Module Name: src
Committed By: rillig
Date: Mon Apr 12 18:48:00 UTC 2021
Modified Files:
src/usr.bin/make: str.h var.c
Log Message:
make: reduce memory allocation and strlen calls in modifier ':from=to'
Previously, SysVMatch was quite verbose and felt like hand-optimized
assembler code, which made it difficult to discover the underlying idea
of the code.
All this code was replaced with two simple calls to Substring_HasPrefix
and Substring_HasSuffix. Now that the operands of that modifier are no
longer passed as C strings, there is no need to collect all information
in a single scan through the word and the pattern.
It was not necessary to call Var_Subst unconditionally. Calling it only
when the string contains a '$' saves another memory allocation and two
string copies (because of the Buf_DoneDataCompact).
No functional change.
To generate a diff of this commit:
cvs rdiff -u -r1.5 -r1.6 src/usr.bin/make/str.h
cvs rdiff -u -r1.924 -r1.925 src/usr.bin/make/var.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/usr.bin/make/str.h
diff -u src/usr.bin/make/str.h:1.5 src/usr.bin/make/str.h:1.6
--- src/usr.bin/make/str.h:1.5 Sun Apr 11 22:53:45 2021
+++ src/usr.bin/make/str.h Mon Apr 12 18:48:00 2021
@@ -1,4 +1,4 @@
-/* $NetBSD: str.h,v 1.5 2021/04/11 22:53:45 rillig Exp $ */
+/* $NetBSD: str.h,v 1.6 2021/04/12 18:48:00 rillig Exp $ */
/*
Copyright (c) 2021 Roland Illig <ril...@netbsd.org>
@@ -190,6 +190,21 @@ Substring_Sub(Substring sub, size_t star
return Substring_Init(sub.start + start, sub.start + end);
}
+MAKE_INLINE bool
+Substring_HasPrefix(Substring sub, Substring prefix)
+{
+ return Substring_Length(sub) >= Substring_Length(prefix) &&
+ memcmp(sub.start, prefix.start, Substring_Length(prefix)) == 0;
+}
+
+MAKE_INLINE bool
+Substring_HasSuffix(Substring sub, Substring suffix)
+{
+ size_t suffixLen = Substring_Length(suffix);
+ return Substring_Length(sub) >= suffixLen &&
+ memcmp(sub.end - suffixLen, suffix.start, suffixLen) == 0;
+}
+
MAKE_INLINE FStr
Substring_Str(Substring sub)
{
@@ -197,6 +212,17 @@ Substring_Str(Substring sub)
}
MAKE_INLINE const char *
+Substring_SkipFirst(Substring sub, char ch)
+{
+ const char *p;
+
+ for (p = sub.start; p != sub.end; p++)
+ if (*p == ch)
+ return p + 1;
+ return sub.start;
+}
+
+MAKE_INLINE const char *
Substring_LastIndex(Substring sub, char ch)
{
const char *p;
Index: src/usr.bin/make/var.c
diff -u src/usr.bin/make/var.c:1.924 src/usr.bin/make/var.c:1.925
--- src/usr.bin/make/var.c:1.924 Mon Apr 12 13:28:35 2021
+++ src/usr.bin/make/var.c Mon Apr 12 18:48:00 2021
@@ -1,4 +1,4 @@
-/* $NetBSD: var.c,v 1.924 2021/04/12 13:28:35 rillig Exp $ */
+/* $NetBSD: var.c,v 1.925 2021/04/12 18:48:00 rillig Exp $ */
/*
* Copyright (c) 1988, 1989, 1990, 1993
@@ -140,7 +140,7 @@
#include "metachar.h"
/* "@(#)var.c 8.3 (Berkeley) 3/19/94" */
-MAKE_RCSID("$NetBSD: var.c,v 1.924 2021/04/12 13:28:35 rillig Exp $");
+MAKE_RCSID("$NetBSD: var.c,v 1.925 2021/04/12 18:48:00 rillig Exp $");
/*
* Variables are defined using one of the VAR=value assignments. Their
@@ -1441,69 +1441,11 @@ ModifyWord_NoMatch(Substring word, SepBu
}
#ifdef SYSVVARSUB
-
-/*
- * Check word against pattern for a match (% is a wildcard).
- *
- * Input:
- * word Word to examine
- * pattern Pattern to examine against
- *
- * Results:
- * Returns the start of the match, or NULL.
- * out_match_len returns the length of the match, if any.
- * out_hasPercent returns whether the pattern contains a percent.
- */
-/* TODO: migrate to using Substring */
-static const char *
-SysVMatch(const char *word, const char *pattern,
- size_t *out_match_len, bool *out_hasPercent)
-{
- const char *p = pattern;
- const char *w = word;
- const char *percent;
- size_t w_len;
- size_t p_len;
- const char *w_tail;
-
- *out_hasPercent = false;
- percent = strchr(p, '%');
- if (percent != NULL) { /* ${VAR:...%...=...} */
- *out_hasPercent = true;
- if (w[0] == '\0')
- return NULL; /* empty word does not match pattern */
-
- /* check that the prefix matches */
- for (; p != percent && *w != '\0' && *w == *p; w++, p++)
- continue;
- if (p != percent)
- return NULL; /* No match */
-
- p++; /* Skip the percent */
- if (*p == '\0') {
- /* No more pattern, return the rest of the string */
- *out_match_len = strlen(w);
- return w;
- }
- }
-
- /* Test whether the tail matches */
- w_len = strlen(w);
- p_len = strlen(p);
- if (w_len < p_len)
- return NULL;
-
- w_tail = w + w_len - p_len;
- if (memcmp(p, w_tail, p_len) != 0)
- return NULL;
-
- *out_match_len = (size_t)(w_tail - w);
- return w;
-}
-
struct ModifyWord_SYSVSubstArgs {
GNode *scope;
- const char *lhs;
+ Substring lhsPrefix;
+ bool lhsPercent;
+ Substring lhsSuffix;
const char *rhs;
};
@@ -1512,43 +1454,40 @@ static void
ModifyWord_SYSVSubst(Substring word, SepBuf *buf, void *data)
{
const struct ModifyWord_SYSVSubstArgs *args = data;
- char *rhs_expanded;
- const char *rhs;
+ FStr rhs;
+ char *rhsExp;
const char *percent;
- size_t match_len;
- bool lhsPercent;
- const char *match;
- assert(word.end[0] == '\0'); /* assume null-terminated word */
- match = SysVMatch(word.start, args->lhs, &match_len, &lhsPercent);
- if (match == NULL) {
- SepBuf_AddSubstring(buf, word);
+ if (Substring_IsEmpty(word))
return;
- }
- /*
- * Append rhs to the buffer, substituting the first '%' with the
- * match, but only if the lhs had a '%' as well.
- */
-
- (void)Var_Subst(args->rhs, args->scope, VARE_WANTRES, &rhs_expanded);
- /* TODO: handle errors */
+ if (!Substring_HasPrefix(word, args->lhsPrefix))
+ goto no_match;
+ if (!Substring_HasSuffix(word, args->lhsSuffix))
+ goto no_match;
+
+ rhs = FStr_InitRefer(args->rhs);
+ if (strchr(rhs.str, '$') != NULL) {
+ (void)Var_Subst(args->rhs, args->scope, VARE_WANTRES, &rhsExp);
+ /* TODO: handle errors */
+ rhs = FStr_InitOwn(rhsExp);
+ }
- rhs = rhs_expanded;
- percent = strchr(rhs, '%');
+ percent = args->lhsPercent ? strchr(rhs.str, '%') : NULL;
- if (percent != NULL && lhsPercent) {
- /* Copy the prefix of the replacement pattern */
- SepBuf_AddBytesBetween(buf, rhs, percent);
- rhs = percent + 1;
- }
- if (percent != NULL || !lhsPercent)
- SepBuf_AddBytes(buf, match, match_len);
+ if (percent != NULL)
+ SepBuf_AddBytesBetween(buf, rhs.str, percent);
+ if (percent != NULL || !args->lhsPercent)
+ SepBuf_AddBytesBetween(buf,
+ word.start + Substring_Length(args->lhsPrefix),
+ word.end - Substring_Length(args->lhsSuffix));
+ SepBuf_AddStr(buf, percent != NULL ? percent + 1 : rhs.str);
- /* Append the suffix of the replacement pattern */
- SepBuf_AddStr(buf, rhs);
+ FStr_Done(&rhs);
+ return;
- free(rhs_expanded);
+no_match:
+ SepBuf_AddSubstring(buf, word);
}
#endif
@@ -3646,8 +3585,11 @@ ApplyModifier_SysV(const char **pp, ModC
{
Expr *expr = ch->expr;
VarParseResult res;
- LazyBuf buf;
- FStr lhs, rhs;
+ LazyBuf lhsBuf, rhsBuf;
+ FStr rhs;
+ struct ModifyWord_SYSVSubstArgs args;
+ Substring lhs;
+ const char *lhsSuffix;
const char *mod = *pp;
bool eqFound = false;
@@ -3672,33 +3614,38 @@ ApplyModifier_SysV(const char **pp, ModC
if (*p != ch->endc || !eqFound)
return AMR_UNKNOWN;
- res = ParseModifierPart(pp, '=', expr->emode, ch, &buf);
+ res = ParseModifierPart(pp, '=', expr->emode, ch, &lhsBuf);
if (res != VPR_OK)
return AMR_CLEANUP;
- lhs = LazyBuf_DoneGet(&buf);
/* The SysV modifier lasts until the end of the variable expression. */
- res = ParseModifierPart(pp, ch->endc, expr->emode, ch, &buf);
+ res = ParseModifierPart(pp, ch->endc, expr->emode, ch, &rhsBuf);
if (res != VPR_OK) {
- FStr_Done(&lhs);
+ LazyBuf_Done(&lhsBuf);
return AMR_CLEANUP;
}
- rhs = LazyBuf_DoneGet(&buf);
+ rhs = LazyBuf_DoneGet(&rhsBuf);
(*pp)--; /* Go back to the ch->endc. */
- if (lhs.str[0] == '\0' && expr->value.str[0] == '\0') {
- /* Do not turn an empty expression into non-empty. */
- } else {
- struct ModifyWord_SYSVSubstArgs args;
+ /* Do not turn an empty expression into non-empty. */
+ if (lhsBuf.len == 0 && expr->value.str[0] == '\0')
+ goto done;
- args.scope = expr->scope;
- args.lhs = lhs.str;
- args.rhs = rhs.str;
- ModifyWords(ch, ModifyWord_SYSVSubst, &args, ch->oneBigWord);
- }
- FStr_Done(&lhs);
- FStr_Done(&rhs);
+ lhs = LazyBuf_Get(&lhsBuf);
+ lhsSuffix = Substring_SkipFirst(lhs, '%');
+
+ args.scope = expr->scope;
+ args.lhsPrefix = Substring_Init(lhs.start,
+ lhsSuffix != lhs.start ? lhsSuffix - 1 : lhs.start);
+ args.lhsPercent = lhsSuffix != lhs.start;
+ args.lhsSuffix = Substring_Init(lhsSuffix, lhs.end);
+ args.rhs = rhs.str;
+
+ ModifyWords(ch, ModifyWord_SYSVSubst, &args, ch->oneBigWord);
+
+done:
+ LazyBuf_Done(&lhsBuf);
return AMR_OK;
}
#endif
