; /* Basic block number containing target. */ |
| int bb_tick; /* Generation count of basic block info. */ |
| }; |
| |
| #define TARGET_HASH_PRIME 257 |
| |
| /* Indicates what resources are required at the beginning of the epilogue. */ |
| static struct resources start_of_epilogue_needs; |
| |
| /* Indicates what resources are required at function end. */ |
| static struct resources end_of_function_needs; |
| |
| /* Define the hash table itself. */ |
| static struct target_info **target_hash_table = NULL; |
| |
| /* For each basic block, we maintain a generation number of its basic |
| block info, which is updated each time we move an insn from the |
| target of a jump. This is the generation number indexed by block |
| number. */ |
| |
| static int *bb_ticks; |
| |
| /* Marks registers possibly live at the current place being scanned by |
| mark_target_live_regs. Also used by update_live_status. */ |
| |
| static HARD_REG_SET current_live_regs; |
| |
| /* Marks registers for which we have seen a REG_DEAD note but no assignment. |
| Also only used by the next two functions. */ |
| |
| static HARD_REG_SET pending_dead_regs; |
| |
| static void update_live_status (rtx, const_rtx, void *); |
| static int find_basic_block (rtx_insn *, int); |
| static rtx_insn *next_insn_no_annul (rtx_insn *); |
| static rtx_insn *find_dead_or_set_registers (rtx_insn *, struct resources*, |
| rtx *, int, struct resources, |
| struct resources); |
| |
| /* Utility function called from mark_target_live_regs via note_stores. |
| It deadens any CLOBBERed registers and livens any SET registers. */ |
| |
| static void |
| update_live_status (rtx dest, const_rtx x, void *data ATTRIBUTE_UNUSED) |
| { |
| int first_regno, last_regno; |
| int i; |
| |
| if (!REG_P (dest) |
| && (GET_CODE (dest) != SUBREG || !REG_P (SUBREG_REG (dest)))) |
| return; |
| |
| if (GET_CODE (dest) == SUBREG) |
| { |
| first_regno = subreg_regno (dest); |
| last_regno = first_regno + subreg_nregs (dest); |
| |
| } |
| else |
| { |
| first_regno = REGNO (dest); |
| last_regno = END_HARD_REGNO (dest); |
| } |
| |
| if (GET_CODE (x) == CLOBBER) |
| for (i = first_regno; i < last_regno; i++) |
| CLEAR_HARD_REG_BIT (current_live_regs, i); |
| else |
| for (i = first_regno; i < last_regno; i++) |
| { |
| SET_HARD_REG_BIT (current_live_regs, i); |
| CLEAR_HARD_REG_BIT (pending_dead_regs, i); |
| } |
| } |
| |
| /* Find the number of the basic block with correct live register |
| information that starts closest to INSN. Return -1 if we couldn't |
| find such a basic block or the beginning is more than |
| SEARCH_LIMIT instructions before INSN. Use SEARCH_LIMIT = -1 for |
| an unlimited search. |
| |
| The delay slot filling code destroys the control-flow graph so, |
| instead of finding the basic block containing INSN, we search |
| backwards toward a BARRIER where the live register information is |
| correct. */ |
| |
| static int |
| find_basic_block (rtx_insn *insn, int search_limit) |
| { |
| /* Scan backwards to the previous BARRIER. Then see if we can find a |
| label that starts a basic block. Return the basic block number. */ |
| for (insn = prev_nonnote_insn (insn); |
| insn && !BARRIER_P (insn) && search_limit != 0; |
| insn = prev_nonnote_insn (insn), --search_limit) |
| ; |
| |
| /* The closest BARRIER is too far away. */ |
| if (search_limit == 0) |
| return -1; |
| |
| /* The start of the function. */ |
| else if (insn == 0) |
| return ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb->index; |
| |
| /* See if any of the upcoming CODE_LABELs start a basic block. If we reach |
| anything other than a CODE_LABEL or note, we can't find this code. */ |
| for (insn = next_nonnote_insn (insn); |
| insn && LABEL_P (insn); |
| insn = next_nonnote_insn (insn)) |
| if (BLOCK_FOR_INSN (insn)) |
| return BLOCK_FOR_INSN (insn)->index; |
| |
| return -1; |
| } |
| |
| /* Similar to next_insn, but ignores insns in the delay slots of |
| an annulled branch. */ |
| |
| static rtx_insn * |
| next_insn_no_annul (rtx_insn *insn) |
| { |
| if (insn) |
| { |
| /* If INSN is an annulled branch, skip any insns from the target |
| of the branch. */ |
| if (JUMP_P (insn) |
| && INSN_ANNULLED_BRANCH_P (insn) |
| && NEXT_INSN (PREV_INSN (insn)) != insn) |
| { |
| rtx_insn *next = NEXT_INSN (insn); |
| |
| while ((NONJUMP_INSN_P (next) || JUMP_P (next) || CALL_P (next)) |
| && INSN_FROM_TARGET_P (next)) |
| { |
| insn = next; |
| next = NEXT_INSN (insn); |
| } |
| } |
| |
| insn = NEXT_INSN (insn); |
| if (insn && NONJUMP_INSN_P (insn) |
| && GET_CODE (PATTERN (insn)) == SEQUENCE) |
| insn = as_a <rtx_sequence *> (PATTERN (insn))->insn (0); |
| } |
| |
| return insn; |
| } |
| |
| /* Given X, some rtl, and RES, a pointer to a `struct resource', mark |
| which resources are referenced by the insn. If INCLUDE_DELAYED_EFFECTS |
| is TRUE, resources used by the called routine will be included for |
| CALL_INSNs. */ |
| |
| void |
| mark_referenced_resources (rtx x, struct resources *res, |
| bool include_delayed_effects) |
| { |
| enum rtx_code code = GET_CODE (x); |
| int i, j; |
| unsigned int r; |
| const char *format_ptr; |
| |
| /* Handle leaf items for which we set resource flags. Also, special-case |
| CALL, SET and CLOBBER operators. */ |
| switch (code) |
| { |
| case CONST: |
| CASE_CONST_ANY: |
| case PC: |
| case SYMBOL_REF: |
| case LABEL_REF: |
| return; |
| |
| case SUBREG: |
| if (!REG_P (SUBREG_REG (x))) |
| mark_referenced_resources (SUBREG_REG (x), res, false); |
| else |
| { |
| unsigned int regno = subreg_regno (x); |
| unsigned int last_regno = regno + subreg_nregs (x); |
| |
| gcc_assert (last_regno <= FIRST_PSEUDO_REGISTER); |
| for (r = regno; r < last_regno; r++) |
| SET_HARD_REG_BIT (res->regs, r); |
| } |
| return; |
| |
| case REG: |
| gcc_assert (HARD_REGISTER_P (x)); |
| add_to_hard_reg_set (&res->regs, GET_MODE (x), REGNO (x)); |
| return; |
| |
| case MEM: |
| /* If this memory shouldn't change, it really isn't referencing |
| memory. */ |
| if (! MEM_READONLY_P (x)) |
| res->memory = 1; |
| res->volatil |= MEM_VOLATILE_P (x); |
| |
| /* Mark registers used to access memory. */ |
| mark_referenced_resources (XEXP (x, 0), res, false); |
| return; |
| |
| case CC0: |
| res->cc = 1; |
| return; |
| |
| case UNSPEC_VOLATILE: |
| case TRAP_IF: |
| case ASM_INPUT: |
| /* Traditional asm's are always volatile. */ |
| res->volatil = 1; |
| break; |
| |
| case ASM_OPERANDS: |
| res->volatil |= MEM_VOLATILE_P (x); |
| |
| /* For all ASM_OPERANDS, we must traverse the vector of input operands. |
| We can not just fall through here since then we would be confused |
| by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate |
| traditional asms unlike their normal usage. */ |
| |
| for (i = 0; i < ASM_OPERANDS_INPUT_LENGTH (x); i++) |
| mark_referenced_resources (ASM_OPERANDS_INPUT (x, i), res, false); |
| return; |
| |
| case CALL: |
| /* The first operand will be a (MEM (xxx)) but doesn't really reference |
| memory. The second operand may be referenced, though. */ |
| mark_referenced_resources (XEXP (XEXP (x, 0), 0), res, false); |
| mark_referenced_resources (XEXP (x, 1), res, false); |
| return; |
| |
| case SET: |
| /* Usually, the first operand of SET is set, not referenced. But |
| registers used to access memory are referenced. SET_DEST is |
| also referenced if it is a ZERO_EXTRACT. */ |
| |
| mark_referenced_resources (SET_SRC (x), res, false); |
| |
| x = SET_DEST (x); |
| if (GET_CODE (x) == ZERO_EXTRACT |
| || GET_CODE (x) == STRICT_LOW_PART) |
| mark_referenced_resources (x, res, false); |
| else if (GET_CODE (x) == SUBREG) |
| x = SUBREG_REG (x); |
| if (MEM_P (x)) |
| mark_referenced_resources (XEXP (x, 0), res, false); |
| return; |
| |
| case CLOBBER: |
| return; |
| |
| case CALL_INSN: |
| if (include_delayed_effects) |
| { |
| /* A CALL references memory, the frame pointer if it exists, the |
| stack pointer, any global registers and any registers given in |
| USE insns immediately in front of the CALL. |
| |
| However, we may have moved some of the parameter loading insns |
| into the delay slot of this CALL. If so, the USE's for them |
| don't count and should be skipped. */ |
| rtx_insn *insn = PREV_INSN (as_a <rtx_insn *> (x)); |
| rtx_sequence *sequence = 0; |
| int seq_size = 0; |
| int i; |
| |
| /* If we are part of a delay slot sequence, point at the SEQUENCE. */ |
| if (NEXT_INSN (insn) != x) |
| { |
| sequence = as_a <rtx_sequence *> (PATTERN (NEXT_INSN (insn))); |
| seq_size = sequence->len (); |
| gcc_assert (GET_CODE (sequence) == SEQUENCE); |
| } |
| |
| res->memory = 1; |
| SET_HARD_REG_BIT (res->regs, STACK_POINTER_REGNUM); |
| if (frame_pointer_needed) |
| { |
| SET_HARD_REG_BIT (res->regs, FRAME_POINTER_REGNUM); |
| #if !HARD_FRAME_POINTER_IS_FRAME_POINTER |
| SET_HARD_REG_BIT (res->regs, HARD_FRAME_POINTER_REGNUM); |
| #endif |
| } |
| |
| for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
| if (global_regs[i]) |
| SET_HARD_REG_BIT (res->regs, i); |
| |
| /* Check for a REG_SETJMP. If it exists, then we must |
| assume that this call can need any register. |
| |
| This is done to be more conservative about how we handle setjmp. |
| We assume that they both use and set all registers. Using all |
| registers ensures that a register will not be considered dead |
| just because it crosses a setjmp call. A register should be |
| considered dead only if the setjmp call returns nonzero. */ |
| if (find_reg_note (x, REG_SETJMP, NULL)) |
| SET_HARD_REG_SET (res->regs); |
| |
| { |
| rtx link; |
| |
| for (link = CALL_INSN_FUNCTION_USAGE (x); |
| link; |
| link = XEXP (link, 1)) |
| if (GET_CODE (XEXP (link, 0)) == USE) |
| { |
| for (i = 1; i < seq_size; i++) |
| { |
| rtx slot_pat = PATTERN (sequence->element (i)); |
| if (GET_CODE (slot_pat) == SET |
| && rtx_equal_p (SET_DEST (slot_pat), |
| XEXP (XEXP (link, 0), 0))) |
| break; |
| } |
| if (i >= seq_size) |
| mark_referenced_resources (XEXP (XEXP (link, 0), 0), |
| res, false); |
| } |
| } |
| } |
| |
| /* ... fall through to other INSN processing ... */ |
| |
| case INSN: |
| case JUMP_INSN: |
| |
| if (GET_CODE (PATTERN (x)) == COND_EXEC) |
| /* In addition to the usual references, also consider all outputs |
| as referenced, to compensate for mark_set_resources treating |
| them as killed. This is similar to ZERO_EXTRACT / STRICT_LOW_PART |
| handling, execpt that we got a partial incidence instead of a partial |
| width. */ |
| mark_set_resources (x, res, 0, |
| include_delayed_effects |
| ? MARK_SRC_DEST_CALL : MARK_SRC_DEST); |
| |
| #ifdef INSN_REFERENCES_ARE_DELAYED |
| if (! include_delayed_effects |
| && INSN_REFERENCES_ARE_DELAYED (as_a <rtx_insn *> (x))) |
| return; |
| #endif |
| |
| /* No special processing, just speed up. */ |
| mark_referenced_resources (PATTERN (x), res, include_delayed_effects); |
| return; |
| |
| default: |
| break; |
| } |
| |
| /* Process each sub-expression and flag what it needs. */ |
| format_ptr = GET_RTX_FORMAT (code); |
| for (i = 0; i < GET_RTX_LENGTH (code); i++) |
| switch (*format_ptr++) |
| { |
| case 'e': |
| mark_referenced_resources (XEXP (x, i), res, include_delayed_effects); |
| break; |
| |
| case 'E': |
| for (j = 0; j < XVECLEN (x, i); j++) |
| mark_referenced_resources (XVECEXP (x, i, j), res, |
| include_delayed_effects); |
| break; |
| } |
| } |
| |
| /* A subroutine of mark_target_live_regs. Search forward from TARGET |
| looking for registers that are set before they are used. These are dead. |
| Stop after passing a few conditional jumps, and/or a small |
| number of unconditional branches. */ |
| |
| static rtx_insn * |
| find_dead_or_set_registers (rtx_insn *target, struct resources *res, |
| rtx *jump_target, int jump_count, |
| struct resources set, struct resources needed) |
| { |
| HARD_REG_SET scratch; |
| rtx_insn *insn; |
| rtx_insn *next_insn; |
| rtx_insn *jump_insn = 0; |
| int i; |
| |
| for (insn = target; insn; insn = next_insn) |
| { |
| rtx_insn *this_jump_insn = insn; |
| |
| next_insn = NEXT_INSN (insn); |
| |
| /* If this instruction can throw an exception, then we don't |
| know where we might end up next. That means that we have to |
| assume that whatever we have already marked as live really is |
| live. */ |
| if (can_throw_internal (insn)) |
| break; |
| |
| switch (GET_CODE (insn)) |
| { |
| case CODE_LABEL: |
| /* After a label, any pending dead registers that weren't yet |
| used can be made dead. */ |
| AND_COMPL_HARD_REG_SET (pending_dead_regs, needed.regs); |
| AND_COMPL_HARD_REG_SET (res->regs, pending_dead_regs); |
| CLEAR_HARD_REG_SET (pending_dead_regs); |
| |
| continue; |
| |
| case BARRIER: |
| case NOTE: |
| continue; |
| |
| case INSN: |
| if (GET_CODE (PATTERN (insn)) == USE) |
| { |
| /* If INSN is a USE made by update_block, we care about the |
| underlying insn. Any registers set by the underlying insn |
| are live since the insn is being done somewhere else. */ |
| if (INSN_P (XEXP (PATTERN (insn), 0))) |
| mark_set_resources (XEXP (PATTERN (insn), 0), res, 0, |
| MARK_SRC_DEST_CALL); |
| |
| /* All other USE insns are to be ignored. */ |
| continue; |
| } |
| else if (GET_CODE (PATTERN (insn)) == CLOBBER) |
| continue; |
| else if (rtx_sequence *seq = |
| dyn_cast <rtx_sequence *> (PATTERN (insn))) |
| { |
| /* An unconditional jump can be used to fill the delay slot |
| of a call, so search for a JUMP_INSN in any position. */ |
| for (i = 0; i < seq->len (); i++) |
| { |
| this_jump_insn = seq->insn (i); |
| if (JUMP_P (this_jump_insn)) |
| break; |
| } |
| } |
| |
| default: |
| break; |
| } |
| |
| if (JUMP_P (this_jump_insn)) |
| { |
| if (jump_count++ < 10) |
| { |
| if (any_uncondjump_p (this_jump_insn) |
| || ANY_RETURN_P (PATTERN (this_jump_insn))) |
| { |
| rtx lab_or_return = JUMP_LABEL (this_jump_insn); |
| if (ANY_RETURN_P (lab_or_return)) |
| next_insn = NULL; |
| else |
| next_insn = as_a <rtx_insn *> (lab_or_return); |
| if (jump_insn == 0) |
| { |
| jump_insn = insn; |
| if (jump_target) |
| *jump_target = JUMP_LABEL (this_jump_insn); |
| } |
| } |
| else if (any_condjump_p (this_jump_insn)) |
| { |
| struct resources target_set, target_res; |
| struct resources fallthrough_res; |
| |
| /* We can handle conditional branches here by following |
| both paths, and then IOR the results of the two paths |
| together, which will give us registers that are dead |
| on both paths. Since this is expensive, we give it |
| a much higher cost than unconditional branches. The |
| cost was chosen so that we will follow at most 1 |
| conditional branch. */ |
| |
| jump_count += 4; |
| if (jump_count >= 10) |
| break; |
| |
| mark_referenced_resources (insn, &needed, true); |
| |
| /* For an annulled branch, mark_set_resources ignores slots |
| filled by instructions from the target. This is correct |
| if the branch is not taken. Since we are following both |
| paths from the branch, we must also compute correct info |
| if the branch is taken. We do this by inverting all of |
| the INSN_FROM_TARGET_P bits, calling mark_set_resources, |
| and then inverting the INSN_FROM_TARGET_P bits again. */ |
| |
| if (GET_CODE (PATTERN (insn)) == SEQUENCE |
| && INSN_ANNULLED_BRANCH_P (this_jump_insn)) |
| { |
| rtx_sequence *seq = as_a <rtx_sequence *> (PATTERN (insn)); |
| for (i = 1; i < seq->len (); i++) |
| INSN_FROM_TARGET_P (seq->element (i)) |
| = ! INSN_FROM_TARGET_P (seq->element (i)); |
| |
| target_set = set; |
| mark_set_resources (insn, &target_set, 0, |
| MARK_SRC_DEST_CALL); |
| |
| for (i = 1; i < seq->len (); i++) |
| INSN_FROM_TARGET_P (seq->element (i)) |
| = ! INSN_FROM_TARGET_P (seq->element (i)); |
| |
| mark_set_resources (insn, &set, 0, MARK_SRC_DEST_CALL); |
| } |
| else |
| { |
| mark_set_resources (insn, &set, 0, MARK_SRC_DEST_CALL); |
| target_set = set; |
| } |
| |
| target_res = *res; |
| COPY_HARD_REG_SET (scratch, target_set.regs); |
| AND_COMPL_HARD_REG_SET (scratch, needed.regs); |
| AND_COMPL_HARD_REG_SET (target_res.regs, scratch); |
| |
| fallthrough_res = *res; |
| COPY_HARD_REG_SET (scratch, set.regs); |
| AND_COMPL_HARD_REG_SET (scratch, needed.regs); |
| AND_COMPL_HARD_REG_SET (fallthrough_res.regs, scratch); |
| |
| if (!ANY_RETURN_P (JUMP_LABEL (this_jump_insn))) |
| find_dead_or_set_registers (JUMP_LABEL_AS_INSN (this_jump_insn), |
| &target_res, 0, jump_count, |
| target_set, needed); |
| find_dead_or_set_registers (next_insn, |
| &fallthrough_res, 0, jump_count, |
| set, needed); |
| IOR_HARD_REG_SET (fallthrough_res.regs, target_res.regs); |
| AND_HARD_REG_SET (res->regs, fallthrough_res.regs); |
| break; |
| } |
| else |
| break; |
| } |
| else |
| { |
| /* Don't try this optimization if we expired our jump count |
| above, since that would mean there may be an infinite loop |
| in the function being compiled. */ |
| jump_insn = 0; |
| break; |
| } |
| } |
| |
| mark_referenced_resources (insn, &needed, true); |
| mark_set_resources (insn, &set, 0, MARK_SRC_DEST_CALL); |
| |
| COPY_HARD_REG_SET (scratch, set.regs); |
| AND_COMPL_HARD_REG_SET (scratch, needed.regs); |
| AND_COMPL_HARD_REG_SET (res->regs, scratch); |
| } |
| |
| return jump_insn; |
| } |
| |
| /* Given X, a part of an insn, and a pointer to a `struct resource', |
| RES, indicate which resources are modified by the insn. If |
| MARK_TYPE is MARK_SRC_DEST_CALL, also mark resources potentially |
| set by the called routine. |
| |
| If IN_DEST is nonzero, it means we are inside a SET. Otherwise, |
| objects are being referenced instead of set. |
| |
| We never mark the insn as modifying the condition code unless it explicitly |
| SETs CC0 even though this is not totally correct. The reason for this is |
| that we require a SET of CC0 to immediately precede the reference to CC0. |
| So if some other insn sets CC0 as a side-effect, we know it cannot affect |
| our computation and thus may be placed in a delay slot. */ |
| |
| void |
| mark_set_resources (rtx x, struct resources *res, int in_dest, |
| enum mark_resource_type mark_type) |
| { |
| enum rtx_code code; |
| int i, j; |
| unsigned int r; |
| const char *format_ptr; |
| |
| restart: |
| |
| code = GET_CODE (x); |
| |
| switch (code) |
| { |
| case NOTE: |
| case BARRIER: |
| case CODE_LABEL: |
| case USE: |
| CASE_CONST_ANY: |
| case LABEL_REF: |
| case SYMBOL_REF: |
| case CONST: |
| case PC: |
| /* These don't set any resources. */ |
| return; |
| |
| case CC0: |
| if (in_dest) |
| res->cc = 1; |
| return; |
| |
| case CALL_INSN: |
| /* Called routine modifies the condition code, memory, any registers |
| that aren't saved across calls, global registers and anything |
| explicitly CLOBBERed immediately after the CALL_INSN. */ |
| |
| if (mark_type == MARK_SRC_DEST_CALL) |
| { |
| rtx_call_insn *call_insn = as_a <rtx_call_insn *> (x); |
| rtx link; |
| HARD_REG_SET regs; |
| |
| res->cc = res->memory = 1; |
| |
| get_call_reg_set_usage (call_insn, ®s, regs_invalidated_by_call); |
| IOR_HARD_REG_SET (res->regs, regs); |
| |
| for (link = CALL_INSN_FUNCTION_USAGE (call_insn); |
| link; link = XEXP (link, 1)) |
| if (GET_CODE (XEXP (link, 0)) == CLOBBER) |
| mark_set_resources (SET_DEST (XEXP (link, 0)), res, 1, |
| MARK_SRC_DEST); |
| |
| /* Check for a REG_SETJMP. If it exists, then we must |
| assume that this call can clobber any register. */ |
| if (find_reg_note (call_insn, REG_SETJMP, NULL)) |
| SET_HARD_REG_SET (res->regs); |
| } |
| |
| /* ... and also what its RTL says it modifies, if anything. */ |
| |
| case JUMP_INSN: |
| case INSN: |
| |
| /* An insn consisting of just a CLOBBER (or USE) is just for flow |
| and doesn't actually do anything, so we ignore it. */ |
| |
| #ifdef INSN_SETS_ARE_DELAYED |
| if (mark_type != MARK_SRC_DEST_CALL |
| && INSN_SETS_ARE_DELAYED (as_a <rtx_insn *> (x))) |
| return; |
| #endif |
| |
| x = PATTERN (x); |
| if (GET_CODE (x) != USE && GET_CODE (x) != CLOBBER) |
| goto restart; |
| return; |
| |
| case SET: |
| /* If the source of a SET is a CALL, this is actually done by |
| the called routine. So only include it if we are to include the |
| effects of the calling routine. */ |
| |
| mark_set_resources (SET_DEST (x), res, |
| (mark_type == MARK_SRC_DEST_CALL |
| || GET_CODE (SET_SRC (x)) != CALL), |
| mark_type); |
| |
| mark_set_resources (SET_SRC (x), res, 0, MARK_SRC_DEST); |
| return; |
| |
| case CLOBBER: |
| mark_set_resources (XEXP (x, 0), res, 1, MARK_SRC_DEST); |
| return; |
| |
| case SEQUENCE: |
| { |
| rtx_sequence *seq = as_a <rtx_sequence *> (x); |
| rtx control = seq->element (0); |
| bool annul_p = JUMP_P (control) && INSN_ANNULLED_BRANCH_P (control); |
| |
| mark_set_resources (control, res, 0, mark_type); |
| for (i = seq->len () - 1; i >= 0; --i) |
| { |
| rtx elt = seq->element (i); |
| if (!annul_p && INSN_FROM_TARGET_P (elt)) |
| mark_set_resources (elt, res, 0, mark_type); |
| } |
| } |
| return; |
| |
| case POST_INC: |
| case PRE_INC: |
| case POST_DEC: |
| case PRE_DEC: |
| mark_set_resources (XEXP (x, 0), res, 1, MARK_SRC_DEST); |
| return; |
| |
| case PRE_MODIFY: |
| case POST_MODIFY: |
| mark_set_resources (XEXP (x, 0), res, 1, MARK_SRC_DEST); |
| mark_set_resources (XEXP (XEXP (x, 1), 0), res, 0, MARK_SRC_DEST); |
| mark_set_resources (XEXP (XEXP (x, 1), 1), res, 0, MARK_SRC_DEST); |
| return; |
| |
| case SIGN_EXTRACT: |
| case ZERO_EXTRACT: |
| mark_set_resources (XEXP (x, 0), res, in_dest, MARK_SRC_DEST); |
| mark_set_resources (XEXP (x, 1), res, 0, MARK_SRC_DEST); |
| mark_set_resources (XEXP (x, 2), res, 0, MARK_SRC_DEST); |
| return; |
| |
| case MEM: |
| if (in_dest) |
| { |
| res->memory = 1; |
| res->volatil |= MEM_VOLATILE_P (x); |
| } |
| |
| mark_set_resources (XEXP (x, 0), res, 0, MARK_SRC_DEST); |
| return; |
| |
| case SUBREG: |
| if (in_dest) |
| { |
| if (!REG_P (SUBREG_REG (x))) |
| mark_set_resources (SUBREG_REG (x), res, in_dest, mark_type); |
| else |
| { |
| unsigned int regno = subreg_regno (x); |
| unsigned int last_regno = regno + subreg_nregs (x); |
| |
| gcc_assert (last_regno <= FIRST_PSEUDO_REGISTER); |
| for (r = regno; r < last_regno; r++) |
| SET_HARD_REG_BIT (res->regs, r); |
| } |
| } |
| return; |
| |
| case REG: |
| if (in_dest) |
| { |
| gcc_assert (HARD_REGISTER_P (x)); |
| add_to_hard_reg_set (&res->regs, GET_MODE (x), REGNO (x)); |
| } |
| return; |
| |
| case UNSPEC_VOLATILE: |
| case ASM_INPUT: |
| /* Traditional asm's are always volatile. */ |
| res->volatil = 1; |
| return; |
| |
| case TRAP_IF: |
| res->volatil = 1; |
| break; |
| |
| case ASM_OPERANDS: |
| res->volatil |= MEM_VOLATILE_P (x); |
| |
| /* For all ASM_OPERANDS, we must traverse the vector of input operands. |
| We can not just fall through here since then we would be confused |
| by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate |
| traditional asms unlike their normal usage. */ |
| |
| for (i = 0; i < ASM_OPERANDS_INPUT_LENGTH (x); i++) |
| mark_set_resources (ASM_OPERANDS_INPUT (x, i), res, in_dest, |
| MARK_SRC_DEST); |
| return; |
| |
| default: |
| break; |
| } |
| |
| /* Process each sub-expression and flag what it needs. */ |
| format_ptr = GET_RTX_FORMAT (code); |
| for (i = 0; i < GET_RTX_LENGTH (code); i++) |
| switch (*format_ptr++) |
| { |
| case 'e': |
| mark_set_resources (XEXP (x, i), res, in_dest, mark_type); |
| break; |
| |
| case 'E': |
| for (j = 0; j < XVECLEN (x, i); j++) |
| mark_set_resources (XVECEXP (x, i, j), res, in_dest, mark_type); |
| break; |
| } |
| } |
| |
| /* Return TRUE if INSN is a return, possibly with a filled delay slot. */ |
| |
| static bool |
| return_insn_p (const_rtx insn) |
| { |
| if (JUMP_P (insn) && ANY_RETURN_P (PATTERN (insn))) |
| return true; |
| |
| if (NONJUMP_INSN_P (insn) && GET_CODE (PATTERN (insn)) == SEQUENCE) |
| return return_insn_p (XVECEXP (PATTERN (insn), 0, 0)); |
| |
| return false; |
| } |
| |
| /* Set the resources that are live at TARGET. |
| |
| If TARGET is zero, we refer to the end of the current function and can |
| return our precomputed value. |
| |
| Otherwise, we try to find out what is live by consulting the basic block |
| information. This is tricky, because we must consider the actions of |
| reload and jump optimization, which occur after the basic block information |
| has been computed. |
| |
| Accordingly, we proceed as follows:: |
| |
| We find the previous BARRIER and look at all immediately following labels |
| (with no intervening active insns) to see if any of them start a basic |
| block. If we hit the start of the function first, we use block 0. |
| |
| Once we have found a basic block and a corresponding first insn, we can |
| accurately compute the live status (by starting at a label following a |
| BARRIER, we are immune to actions taken by reload and jump.) Then we |
| scan all insns between that point and our target. For each CLOBBER (or |
| for call-clobbered regs when we pass a CALL_INSN), mark the appropriate |
| registers are dead. For a SET, mark them as live. |
| |
| We have to be careful when using REG_DEAD notes because they are not |
| updated by such things as find_equiv_reg. So keep track of registers |
| marked as dead that haven't been assigned to, and mark them dead at the |
| next CODE_LABEL since reload and jump won't propagate values across labels. |
| |
| If we cannot find the start of a basic block (should be a very rare |
| case, if it can happen at all), mark everything as potentially live. |
| |
| Next, scan forward from TARGET looking for things set or clobbered |
| before they are used. These are not live. |
| |
| Because we can be called many times on the same target, save our results |
| in a hash table indexed by INSN_UID. This is only done if the function |
| init_resource_info () was invoked before we are called. */ |
| |
| void |
| mark_target_live_regs (rtx_insn *insns, rtx target_maybe_return, struct resources *res) |
| { |
| int b = -1; |
| unsigned int i; |
| struct target_info *tinfo = NULL; |
| rtx_insn *insn; |
| rtx jump_insn = 0; |
| rtx jump_target; |
| HARD_REG_SET scratch; |
| struct resources set, needed; |
| |
| /* Handle end of function. */ |
| if (target_maybe_return == 0 || ANY_RETURN_P (target_maybe_return)) |
| { |
| *res = end_of_function_needs; |
| return; |
| } |
| |
| /* We've handled the case of RETURN/SIMPLE_RETURN; we should now have an |
| instruction. */ |
| rtx_insn *target = as_a <rtx_insn *> (target_maybe_return); |
| |
| /* Handle return insn. */ |
| if (return_insn_p (target)) |
| { |
| *res = end_of_function_needs; |
| mark_referenced_resources (target, res, false); |
| return; |
| } |
| |
| /* We have to assume memory is needed, but the CC isn't. */ |
| res->memory = 1; |
| res->volatil = 0; |
| res->cc = 0; |
| |
| /* See if we have computed this value already. */ |
| if (target_hash_table != NULL) |
| { |
| for (tinfo = target_hash_table[INSN_UID (target) % TARGET_HASH_PRIME]; |
| tinfo; tinfo = tinfo->next) |
| if (tinfo->uid == INSN_UID (target)) |
| break; |
| |
| /* Start by getting the basic block number. If we have saved |
| information, we can get it from there unless the insn at the |
| start of the basic block has been deleted. */ |
| if (tinfo && tinfo->block != -1 |
| && ! BB_HEAD (BASIC_BLOCK_FOR_FN (cfun, tinfo->block))->deleted ()) |
| b = tinfo->block; |
| } |
| |
| if (b == -1) |
| b = find_basic_block (target, MAX_DELAY_SLOT_LIVE_SEARCH); |
| |
| if (target_hash_table != NULL) |
| { |
| if (tinfo) |
| { |
| /* If the information is up-to-date, use it. Otherwise, we will |
| update it below. */ |
| if (b == tinfo->block && b != -1 && tinfo->bb_tick == bb_ticks[b]) |
| { |
| COPY_HARD_REG_SET (res->regs, tinfo->live_regs); |
| return; |
| } |
| } |
| else |
| { |
| /* Allocate a place to put our results and chain it into the |
| hash table. */ |
| tinfo = XNEW (struct target_info); |
| tinfo->uid = INSN_UID (target); |
| tinfo->block = b; |
| tinfo->next |
| = target_hash_table[INSN_UID (target) % TARGET_HASH_PRIME]; |
| target_hash_table[INSN_UID (target) % TARGET_HASH_PRIME] = tinfo; |
| } |
| } |
| |
| CLEAR_HARD_REG_SET (pending_dead_regs); |
| |
| /* If we found a basic block, get the live registers from it and update |
| them with anything set or killed between its start and the insn before |
| TARGET; this custom life analysis is really about registers so we need |
| to use the LR problem. Otherwise, we must assume everything is live. */ |
| if (b != -1) |
| { |
| regset regs_live = DF_LR_IN (BASIC_BLOCK_FOR_FN (cfun, b)); |
| rtx_insn *start_insn, *stop_insn; |
| |
| /* Compute hard regs live at start of block. */ |
| REG_SET_TO_HARD_REG_SET (current_live_regs, regs_live); |
| |
| /* Get starting and ending insn, handling the case where each might |
| be a SEQUENCE. */ |
| start_insn = (b == ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb->index ? |
| insns : BB_HEAD (BASIC_BLOCK_FOR_FN (cfun, b))); |
| stop_insn = target; |
| |
| if (NONJUMP_INSN_P (start_insn) |
| && GET_CODE (PATTERN (start_insn)) == SEQUENCE) |
| start_insn = as_a <rtx_sequence *> (PATTERN (start_insn))->insn (0); |
| |
| if (NONJUMP_INSN_P (stop_insn) |
| && GET_CODE (PATTERN (stop_insn)) == SEQUENCE) |
| stop_insn = next_insn (PREV_INSN (stop_insn)); |
| |
| for (insn = start_insn; insn != stop_insn; |
| insn = next_insn_no_annul (insn)) |
| { |
| rtx link; |
| rtx_insn *real_insn = insn; |
| enum rtx_code code = GET_CODE (insn); |
| |
| if (DEBUG_INSN_P (insn)) |
| continue; |
| |
| /* If this insn is from the target of a branch, it isn't going to |
| be used in the sequel. If it is used in both cases, this |
| test will not be true. */ |
| if ((code == INSN || code == JUMP_INSN || code == CALL_INSN) |
| && INSN_FROM_TARGET_P (insn)) |
| continue; |
| |
| /* If this insn is a USE made by update_block, we care about the |
| underlying insn. */ |
| if (code == INSN |
| && GET_CODE (PATTERN (insn)) == USE |
| && INSN_P (XEXP (PATTERN (insn), 0))) |
| real_insn = as_a <rtx_insn *> (XEXP (PATTERN (insn), 0)); |
| |
| if (CALL_P (real_insn)) |
| { |
| /* Values in call-clobbered registers survive a COND_EXEC CALL |
| if that is not executed; this matters for resoure use because |
| they may be used by a complementarily (or more strictly) |
| predicated instruction, or if the CALL is NORETURN. */ |
| if (GET_CODE (PATTERN (real_insn)) != COND_EXEC) |
| { |
| HARD_REG_SET regs_invalidated_by_this_call; |
| get_call_reg_set_usage (real_insn, |
| ®s_invalidated_by_this_call, |
| regs_invalidated_by_call); |
| /* CALL clobbers all call-used regs that aren't fixed except |
| sp, ap, and fp. Do this before setting the result of the |
| call live. */ |
| AND_COMPL_HARD_REG_SET (current_live_regs, |
| regs_invalidated_by_this_call); |
| } |
| |
| /* A CALL_INSN sets any global register live, since it may |
| have been modified by the call. */ |
| for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
| if (global_regs[i]) |
| SET_HARD_REG_BIT (current_live_regs, i); |
| } |
| |
| /* Mark anything killed in an insn to be deadened at the next |
| label. Ignore USE insns; the only REG_DEAD notes will be for |
| parameters. But they might be early. A CALL_INSN will usually |
| clobber registers used for parameters. It isn't worth bothering |
| with the unlikely case when it won't. */ |
| if ((NONJUMP_INSN_P (real_insn) |
| && GET_CODE (PATTERN (real_insn)) != USE |
| && GET_CODE (PATTERN (real_insn)) != CLOBBER) |
| || JUMP_P (real_insn) |
| || CALL_P (real_insn)) |
| { |
| for (link = REG_NOTES (real_insn); link; link = XEXP (link, 1)) |
| if (REG_NOTE_KIND (link) == REG_DEAD |
| && REG_P (XEXP (link, 0)) |
| && REGNO (XEXP (link, 0)) < FIRST_PSEUDO_REGISTER) |
| add_to_hard_reg_set (&pending_dead_regs, |
| GET_MODE (XEXP (link, 0)), |
| REGNO (XEXP (link, 0))); |
| |
| note_stores (PATTERN (real_insn), update_live_status, NULL); |
| |
| /* If any registers were unused after this insn, kill them. |
| These notes will always be accurate. */ |
| for (link = REG_NOTES (real_insn); link; link = XEXP (link, 1)) |
| if (REG_NOTE_KIND (link) == REG_UNUSED |
| && REG_P (XEXP (link, 0)) |
| && REGNO (XEXP (link, 0)) < FIRST_PSEUDO_REGISTER) |
| remove_from_hard_reg_set (¤t_live_regs, |
| GET_MODE (XEXP (link, 0)), |
| REGNO (XEXP (link, 0))); |
| } |
| |
| else if (LABEL_P (real_insn)) |
| { |
| basic_block bb; |
| |
| /* A label clobbers the pending dead registers since neither |
| reload nor jump will propagate a value across a label. */ |
| AND_COMPL_HARD_REG_SET (current_live_regs, pending_dead_regs); |
| CLEAR_HARD_REG_SET (pending_dead_regs); |
| |
| /* We must conservatively assume that all registers that used |
| to be live here still are. The fallthrough edge may have |
| left a live register uninitialized. */ |
| bb = BLOCK_FOR_INSN (real_insn); |
| if (bb) |
| { |
| HARD_REG_SET extra_live; |
| |
| REG_SET_TO_HARD_REG_SET (extra_live, DF_LR_IN (bb)); |
| IOR_HARD_REG_SET (current_live_regs, extra_live); |
| } |
| } |
| |
| /* The beginning of the epilogue corresponds to the end of the |
| RTL chain when there are no epilogue insns. Certain resources |
| are implicitly required at that point. */ |
| else if (NOTE_P (real_insn) |
| && NOTE_KIND (real_insn) == NOTE_INSN_EPILOGUE_BEG) |
| IOR_HARD_REG_SET (current_live_regs, start_of_epilogue_needs.regs); |
| } |
| |
| COPY_HARD_REG_SET (res->regs, current_live_regs); |
| if (tinfo != NULL) |
| { |
| tinfo->block = b; |
| tinfo->bb_tick = bb_ticks[b]; |
| } |
| } |
| else |
| /* We didn't find the start of a basic block. Assume everything |
| in use. This should happen only extremely rarely. */ |
| SET_HARD_REG_SET (res->regs); |
| |
| CLEAR_RESOURCE (&set); |
| CLEAR_RESOURCE (&needed); |
| |
| jump_insn = find_dead_or_set_registers (target, res, &jump_target, 0, |
| set, needed); |
| |
| /* If we hit an unconditional branch, we have another way of finding out |
| what is live: we can see what is live at the branch target and include |
| anything used but not set before the branch. We add the live |
| resources found using the test below to those found until now. */ |
| |
| if (jump_insn) |
| { |
| struct resources new_resources; |
| rtx_insn *stop_insn = next_active_insn (jump_insn); |
| |
| if (!ANY_RETURN_P (jump_target)) |
| jump_target = next_active_insn (jump_target); |
| mark_target_live_regs (insns, jump_target, &new_resources); |
| CLEAR_RESOURCE (&set); |
| CLEAR_RESOURCE (&needed); |
| |
| /* Include JUMP_INSN in the needed registers. */ |
| for (insn = target; insn != stop_insn; insn = next_active_insn (insn)) |
| { |
| mark_referenced_resources (insn, &needed, true); |
| |
| COPY_HARD_REG_SET (scratch, needed.regs); |
| AND_COMPL_HARD_REG_SET (scratch, set.regs); |
| IOR_HARD_REG_SET (new_resources.regs, scratch); |
| |
| mark_set_resources (insn, &set, 0, MARK_SRC_DEST_CALL); |
| } |
| |
| IOR_HARD_REG_SET (res->regs, new_resources.regs); |
| } |
| |
| if (tinfo != NULL) |
| { |
| COPY_HARD_REG_SET (tinfo->live_regs, res->regs); |
| } |
| } |
| |
| /* Initialize the resources required by mark_target_live_regs (). |
| This should be invoked before the first call to mark_target_live_regs. */ |
| |
| void |
| init_resource_info (rtx_insn *epilogue_insn) |
| { |
| int i; |
| basic_block bb; |
| |
| /* Indicate what resources are required to be valid at the end of the current |
| function. The condition code never is and memory always is. |
| The stack pointer is needed unless EXIT_IGNORE_STACK is true |
| and there is an epilogue that restores the original stack pointer |
| from the frame pointer. Registers used to return the function value |
| are needed. Registers holding global variables are needed. */ |
| |
| end_of_function_needs.cc = 0; |
| end_of_function_needs.memory = 1; |
| CLEAR_HARD_REG_SET (end_of_function_needs.regs); |
| |
| if (frame_pointer_needed) |
| { |
| SET_HARD_REG_BIT (end_of_function_needs.regs, FRAME_POINTER_REGNUM); |
| #if !HARD_FRAME_POINTER_IS_FRAME_POINTER |
| SET_HARD_REG_BIT (end_of_function_needs.regs, HARD_FRAME_POINTER_REGNUM); |
| #endif |
| } |
| if (!(frame_pointer_needed |
| && EXIT_IGNORE_STACK |
| && epilogue_insn |
| && !crtl->sp_is_unchanging)) |
| SET_HARD_REG_BIT (end_of_function_needs.regs, STACK_POINTER_REGNUM); |
| |
| if (crtl->return_rtx != 0) |
| mark_referenced_resources (crtl->return_rtx, |
| &end_of_function_needs, true); |
| |
| for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
| if (global_regs[i] |
| #ifdef EPILOGUE_USES |
| || EPILOGUE_USES (i) |
| #endif |
| ) |
| SET_HARD_REG_BIT (end_of_function_needs.regs, i); |
| |
| /* The registers required to be live at the end of the function are |
| represented in the flow information as being dead just prior to |
| reaching the end of the function. For example, the return of a value |
| might be represented by a USE of the return register immediately |
| followed by an unconditional jump to the return label where the |
| return label is the end of the RTL chain. The end of the RTL chain |
| is then taken to mean that the return register is live. |
| |
| This sequence is no longer maintained when epilogue instructions are |
| added to the RTL chain. To reconstruct the original meaning, the |
| start of the epilogue (NOTE_INSN_EPILOGUE_BEG) is regarded as the |
| point where these registers become live (start_of_epilogue_needs). |
| If epilogue instructions are present, the registers set by those |
| instructions won't have been processed by flow. Thus, those |
| registers are additionally required at the end of the RTL chain |
| (end_of_function_needs). */ |
| |
| start_of_epilogue_needs = end_of_function_needs; |
| |
| while ((epilogue_insn = next_nonnote_insn (epilogue_insn))) |
| { |
| mark_set_resources (epilogue_insn, &end_of_function_needs, 0, |
| MARK_SRC_DEST_CALL); |
| if (return_insn_p (epilogue_insn)) |
| break; |
| } |
| |
| /* Allocate and initialize the tables used by mark_target_live_regs. */ |
| target_hash_table = XCNEWVEC (struct target_info *, TARGET_HASH_PRIME); |
| bb_ticks = XCNEWVEC (int, last_basic_block_for_fn (cfun)); |
| |
| /* Set the BLOCK_FOR_INSN of each label that starts a basic block. */ |
| FOR_EACH_BB_FN (bb, cfun) |
| if (LABEL_P (BB_HEAD (bb))) |
| BLOCK_FOR_INSN (BB_HEAD (bb)) = bb; |
| } |
| |
| /* Free up the resources allocated to mark_target_live_regs (). This |
| should be invoked after the last call to mark_target_live_regs (). */ |
| |
| void |
| free_resource_info (void) |
| { |
| basic_block bb; |
| |
| if (target_hash_table != NULL) |
| { |
| int i; |
| |
| for (i = 0; i < TARGET_HASH_PRIME; ++i) |
| { |
| struct target_info *ti = target_hash_table[i]; |
| |
| while (ti) |
| { |
| struct target_info *next = ti->next; |
| free (ti); |
| ti = next; |
| } |
| } |
| |
| free (target_hash_table); |
| target_hash_table = NULL; |
| } |
| |
| if (bb_ticks != NULL) |
| { |
| free (bb_ticks); |
| bb_ticks = NULL; |
| } |
| |
| FOR_EACH_BB_FN (bb, cfun) |
| if (LABEL_P (BB_HEAD (bb))) |
| BLOCK_FOR_INSN (BB_HEAD (bb)) = NULL; |
| } |
| |
| /* Clear any hashed information that we have stored for INSN. */ |
| |
| void |
| clear_hashed_info_for_insn (rtx_insn *insn) |
| { |
| struct target_info *tinfo; |
| |
| if (target_hash_table != NULL) |
| { |
| for (tinfo = target_hash_table[INSN_UID (insn) % TARGET_HASH_PRIME]; |
| tinfo; tinfo = tinfo->next) |
| if (tinfo->uid == INSN_UID (insn)) |
| break; |
| |
| if (tinfo) |
| tinfo->block = -1; |
| } |
| } |
| |
| /* Increment the tick count for the basic block that contains INSN. */ |
| |
| void |
| incr_ticks_for_insn (rtx_insn *insn) |
| { |
| int b = find_basic_block (insn, MAX_DELAY_SLOT_LIVE_SEARCH); |
| |
| if (b != -1) |
| bb_ticks[b]++; |
| } |
| |
| /* Add TRIAL to the set of resources used at the end of the current |
| function. */ |
| void |
| mark_end_of_function_resources (rtx trial, bool include_delayed_effects) |
| { |
| mark_referenced_resources (trial, &end_of_function_needs, |
| include_delayed_effects); |
| } |