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view dmd2/lstring.c @ 1275:bedf0bfb8fdb
Implement first D-specific optimization pass: -simplify-drtcalls.
It uses the machinery of the standard -simplify-libcalls pass, but optimizes
calls to the D runtime instead of calls to C libraries.
At the moment, these optimizations are implemented by this pass:
- Avoid the runtime call for `arr.length = newlen` if it can determine that
the new length isn't longer than the old one.
- Ditto for `cast(T[]) arr` if it will clearly always succeed.
(e.g. if the length of the original array is zero, or if the old element
size is a multiple of the new element size)
author | Frits van Bommel <fvbommel wxs.nl> |
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date | Tue, 28 Apr 2009 21:58:06 +0200 |
parents | 356e65836fb5 |
children |
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// lstring.c // Copyright (c) 1999-2002 by Digital Mars // All Rights Reserved // written by Walter Bright // www.digitalmars.com // License for redistribution is by either the Artistic License // in artistic.txt, or the GNU General Public License in gnu.txt. // See the included readme.txt for details. #include <stdlib.h> #include "dchar.h" #include "mem.h" #include "lstring.h" #ifdef _MSC_VER // prevent compiler internal crash Lstring Lstring::zero; #else Lstring Lstring::zero = LSTRING_EMPTY(); #endif Lstring *Lstring::ctor(const dchar *p, unsigned length) { Lstring *s; s = alloc(length); memcpy(s->string, p, length * sizeof(dchar)); return s; } Lstring *Lstring::alloc(unsigned length) { Lstring *s; s = (Lstring *)mem.malloc(size(length)); s->length = length; s->string[length] = 0; return s; } Lstring *Lstring::append(const Lstring *s) { Lstring *t; if (!s->length) return this; t = alloc(length + s->length); memcpy(t->string, string, length * sizeof(dchar)); memcpy(t->string + length, s->string, s->length * sizeof(dchar)); return t; } Lstring *Lstring::substring(int start, int end) { Lstring *t; if (start == end) return &zero; t = alloc(end - start); memcpy(t->string, string + start, (end - start) * sizeof(dchar)); return t; }