Author: hailfinger Date: 2009-03-06 01:40:25 +0100 (Fri, 06 Mar 2009) New Revision: 3973
Modified: trunk/util/flashrom/sst28sf040.c Log: During the conversion of flash chip accesses to helper functions, I spotted assignments to volatile variables which were neither placed inside the mmapped ROM area nor were they counters. Due to the use of accessor functions, volatile usage can be reduced significantly because the accessor functions take care of actually performing the reads/writes correctly.
The following semantic patch spotted them (linebreak in python string for readability reasons, please remove before usage): @r exists@ expression b; typedef uint8_t; volatile uint8_t a; position p1; @@ a@p1 = readb(b);
@script:python@ p1 << r.p1; a << r.a; b << r.b; @@ print "* file: %s line %s has assignment to unnecessarily volatile variable: %s = readb(%s);" % (p1[0].file, p1[0].line, a, b)
Result was: HANDLING: sst28sf040.c * file: sst28sf040.c line 44 has assignment to unnecessarily volatile variable: tmp = readb(TODO: Binary); * file: sst28sf040.c line 43 has assignment to unnecessarily volatile variable: tmp = readb(TODO: Binary); * file: sst28sf040.c line 42 has assignment to unnecessarily volatile variable: tmp = readb(TODO: Binary); * file: sst28sf040.c line 41 has assignment to unnecessarily volatile variable: tmp = readb(TODO: Binary); * file: sst28sf040.c line 40 has assignment to unnecessarily volatile variable: tmp = readb(TODO: Binary); * file: sst28sf040.c line 39 has assignment to unnecessarily volatile variable: tmp = readb(TODO: Binary); * file: sst28sf040.c line 38 has assignment to unnecessarily volatile variable: tmp = readb(TODO: Binary); * file: sst28sf040.c line 58 has assignment to unnecessarily volatile variable: tmp = readb(TODO: Binary); * file: sst28sf040.c line 57 has assignment to unnecessarily volatile variable: tmp = readb(TODO: Binary); * file: sst28sf040.c line 56 has assignment to unnecessarily volatile variable: tmp = readb(TODO: Binary); * file: sst28sf040.c line 55 has assignment to unnecessarily volatile variable: tmp = readb(TODO: Binary); * file: sst28sf040.c line 54 has assignment to unnecessarily volatile variable: tmp = readb(TODO: Binary); * file: sst28sf040.c line 53 has assignment to unnecessarily volatile variable: tmp = readb(TODO: Binary); * file: sst28sf040.c line 52 has assignment to unnecessarily volatile variable: tmp = readb(TODO: Binary);
The following semantic patch uses the spatch builtin match printing functionality by prepending a "*" to the line with the pattern: @@ expression b; typedef uint8_t; volatile uint8_t a; @@ * a = readb(b);
Result is: HANDLING: sst28sf040.c diff = --- sst28sf040.c 2009-03-06 01:04:49.000000000 +0100 @@ -35,13 +35,6 @@ static __inline__ void protect_28sf040(v /* ask compiler not to optimize this */ volatile uint8_t tmp;
- tmp = readb(bios + 0x1823); - tmp = readb(bios + 0x1820); - tmp = readb(bios + 0x1822); - tmp = readb(bios + 0x0418); - tmp = readb(bios + 0x041B); - tmp = readb(bios + 0x0419); - tmp = readb(bios + 0x040A); }
static __inline__ void unprotect_28sf040(volatile uint8_t *bios) @@ -49,13 +42,6 @@ static __inline__ void unprotect_28sf040 /* ask compiler not to optimize this */ volatile uint8_t tmp;
- tmp = readb(bios + 0x1823); - tmp = readb(bios + 0x1820); - tmp = readb(bios + 0x1822); - tmp = readb(bios + 0x0418); - tmp = readb(bios + 0x041B); - tmp = readb(bios + 0x0419); - tmp = readb(bios + 0x041A); }
static __inline__ int erase_sector_28sf040(volatile uint8_t *bios,
It's arguably a bit easier to read if you get used to the leading "-" for matching lines.
This patch was enabled by Coccinelle: http://www.emn.fr/x-info/coccinelle/
Signed-off-by: Carl-Daniel Hailfinger c-d.hailfinger.devel.2006@gmx.net Acked-by: Joseph Smith joe@settoplinux.org
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