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Diffstat (limited to 'gcc/df-byte-scan.c')
| -rw-r--r-- | gcc/df-byte-scan.c | 340 |
1 files changed, 0 insertions, 340 deletions
diff --git a/gcc/df-byte-scan.c b/gcc/df-byte-scan.c deleted file mode 100644 index 8271465..0000000 --- a/gcc/df-byte-scan.c +++ /dev/null @@ -1,340 +0,0 @@ -/* Scanning of rtl byte level scanning for dataflow analysis. - Copyright (C) 2008 Free Software Foundation, Inc. - Contributed by Kenneth Zadeck (zadeck@naturalbridge.com). - -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 "rtl.h" -#include "tm_p.h" -#include "df.h" -#include "output.h" -#include "dbgcnt.h" - -/* The following suite of functions provides bytewise modeling of REFs - which are struct df_ref. START_BYTE and LAST_BYTE are returned. - These can be used as indexes into bitmaps. The indexes are - normalized so that 0 is the lowest numbered byte, of the inner - register according to the natural ordering of the machine. - - This code is designed to be used in backwards scans (which is, of - course, the way all dataflow scanning should really be done). It - would require a lot of reworking of the api to make it work in a - forwards scanning world. */ - - -/* Helper for df_compute_accessed_bytes. Ref is some sort of extract. - Return true if this effects the entire reg in REF. Return false if - otherwise and set START_BYTE and LAST_BYTE. See the description of - df_compute_accessed_bytes for a description of MM. */ - -static bool -df_compute_accessed_bytes_extract (df_ref ref, - enum df_mm mm , - unsigned int *start_byte, - unsigned int *last_byte) -{ - int start; - int last; - rtx reg = DF_REF_REG (ref); - enum machine_mode m1; - int m1_size; - enum machine_mode m2; - int m2_size; - - /* (*_extract:M1 (reg:M2 X) WIDTH POS) - (*_extract:M1 (subreg:M1 (reg:M2 X N) WIDTH POS) - - This is a bitfield extraction. The assignment clobbers/extracts - exactly the bits named by WIDTH and POS and does not affect the - other bits in register X. It is also technically possible that - the bits asked for are longer than units per word. */ - - int offset = DF_REF_EXTRACT_OFFSET (ref); - int width = DF_REF_EXTRACT_WIDTH (ref); - - if (width == -1 || offset == -1) - return true; - - m1 = DF_REF_EXTRACT_MODE (ref); - m1_size = GET_MODE_SIZE (m1); - - gcc_assert (m1_size <= UNITS_PER_WORD); - - /* There is nothing to do if this is a pure big or small endian - machine, but if the machine is a pastiche, we have to convert the - bit offsets into byte offsets. This is only possible because we - do not care about individual bits because this conversion may - make the bits non-contiguous. */ - if (BYTES_BIG_ENDIAN != BITS_BIG_ENDIAN) - offset = GET_MODE_BITSIZE (m1_size) - (offset + width); - - /* The offset is now in the same order as the subreg_byte. */ - if (GET_CODE (reg) == SUBREG) - { - m2 = GET_MODE (SUBREG_REG (reg)); - m2_size = GET_MODE_SIZE (m2); - if (m1_size > m2_size) - /* If it is paradoxical, subreg_byte will be zero. */ - offset -= subreg_lowpart_offset (m2, m1) * BITS_PER_UNIT; - else - offset += SUBREG_BYTE (reg) * BITS_PER_UNIT; - } - else - { - m2 = GET_MODE (reg); - m2_size = GET_MODE_SIZE (m2); - } - - if (mm == DF_MM_MUST) - { - /* For defs (generally), count the byte only if the whole byte - is touched. */ - start = (offset + BITS_PER_UNIT - 1) / BITS_PER_UNIT; - last = (width + offset) / BITS_PER_UNIT; - - /* In the case where there is nothing, start may be one larger - than last, we canonize this to return zeros. This keeps - computations of length from being negative. */ - if (start >= last) - { - start = 0; - last = 0; - } - } - else - { - /* For uses (generally), count the byte if any part of the byte - is touched. */ - start = offset / BITS_PER_UNIT; - last = (width + offset + BITS_PER_UNIT - 1) / BITS_PER_UNIT; - } - - /* Paradoxical truncation. */ - if (start < 0) - start = 0; - if (last > m2_size) - last = m2_size; - - if (dump_file) - fprintf (dump_file, " cpb extract regno=%d start=%d last=%d\n", - DF_REF_REGNO (ref), start, last); - - *start_byte = start; - *last_byte = last; - return false; -} - - -/* Helper for df_compute_accessed_bytes. Ref is a strict_low_part. - Return true if this effects the entire reg in REF. Return false if - otherwise and set START_BYTE and LAST_BYTE. */ - -static bool -df_compute_accessed_bytes_strict_low_part (df_ref ref, - unsigned int *start_byte, - unsigned int *last_byte) -{ - int start; - int last; - rtx reg = DF_REF_REG (ref); - enum machine_mode m1; - int m1_size; - enum machine_mode m2; - int m2_size; - int offset; - - /* In order to accommodate multiword subregs of a hardreg, df_scan - eats the subreg and it can only be found from the loc. */ - if (REG_P (reg)) - reg = *(DF_REF_LOC (ref)); - - m1 = GET_MODE (reg); - m1_size = GET_MODE_SIZE (m1); - m2 = GET_MODE (SUBREG_REG (reg)); - m2_size = GET_MODE_SIZE (m2); - offset = SUBREG_BYTE (reg); - - /* It does not seem to be meaningful to apply a strict_low_part of a - paradoxical register. */ - gcc_assert (m1_size <= m2_size); - - /* (set (strict_low_part (subreg:M1 (reg:M2 X) N)) ...) - - This is a bitfield insertion. The assignment clobbers exactly the - bits named by the subreg--the M1 bits at position N. It is also - technically possible that the bits asked for are longer than units - per word. */ - - start = offset; - last = offset + m1_size; - - if (dump_file) - fprintf (dump_file, " cpb strict low part regno=%d start=%d last=%d\n", - DF_REF_REGNO (ref), start, last); - - *start_byte = start; - *last_byte = last; - return false; -} - -/* Helper for df_compute_accessed_bytes. Ref is a naked subreg. - Return true if this effects the entire reg in REF. Return false if - otherwise and set START_BYTE and LAST_BYTE. */ - -static bool -df_compute_accessed_bytes_subreg (df_ref ref, unsigned int *start_byte, - unsigned int *last_byte) - -{ - /* (subreg:M1 (reg:M2 X) N) */ - int start; - int last; - rtx reg = DF_REF_REG (ref); - - enum machine_mode m1; - int m1_size; - enum machine_mode m2; - int m2_size; - - /* In order to accommodate multiword subregs of a hardreg, df_scan - eats the subreg and it can only be found from the loc. */ - if (REG_P (reg)) - reg = *(DF_REF_LOC (ref)); - - m1 = GET_MODE (reg); - m1_size = GET_MODE_SIZE (m1); - m2 = GET_MODE (SUBREG_REG (reg)); - m2_size = GET_MODE_SIZE (m2); - - /* A simple paradoxical subreg just accesses the entire inner reg. */ - if (m1_size >= m2_size) - return true; - - /* Defs and uses are different in the amount of the reg that touch. */ - if (DF_REF_REG_DEF_P (ref)) - { - /* This is an lvalue. */ - - if (m2_size > UNITS_PER_WORD) - { - /* The assignment clobbers UNITS_PER_WORD segments of X. - Look at the bytes named by the subreg, and expand it to - cover a UNITS_PER_WORD part of register X. That part of - register X is clobbered, the rest is not. - - E.g., (subreg:SI (reg:DI X) 0), where UNITS_PER_WORD is the - size of SImode, clobbers the first SImode part of X, and does - not affect the second SImode part. - - E.g., (subreg:QI (reg:DI X) 0), where UNITS_PER_WORD is the - size of SImode, clobbers the first SImode part of X, and does - not affect the second SImode part. Here the QImode byte is - expanded to a UNITS_PER_WORD portion of the register for - purposes of determining what is clobbered. - - If this is an rvalue, then it touches just the bytes that it - talks about. */ - int offset = SUBREG_BYTE (reg); - - start = offset & ~(UNITS_PER_WORD - 1); - last = (offset + m1_size + UNITS_PER_WORD - 1) - & ~(UNITS_PER_WORD - 1); - } - else - /* Whole register size M2 equal to or smaller than - UNITS_PER_WORD The assignment clobbers the entire register - X. */ - return true; - } - else - { - /* This is an rvalue. It touches just the bytes they explicitly - mentioned. */ - int offset = SUBREG_BYTE (reg); - start = offset; - last = start + m1_size; - } - - if (dump_file) - fprintf (dump_file, " cpb subreg regno=%d start=%d last=%d\n", - DF_REF_REGNO (ref), start, last); - - *start_byte = start; - *last_byte = last; - return false; -} - - -/* Compute the set of affected bytes by a store to a pseudo to REF. - MM is either DF_MM_MAY or DF_MM_MUST. This is only relevant for - the extracts which are not aligned to byte boundaries. The - DF_MM_MAY returns all of the bytes that any bit is set in and the - DF_MM_MUST returns only the bytes that are completely covered. In - general DF_MM_MAY is used for uses and DF_MM_MUST is used for defs, - but there are exceptions such as the inner loop of the byte level - dead code eliminator which needs DF_MM_MAY for the defs to see if - it any possible bit could be used. - - If the store is to the whole register, just return TRUE, if it is - to part of the register, return FALSE and set START_BYTE and - LAST_BYTE properly. In the case where fabricated uses are passed - in, START_BYTE and LAST_BYTE are set to 0 and false is returned. - This means that this use can be ignored. */ - -bool -df_compute_accessed_bytes (df_ref ref, enum df_mm mm, - unsigned int *start_byte, - unsigned int *last_byte) -{ - if (!dbg_cnt (df_byte_scan)) - return true; - - if (!DF_REF_REG_DEF_P (ref) - && DF_REF_FLAGS_IS_SET (ref, DF_REF_READ_WRITE)) - { - if (DF_REF_FLAGS_IS_SET (ref, DF_REF_PRE_POST_MODIFY)) - /* Pre/post modify/inc/dec always read and write the entire - reg. */ - return true; - else - { - /* DF_REF_READ_WRITE on a use (except for the - DF_REF_PRE_POST_MODIFY) means that this use is fabricated - from a def that is a partial set to a multiword reg. - Here, we only model those cases precisely so the only one - to consider is the use put on a auto inc and dec - insns. */ - *start_byte = 0; - *last_byte = 0; - return false; - } - } - - if (DF_REF_FLAGS_IS_SET (ref, DF_REF_SIGN_EXTRACT | DF_REF_ZERO_EXTRACT)) - return df_compute_accessed_bytes_extract (ref, mm, start_byte, last_byte); - else if (DF_REF_FLAGS_IS_SET (ref, DF_REF_STRICT_LOW_PART)) - return df_compute_accessed_bytes_strict_low_part (ref, - start_byte, last_byte); - else if (GET_CODE (DF_REF_REG (ref)) == SUBREG) - return df_compute_accessed_bytes_subreg (ref, start_byte, last_byte); - return true; -} - |