Implement compact file stacks in object files

Gets rid of `open_memstream`, enabling Windows compatibility again
Also fixes #491 as a nice bonus!

include/link/main.h

@@ -29,15 +29,45 @@ extern bool beVerbose;
 extern bool isWRA0Mode;
 extern bool disablePadding;
 
+struct FileStackNode {
+	struct FileStackNode *parent;
+	/* Line at which the parent context was exited; meaningless for the root level */
+	uint32_t lineNo;
+
+	enum {
+		NODE_REPT,
+		NODE_FILE,
+		NODE_MACRO,
+	} type;
+	union {
+		char *name; /* NODE_FILE, NODE_MACRO */
+		struct { /* NODE_REPT */
+			uint32_t reptDepth;
+			uint32_t *iters;
+		};
+	};
+};
+
 /* Helper macro for printing verbose-mode messages */
 #define verbosePrint(...)   do { \
 					if (beVerbose) \
 						fprintf(stderr, __VA_ARGS__); \
 				} while (0)
 
-void error(char const *fmt, ...);
+/**
+ * Dump a file stack to stderr
+ * @param node The leaf node to dump the context of
+ */
+char const *dumpFileStack(struct FileStackNode const *node);
 
-noreturn_ void fatal(char const *fmt, ...);
+void warning(struct FileStackNode const *where, uint32_t lineNo,
+	     char const *fmt, ...) format_(printf, 3, 4);
+
+void error(struct FileStackNode const *where, uint32_t lineNo,
+	   char const *fmt, ...) format_(printf, 3, 4);
+
+noreturn_ void fatal(struct FileStackNode const *where, uint32_t lineNo,
+		     char const *fmt, ...) format_(printf, 3, 4);
 
 /**
  * Opens a file if specified, and aborts on error.

include/link/object.h

@@ -14,8 +14,9 @@
 /**
  * Read an object (.o) file, and add its info to the data structures.
  * @param fileName A path to the object file to be read
+ * @param i The ID of the file
  */
-void obj_ReadFile(char const *fileName);
+void obj_ReadFile(char const *fileName, unsigned int i);
 
 /**
  * Perform validation on the object files' contents
@@ -27,6 +28,12 @@ void obj_DoSanityChecks(void);
  */
 void obj_CheckAssertions(void);
 
+/**
+ * Sets up object file reading
+ * @param nbFiles The number of object files that will be read
+ */
+void obj_Setup(unsigned int nbFiles);
+
 /**
  * `free`s all object memory that was allocated.
  */

include/link/section.h

@@ -19,6 +19,7 @@
 
 #include "linkdefs.h"
 
+struct FileStackNode;
 struct Section;
 
 struct AttachedSymbol {
@@ -27,7 +28,8 @@ struct AttachedSymbol {
 };
 
 struct Patch {
-	char *fileName;
+	struct FileStackNode const *src;
+	uint32_t lineNo;
 	int32_t offset;
 	uint32_t pcSectionID;
 	uint32_t pcOffset;

include/link/symbol.h

@@ -16,12 +16,14 @@
 
 #include "linkdefs.h"
 
+struct FileStackNode;
+
 struct Symbol {
 	/* Info contained in the object files */
 	char *name;
 	enum ExportLevel type;
 	char const *objFileName;
-	char *fileName;
+	struct FileStackNode const *src;
 	int32_t lineNo;
 	int32_t sectionID;
 	union {