ref: 7fc8a65d0a428f8ee6978619ad4bd5b0acb64749
parent: c278a361dadead172322198c8e325e8444b8b047
author: Rangi <remy.oukaour+rangi42@gmail.com>
date: Thu Apr 1 11:54:56 EDT 2021
Refactor the lexer to not use the `lookupExpansion` X macro This macro was only used twice, in `beginExpansion` and `lexer_DumpStringExpansions`, with `getExpansionAtDistance` already containing an inlined and slightly modified version of `lookupExpansion` (retaining the `LOOKUP_PRE_NEST` and `LOOKUP_POST_NEST` macros, but with both of them doing nothing). Not using an X macro here makes the actual control flow in both places more obvious, and I think the repeated code is acceptable for the same reasons as the similar-but-distinct implementations of `readString`, `appendStringLiteral`, `yylex_NORMAL`, and `yylex_RAW`.
--- a/src/asm/lexer.c
+++ b/src/asm/lexer.c
@@ -671,54 +671,11 @@
fatalerror("realloc error while resizing capture buffer: %s\n", strerror(errno));}
-/*
- * The multiple evaluations of `retvar` causing side effects is INTENTIONAL, and
- * required for example by `lexer_dumpStringExpansions`. It is however only
- * evaluated once per level, and only then.
- *
- * This uses the concept of "X macros": you must #define LOOKUP_PRE_NEST and
- * LOOKUP_POST_NEST before invoking this (and #undef them right after), and
- * those macros will be expanded at the corresponding points in the loop.
- * This is necessary because there are at least 3 places which need to iterate
- * through iterations while performing custom actions
- */
-#define lookupExpansion(retvar, dist) do { \- struct Expansion *exp = lexerState->expansions; \
- \
- for (;;) { \- /* Find the closest expansion whose end is after the target */ \
- while (exp && exp->totalLen + exp->distance <= (dist)) { \- (dist) -= exp->totalLen + exp->skip; \
- exp = exp->next; \
- } \
- \
- /* If there is none, or it begins after the target, return the previous level */ \
- if (!exp || exp->distance > (dist)) \
- break; \
- \
- /* We know we are inside of that expansion */ \
- (dist) -= exp->distance; /* Distances are relative to their parent */ \
- \
- /* Otherwise, register this expansion and repeat the process */ \
- LOOKUP_PRE_NEST(exp); \
- (retvar) = exp; \
- if (!exp->firstChild) /* If there are no children, this is it */ \
- break; \
- exp = exp->firstChild; \
- \
- LOOKUP_POST_NEST(exp); \
- } \
-} while (0)
-
static struct Expansion *getExpansionAtDistance(size_t *distance)
{struct Expansion *expansion = NULL; /* Top level has no "previous" level */
-#define LOOKUP_PRE_NEST(exp)
-#define LOOKUP_POST_NEST(exp)
- struct Expansion *exp = lexerState->expansions;
-
- for (;;) {+ for (struct Expansion *exp = lexerState->expansions; exp; exp = exp->firstChild) {/* Find the closest expansion whose end is after the target */
while (exp && exp->totalLen + exp->distance <= *distance) {*distance -= exp->totalLen - exp->skip;
@@ -725,7 +682,7 @@
exp = exp->next;
}
- /* If there is none, or it begins after the target, return the previous level */
+ /* If there is none, or it begins after the target, stop at previous level */
if (!exp || exp->distance > *distance)
break;
@@ -733,16 +690,8 @@
*distance -= exp->distance; /* Distances are relative to their parent */
/* Otherwise, register this expansion and repeat the process */
- LOOKUP_PRE_NEST(exp);
expansion = exp;
- if (!exp->firstChild) /* If there are no children, this is it */
- break;
- exp = exp->firstChild;
-
- LOOKUP_POST_NEST(exp);
}
-#undef LOOKUP_PRE_NEST
-#undef LOOKUP_POST_NEST
return expansion;
}
@@ -757,21 +706,34 @@
return;
distance += lexerState->expansionOfs; /* Distance argument is relative to read offset! */
+
/* Increase the total length of all parents, and return the topmost one */
struct Expansion *parent = NULL;
unsigned int depth = 0;
-#define LOOKUP_PRE_NEST(exp) do { \- assert((exp)->totalLen <= SIZE_MAX - (size - skip)); \
- (exp)->totalLen += size - skip; \
-} while (0)
-#define LOOKUP_POST_NEST(exp) do { \- if (name && ++depth >= nMaxRecursionDepth) \
- fatalerror("Recursion limit (%zu) exceeded\n", nMaxRecursionDepth); \-} while (0)
- lookupExpansion(parent, distance);
-#undef LOOKUP_PRE_NEST
-#undef LOOKUP_POST_NEST
+ for (struct Expansion *exp = lexerState->expansions; exp; exp = exp->firstChild) {+ /* Find the closest expansion whose end is after the target */
+ while (exp && exp->totalLen + exp->distance <= distance) {+ distance -= exp->totalLen + exp->skip;
+ exp = exp->next;
+ }
+
+ /* If there is none, or it begins after the target, stop at the previous level */
+ if (!exp || exp->distance > distance)
+ break;
+
+ /* We know we are inside of that expansion */
+ distance -= exp->distance; /* Distances are relative to their parent */
+
+ /* Otherwise, register this expansion and repeat the process */
+ assert(exp->totalLen <= SIZE_MAX - (size - skip));
+ exp->totalLen += size - skip;
+ parent = exp;
+
+ if (name && depth++ >= nMaxRecursionDepth)
+ fatalerror("Recursion limit (%zu) exceeded\n", nMaxRecursionDepth);+ }
+
struct Expansion **insertPoint = parent ? &parent->firstChild : &lexerState->expansions;
/* We know we are in none of the children expansions: add ourselves, keeping it sorted */
@@ -1069,7 +1031,6 @@
if (!lexerState)
return;
struct Expansion **stack = malloc(sizeof(*stack) * (nMaxRecursionDepth + 1));
- struct Expansion *expansion; /* Temp var for `lookupExpansion` */
unsigned int depth = 0;
size_t distance = lexerState->expansionOfs;
@@ -1076,16 +1037,24 @@
if (!stack)
fatalerror("Failed to alloc string expansion stack: %s\n", strerror(errno));-#define LOOKUP_PRE_NEST(exp) do { \- /* Only register EQUS expansions, not string args */ \
- if ((exp)->name) \
- stack[depth++] = (exp); \
-} while (0)
-#define LOOKUP_POST_NEST(exp)
- lookupExpansion(expansion, distance);
- (void)expansion;
-#undef LOOKUP_PRE_NEST
-#undef LOOKUP_POST_NEST
+ for (struct Expansion *exp = lexerState->expansions; exp; exp = exp->firstChild) {+ /* Find the closest expansion whose end is after the target */
+ while (exp && exp->totalLen + exp->distance <= distance) {+ distance -= exp->totalLen + exp->skip;
+ exp = exp->next;
+ }
+
+ /* If there is none, or it begins after the target, stop at the previous level */
+ if (!exp || exp->distance > distance)
+ break;
+
+ /* We know we are inside of that expansion */
+ distance -= exp->distance; /* Distances are relative to their parent */
+
+ /* Only register EQUS expansions, not string args */
+ if (exp->name)
+ stack[depth++] = exp;
+ }
while (depth--)
fprintf(stderr, "while expanding symbol \"%s\"\n", stack[depth]->name);