Re-implement smart linking

Long-broken feature, fell into disrepair, got removed...
Now it's back! Though, it needs testing.
Fixes gbdev#82

Author: ISSOtm

include/hashmap.h

@@ -47,9 +47,9 @@ bool hash_ReplaceElement(HashMap const map, char const *key, void *element);
  * Removes an element from a hashmap.
  * @param map The HashMap to remove the element from
  * @param key The key to search the element with
- * @return True if the element was found and removed
+ * @return The element removed, or NULL if none was found
  */
-bool hash_RemoveElement(HashMap map, char const *key);
+void *hash_RemoveElement(HashMap map, char const *key);
 
 /**
  * Finds an element in a hashmap.
@@ -74,6 +74,6 @@ void hash_ForEach(HashMap const map, void (*func)(void *, void *), void *arg);
  * This does not `free` the data structure itself!
  * @param map The map to empty
  */
-void hash_EmptyMap(HashMap map);
+void hash_EmptyMap(HashMap map, void (*callback)(void *));
 
 #endif /* RGBDS_LINK_HASHMAP_H */

include/link/object.h

@@ -23,6 +23,11 @@ void obj_ReadFile(char const *fileName, unsigned int i);
  */
 void obj_DoSanityChecks(void);
 
+/**
+ * @return The first assertion in the linked list of all assertions
+ */
+struct Assertion const *obj_GetFirstAssertion(void);
+
 /**
  * Evaluate all assertions
  */

include/link/patch.h

@@ -17,6 +17,8 @@
 
 #include "linkdefs.h"
 
+struct Symbol;
+
 struct Assertion {
 	struct Patch patch;
 	// enum AssertionType type; The `patch`'s field is instead re-used
@@ -32,6 +34,7 @@ struct Assertion {
 
 /**
  * Checks all assertions
+ * @param assertion The first assertion to check (in a linked list)
  * @return true if assertion failed
  */
 void patch_CheckAssertions(struct Assertion *assertion);
@@ -41,4 +44,20 @@ void patch_CheckAssertions(struct Assertion *assertion);
  */
 void patch_ApplyPatches(void);
 
+/**
+ * Executes a callback on all sections referenced by a patch's expression
+ * @param patch The patch to scan the expression of
+ */
+void patch_FindRefdSections(struct Patch const *patch, void (*callback)(struct Section *),
+			    struct Symbol const * const *fileSymbols);
+
+/**
+ * Properly deletes a patch object
+ * @param patch The patch to be deleted
+ */
+static inline void patch_DeletePatch(struct Patch *patch)
+{
+	free(patch->rpnExpression);
+}
+
 #endif /* RGBDS_LINK_PATCH_H */

include/link/section.h

@@ -62,6 +62,7 @@ struct Section {
 	uint32_t nbSymbols;
 	struct Symbol const **symbols;
 	struct Section *nextu; /* The next "component" of this unionized sect */
+	bool smartLinked; // Set to true if kept by smart linking
 };
 
 /*
@@ -97,4 +98,11 @@ void sect_CleanupSections(void);
  */
 void sect_DoSanityChecks(void);
 
+/**
+ * Adds a new function as "root" of the smart link graph
+ */
+void sect_AddSmartSection(char const *name);
+
+void sect_PerformSmartLink(void);
+
 #endif /* RGBDS_LINK_SECTION_H */

include/link/symbol.h

@@ -53,6 +53,24 @@ void sym_AddSymbol(struct Symbol *symbol);
  */
 struct Symbol *sym_GetSymbol(char const *name);
 
+/**
+ * Cleanly deletes a symbol and associated data
+ * @param arg The symbol to delete
+ */
+static inline void sym_FreeSymbol(void *arg)
+{
+	struct Symbol *sym = arg;
+
+	free(sym->name);
+	free(sym);
+}
+
+/**
+ * Cleanly deletes a symbol and associated data
+ * @param name The name of the symbol to delete
+ */
+void sym_RemoveSymbol(char const *name);
+
 /**
  * `free`s all symbol memory that was allocated.
  */

src/hashmap.c

@@ -80,7 +80,7 @@ bool hash_ReplaceElement(HashMap const map, char const *key, void *element)
 	return false;
 }
 
-bool hash_RemoveElement(HashMap map, char const *key)
+void *hash_RemoveElement(HashMap map, char const *key)
 {
 	HashType hashedKey = hash(key);
 	struct HashMapEntry **ptr = &map[(HalfHashType)hashedKey];
@@ -89,14 +89,15 @@ bool hash_RemoveElement(HashMap map, char const *key)
 		if (hashedKey >> HALF_HASH_NB_BITS == (*ptr)->hash
 		 && !strcmp((*ptr)->key, key)) {
 			struct HashMapEntry *next = (*ptr)->next;
+			void *elem = (*ptr)->content;
 
 			free(*ptr);
 			*ptr = next;
-			return true;
+			return elem;
 		}
 		ptr = &(*ptr)->next;
 	}
-	return false;
+	return NULL;
 }
 
 void *hash_GetElement(HashMap const map, char const *key)
@@ -126,14 +127,16 @@ void hash_ForEach(HashMap const map, void (*func)(void *, void *), void *arg)
 	}
 }
 
-void hash_EmptyMap(HashMap map)
+void hash_EmptyMap(HashMap map, void (*callback)(void *))
 {
 	for (size_t i = 0; i < HASHMAP_NB_BUCKETS; i++) {
 		struct HashMapEntry *ptr = map[i];
 
 		while (ptr) {
 			struct HashMapEntry *next = ptr->next;
 
+			if (callback)
+				callback(ptr->content);
 			free(ptr);
 			ptr = next;
 		}

src/link/main.c

@@ -200,6 +200,8 @@ static void printUsage(void)
 static void cleanup(void)
 {
 	obj_Cleanup();
+	sym_CleanupSymbols();
+	sect_CleanupSections();
 }
 
 int main(int argc, char *argv[])
@@ -244,9 +246,7 @@ int main(int argc, char *argv[])
 			padValue = value;
 			break;
 		case 's':
-			/* FIXME: nobody knows what this does, figure it out */
-			(void)musl_optarg;
-			warning(NULL, 0, "Nobody has any idea what `-s` does");
+			sect_AddSmartSection(optarg);
 			break;
 		case 't':
 			is32kMode = true;
@@ -296,6 +296,7 @@ int main(int argc, char *argv[])
 
 	/* then process them, */
 	obj_DoSanityChecks();
+	sect_PerformSmartLink();
 	assign_AssignSections();
 	obj_CheckAssertions();
 	assign_Cleanup();

src/link/object.c

@@ -316,39 +316,31 @@ static void readSection(FILE *file, struct Section *section, char const *fileNam
 	int32_t tmp;
 	uint8_t byte;
 
-	tryReadstr(section->name, file, "%s: Cannot read section name: %s",
-		   fileName);
-	tryReadlong(tmp, file, "%s: Cannot read \"%s\"'s' size: %s",
-		    fileName, section->name);
+	tryReadstr(section->name, file, "%s: Cannot read section name: %s", fileName);
+	tryReadlong(tmp, file, "%s: Cannot read \"%s\"'s' size: %s", fileName, section->name);
 	if (tmp < 0 || tmp > UINT16_MAX)
-		errx(1, "\"%s\"'s section size (%" PRId32 ") is invalid",
-		     section->name, tmp);
+		errx(1, "\"%s\"'s section size (%" PRId32 ") is invalid", section->name, tmp);
 	section->size = tmp;
 	section->offset = 0;
-	tryGetc(byte, file, "%s: Cannot read \"%s\"'s type: %s",
-		fileName, section->name);
+	tryGetc(byte, file, "%s: Cannot read \"%s\"'s type: %s", fileName, section->name);
 	section->type = byte & 0x3F;
 	if (byte >> 7)
 		section->modifier = SECTION_UNION;
 	else if (byte >> 6)
 		section->modifier = SECTION_FRAGMENT;
 	else
 		section->modifier = SECTION_NORMAL;
-	tryReadlong(tmp, file, "%s: Cannot read \"%s\"'s org: %s",
-		    fileName, section->name);
+	tryReadlong(tmp, file, "%s: Cannot read \"%s\"'s org: %s", fileName, section->name);
 	section->isAddressFixed = tmp >= 0;
 	if (tmp > UINT16_MAX) {
-		error(NULL, 0, "\"%s\"'s org is too large (%" PRId32 ")",
-		      section->name, tmp);
+		error(NULL, 0, "\"%s\"'s org is too large (%" PRId32 ")", section->name, tmp);
 		tmp = UINT16_MAX;
 	}
 	section->org = tmp;
-	tryReadlong(tmp, file, "%s: Cannot read \"%s\"'s bank: %s",
-		    fileName, section->name);
+	tryReadlong(tmp, file, "%s: Cannot read \"%s\"'s bank: %s", fileName, section->name);
 	section->isBankFixed = tmp >= 0;
 	section->bank = tmp;
-	tryGetc(byte, file, "%s: Cannot read \"%s\"'s alignment: %s",
-		fileName, section->name);
+	tryGetc(byte, file, "%s: Cannot read \"%s\"'s alignment: %s", fileName, section->name);
 	if (byte > 16)
 		byte = 16;
 	section->isAlignFixed = byte != 0;
@@ -367,35 +359,32 @@ static void readSection(FILE *file, struct Section *section, char const *fileNam
 		uint8_t *data = malloc(sizeof(*data) * section->size + 1);
 
 		if (!data)
-			err(1, "%s: Unable to read \"%s\"'s data", fileName,
-			    section->name);
+			err(1, "%s: Unable to read \"%s\"'s data", fileName, section->name);
 		if (section->size) {
-			size_t nbElementsRead = fread(data, sizeof(*data),
-						      section->size, file);
+			size_t nbElementsRead = fread(data, sizeof(*data), section->size, file);
 			if (nbElementsRead != section->size)
 				errx(1, "%s: Cannot read \"%s\"'s data: %s",
 				     fileName, section->name,
-				     feof(file) ? "Unexpected end of file"
-						: strerror(errno));
+				     feof(file) ? "Unexpected end of file" : strerror(errno));
 		}
 		section->data = data;
 
 		tryReadlong(section->nbPatches, file,
 			    "%s: Cannot read \"%s\"'s number of patches: %s",
 			    fileName, section->name);
 
-		struct Patch *patches =
-			malloc(sizeof(*patches) * section->nbPatches + 1);
+		struct Patch *patches = malloc(sizeof(*patches) * section->nbPatches + 1);
 
 		if (!patches)
-			err(1, "%s: Unable to read \"%s\"'s patches", fileName,
-			    section->name);
+			err(1, "%s: Unable to read \"%s\"'s patches", fileName, section->name);
 		for (uint32_t i = 0; i < section->nbPatches; i++) {
 			readPatch(file, &patches[i], fileName, section->name,
 				  i, fileSections, fileNodes);
 		}
 		section->patches = patches;
 	}
+
+	section->smartLinked = false;
 }
 
 /**
@@ -614,6 +603,11 @@ void obj_DoSanityChecks(void)
 	sect_DoSanityChecks();
 }
 
+struct Assertion const *obj_GetFirstAssertion(void)
+{
+	return assertions;
+}
+
 void obj_CheckAssertions(void)
 {
 	patch_CheckAssertions(assertions);
@@ -628,27 +622,6 @@ void obj_Setup(unsigned int nbFiles)
 	nodes = malloc(sizeof(*nodes) * nbFiles);
 }
 
-static void freeSection(struct Section *section, void *arg)
-{
-	(void)arg;
-
-	free(section->name);
-	if (sect_HasData(section->type)) {
-		free(section->data);
-		for (int32_t i = 0; i < section->nbPatches; i++)
-			free(section->patches[i].rpnExpression);
-		free(section->patches);
-	}
-	free(section->symbols);
-	free(section);
-}
-
-static void freeSymbol(struct Symbol *symbol)
-{
-	free(symbol->name);
-	free(symbol);
-}
-
 void obj_Cleanup(void)
 {
 	for (unsigned int i = 0; i < nbObjFiles; i++) {
@@ -660,16 +633,11 @@ void obj_Cleanup(void)
 	}
 	free(nodes);
 
-	sym_CleanupSymbols();
-
-	sect_ForEach(freeSection, NULL);
-	sect_CleanupSections();
-
 	struct SymbolList *list = symbolLists;
 
 	while (list) {
 		for (size_t i = 0; i < list->nbSymbols; i++)
-			freeSymbol(list->symbolList[i]);
+			sym_FreeSymbol(list->symbolList[i]);
 		free(list->symbolList);
 
 		struct SymbolList *next = list->next;