Module Name: src
Committed By: rillig
Date: Mon Dec 21 00:11:29 UTC 2020
Modified Files:
src/usr.bin/make: var.c
Log Message:
make(1): clean up memory management for expanding variable expressions
Previously, memory management had been split among several variables.
The general idea was very simple though. The current value of the
expression needs to be kept in memory, and each modifier either keeps
that value or replaces it with its own newly allocated result, or
var_Error or varUndefined.
Using MFStr, it does not matter anymore that var_Error and varUndefined
are statically allocated since these are assigned using MFStr_InitRefer.
The complexity of the implementation is now closer to the actual
complexity. Most probably the code can be simplified even more.
To generate a diff of this commit:
cvs rdiff -u -r1.756 -r1.757 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/var.c
diff -u src/usr.bin/make/var.c:1.756 src/usr.bin/make/var.c:1.757
--- src/usr.bin/make/var.c:1.756 Sun Dec 20 23:27:37 2020
+++ src/usr.bin/make/var.c Mon Dec 21 00:11:29 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: var.c,v 1.756 2020/12/20 23:27:37 rillig Exp $ */
+/* $NetBSD: var.c,v 1.757 2020/12/21 00:11:29 rillig Exp $ */
/*
* Copyright (c) 1988, 1989, 1990, 1993
@@ -131,7 +131,7 @@
#include "metachar.h"
/* "@(#)var.c 8.3 (Berkeley) 3/19/94" */
-MAKE_RCSID("$NetBSD: var.c,v 1.756 2020/12/20 23:27:37 rillig Exp $");
+MAKE_RCSID("$NetBSD: var.c,v 1.757 2020/12/21 00:11:29 rillig Exp $");
typedef enum VarFlags {
VAR_NONE = 0,
@@ -3420,8 +3420,8 @@ ApplyModifier(const char **pp, char *val
}
}
-static char *ApplyModifiers(const char **, char *, char, char, Var *,
- VarExprFlags *, GNode *, VarEvalFlags, void **);
+static MFStr ApplyModifiers(const char **, MFStr, char, char, Var *,
+ VarExprFlags *, GNode *, VarEvalFlags);
typedef enum ApplyModifiersIndirectResult {
/* The indirect modifiers have been applied successfully. */
@@ -3450,7 +3450,7 @@ typedef enum ApplyModifiersIndirectResul
*/
static ApplyModifiersIndirectResult
ApplyModifiersIndirect(ApplyModifiersState *st, const char **pp,
- char **inout_val, void **inout_freeIt)
+ MFStr *inout_value)
{
const char *p = *pp;
FStr mods;
@@ -3468,10 +3468,10 @@ ApplyModifiersIndirect(ApplyModifiersSta
if (mods.str[0] != '\0') {
const char *modsp = mods.str;
- *inout_val = ApplyModifiers(&modsp, *inout_val, '\0', '\0',
- st->var, &st->exprFlags, st->ctxt, st->eflags,
- inout_freeIt);
- if (*inout_val == var_Error || *inout_val == varUndefined ||
+ MFStr newVal = ApplyModifiers(&modsp, *inout_value, '\0', '\0',
+ st->var, &st->exprFlags, st->ctxt, st->eflags);
+ *inout_value = newVal;
+ if (newVal.str == var_Error || newVal.str == varUndefined ||
*modsp != '\0') {
FStr_Done(&mods);
*pp = p;
@@ -3496,11 +3496,11 @@ ApplyModifiersIndirect(ApplyModifiersSta
static ApplyModifierResult
ApplySingleModifier(ApplyModifiersState *st, const char *mod, char endc,
- const char **pp, char *val, char **out_val,
- void **inout_freeIt)
+ const char **pp, MFStr *inout_value)
{
ApplyModifierResult res;
const char *p = *pp;
+ char *const val = inout_value->str;
if (DEBUG(VAR))
LogBeforeApply(st, mod, endc, val);
@@ -3527,7 +3527,6 @@ ApplySingleModifier(ApplyModifiersState
st->newVal = MFStr_InitRefer(var_Error);
}
if (res == AMR_CLEANUP || res == AMR_BAD) {
- *out_val = val;
*pp = p;
return res;
}
@@ -3536,20 +3535,14 @@ ApplySingleModifier(ApplyModifiersState
LogAfterApply(st, p, mod);
if (st->newVal.str != val) {
- if (*inout_freeIt != NULL) {
- assert(*inout_freeIt == val);
- free(*inout_freeIt);
- *inout_freeIt = NULL;
- }
- val = st->newVal.str;
- if (val != var_Error && val != varUndefined)
- *inout_freeIt = val;
+ MFStr_Done(inout_value);
+ *inout_value = st->newVal;
}
if (*p == '\0' && st->endc != '\0') {
Error(
"Unclosed variable specification (expecting '%c') "
"for \"%s\" (value \"%s\") modifier %c",
- st->endc, st->var->name.str, val, *mod);
+ st->endc, st->var->name.str, inout_value->str, *mod);
} else if (*p == ':') {
p++;
} else if (opts.lint && *p != '\0' && *p != endc) {
@@ -3562,22 +3555,20 @@ ApplySingleModifier(ApplyModifiersState
*/
}
*pp = p;
- *out_val = val;
return AMR_OK;
}
/* Apply any modifiers (such as :Mpattern or :@var@loop@ or :Q or ::=value). */
-static char *
+static MFStr
ApplyModifiers(
const char **pp, /* the parsing position, updated upon return */
- char *val, /* the current value of the expression */
+ MFStr value, /* the current value of the expression */
char startc, /* '(' or '{', or '\0' for indirect modifiers */
char endc, /* ')' or '}', or '\0' for indirect modifiers */
Var *v,
VarExprFlags *exprFlags,
GNode *ctxt, /* for looking up and modifying variables */
- VarEvalFlags eflags,
- void **inout_freeIt /* free this after using the return value */
+ VarEvalFlags eflags
)
{
ApplyModifiersState st = {
@@ -3592,7 +3583,7 @@ ApplyModifiers(
assert(startc == '(' || startc == '{' || startc == '\0');
assert(endc == ')' || endc == '}' || endc == '\0');
- assert(val != NULL);
+ assert(value.str != NULL);
p = *pp;
@@ -3608,8 +3599,7 @@ ApplyModifiers(
if (*p == '$') {
ApplyModifiersIndirectResult amir;
- amir = ApplyModifiersIndirect(&st, &p, &val,
- inout_freeIt);
+ amir = ApplyModifiersIndirect(&st, &p, &value);
if (amir == AMIR_CONTINUE)
continue;
if (amir == AMIR_OUT)
@@ -3620,8 +3610,7 @@ ApplyModifiers(
st.newVal = MFStr_InitRefer(var_Error);
mod = p;
- res = ApplySingleModifier(&st, mod, endc, &p, val, &val,
- inout_freeIt);
+ res = ApplySingleModifier(&st, mod, endc, &p, &value);
if (res == AMR_CLEANUP)
goto cleanup;
if (res == AMR_BAD)
@@ -3629,9 +3618,9 @@ ApplyModifiers(
}
*pp = p;
- assert(val != NULL); /* Use var_Error or varUndefined instead. */
+ assert(value.str != NULL); /* Use var_Error or varUndefined instead. */
*exprFlags = st.exprFlags;
- return val;
+ return value;
bad_modifier:
/* XXX: The modifier end is only guessed. */
@@ -3640,10 +3629,9 @@ bad_modifier:
cleanup:
*pp = p;
- free(*inout_freeIt);
- *inout_freeIt = NULL;
+ MFStr_Done(&value);
*exprFlags = st.exprFlags;
- return var_Error;
+ return MFStr_InitRefer(var_Error);
}
/* Only four of the local variables are treated specially as they are the
@@ -4118,24 +4106,17 @@ Var_Parse(const char **pp, GNode *ctxt,
}
if (haveModifier || extramodifiers != NULL) {
- void *extraFree;
-
- extraFree = NULL;
if (extramodifiers != NULL) {
const char *em = extramodifiers;
- value.str = ApplyModifiers(&em, value.str, '\0', '\0',
- v, &exprFlags, ctxt, eflags, &extraFree);
+ value = ApplyModifiers(&em, value, '\0', '\0',
+ v, &exprFlags, ctxt, eflags);
}
if (haveModifier) {
- /* Skip initial colon. */
- p++;
+ p++; /* Skip initial colon. */
- value.str = ApplyModifiers(&p, value.str, startc, endc,
- v, &exprFlags, ctxt, eflags, &value.freeIt);
- free(extraFree);
- } else {
- value.freeIt = extraFree;
+ value = ApplyModifiers(&p, value, startc, endc,
+ v, &exprFlags, ctxt, eflags);
}
}
