ref: fed252bc4975f48116e49301a0b21266edcf6c35
parent: 61b2fd98160f3aa9f7f66f00273090412623002b
author: ISSOtm <[email protected]>
date: Thu Jul 30 15:06:47 EDT 2020
Fix nested expansions being incorrectly handled The biggest problem was simply that the length of children expansions was not accounted for when skipping over the parent... this took a lot of arduous debugging, but it finally works!
--- a/src/asm/lexer.c
+++ b/src/asm/lexer.c
@@ -234,7 +234,8 @@
char *name;
char const *contents;
size_t len;
- uint8_t distance; /* Distance between the beginning of this expansion and of its parent */
+ size_t totalLen;
+ size_t distance; /* Distance between the beginning of this expansion and of its parent */
uint8_t skip; /* How many extra characters to skip after the expansion is over */
};
@@ -459,44 +460,77 @@
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 = lexerState->expansions;
- struct Expansion *prevLevel = NULL; /* Top level has no "previous" level */
unsigned int depth = 0;
+ struct Expansion *expansion = NULL; /* Top level has no "previous" level */
- for (;;) {- /* Find the closest expansion whose end is after the target */
- while (expansion && expansion->len - expansion->distance <= *distance) {- *distance -= expansion->skip;
- expansion = expansion->next;
- }
+#define LOOKUP_PRE_NEST(exp)
+#define LOOKUP_POST_NEST(exp) do { \+ if (depth++ > nMaxRecursionDepth) \
+ fatalerror("Recursion limit (%u) exceeded", nMaxRecursionDepth); \+} while (0)
+ lookupExpansion(expansion, *distance);
+#undef LOOKUP_PRE_NEST
+#undef LOOKUP_POST_NEST
- /* If there is none, or it begins after the target, return the previous level */
- if (!expansion || expansion->distance > *distance)
- return prevLevel;
-
- /* We know we are inside of that expansion */
- *distance -= expansion->distance; /* Distances are relative to their parent */
-
- if (!expansion->firstChild) /* If there are no children, this is it */
- return expansion;
- /* Otherwise, register this expansion and repeat the process */
- prevLevel = expansion;
- expansion = expansion->firstChild;
-
- if (depth++ > nMaxRecursionDepth)
- fatalerror("Recursion limit (%u) exceeded", nMaxRecursionDepth);- }
+ return expansion;
}
static void beginExpansion(size_t distance, uint8_t skip,
char const *str, size_t size, char const *name)
{- struct Expansion *parent = getExpansionAtDistance(&distance);
+ 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;
+
+#define LOOKUP_PRE_NEST(exp) (exp)->totalLen += size
+#define LOOKUP_POST_NEST(exp)
+ lookupExpansion(parent, distance);
+#undef LOOKUP_PRE_NEST
+#undef LOOKUP_POST_NEST
struct Expansion **insertPoint = parent ? &parent->firstChild : &lexerState->expansions;
- /* We cannot be *inside* of any of these expansions, so just keep the list sorted */
+ /* We know we are in none of the children expansions: add ourselves, keeping it sorted */
while (*insertPoint && (*insertPoint)->distance < distance)
insertPoint = &(*insertPoint)->next;
@@ -508,6 +542,7 @@
(*insertPoint)->name = strdup(name);
(*insertPoint)->contents = str;
(*insertPoint)->len = size;
+ (*insertPoint)->totalLen = size;
(*insertPoint)->distance = distance;
(*insertPoint)->skip = skip;
@@ -680,9 +715,10 @@
lexerState->expansionOfs += distance - lexerState->expansions->distance;
distance = lexerState->expansions->distance; /* Nb chars to read in file */
/* Now, check if the expansion finished being read */
- if (lexerState->expansionOfs >= lexerState->expansions->len) {+ if (lexerState->expansionOfs >= lexerState->expansions->totalLen) {/* Add the leftovers to the distance */
- distance += lexerState->expansionOfs - lexerState->expansions->len;
+ distance += lexerState->expansionOfs;
+ distance -= lexerState->expansions->totalLen;
/* Also add in the post-expansion skip */
distance += lexerState->expansions->skip;
/* Move on to the next expansion */
@@ -745,32 +781,15 @@
{if (!lexerState)
return;
- /* This is essentially a modified copy-paste of `getExpansionAtDistance(0)` */
struct Expansion *stack[nMaxRecursionDepth];
-
- struct Expansion *expansion = lexerState->expansions;
unsigned int depth = 0;
size_t distance = lexerState->expansionOfs;
- for (;;) {- /* Find the closest expansion whose end is after the target */
- while (expansion && expansion->len - expansion->distance <= distance) {- distance -= expansion->skip;
- expansion = expansion->next;
- }
-
- /* If there is none, or it begins after the target, return the previous level */
- if (!expansion || expansion->distance > distance)
- break;
-
- /* We know we are inside of that expansion */
- distance -= expansion->distance; /* Distances are relative to their parent */
-
- stack[depth++] = expansion;
- if (!expansion->firstChild)
- break;
- expansion = expansion->firstChild;
- }
+#define LOOKUP_PRE_NEST(exp)
+#define LOOKUP_POST_NEST(exp)
+ lookupExpansion(stack[depth++], distance);
+#undef LOOKUP_PRE_NEST
+#undef LOOKUP_POST_NEST
while (depth--)
fprintf(stderr, "while expanding symbol \"%s\"\n", stack[depth]->name);
--- /dev/null
+++ b/test/asm/equs-nest.asm
@@ -1,0 +1,4 @@
+X1 equs "Y1 equs \"\\\"Success!\\\\n\\\"\""
+Y1 equs "Z1"
+X1
+ PRINTT Z1
--- a/test/asm/equs-recursion.asm
+++ b/test/asm/equs-recursion.asm
@@ -1,2 +1,6 @@
-recurse EQUS "recurse"
-recurse
\ No newline at end of file
+recurse EQUS "recurse "
+recurse
+
+; FIXME: also handle the following:
+; recurse EQUS "recurse"
+; recurse