Support -g debug info generation

-Add GenLineNoSym(), which will generate debug
 symbols for file names and line numbers when
 debug info generation is requested.

-Replace code that warns -g is not supported with
 code to set a flag.

-Complain if -g is specified for non-BSD output
 formats, as only stabs-in-symbol-table/a.out
 format debug information is supported currently.

-Document -g flag in usage information function.

-Document -g flag in manual.

v2:
-Only call debug symbol generation functions when
 dbg_sym != 0

6502.c

@@ -423,6 +423,8 @@ badmode:
 	DEBUG printf("inf[op][amode]=%d\n", (int)inf[op][amode]);
 #endif
 
+	GENLINENOSYM();
+
 	switch (inf[op][amode])
 	{
 		case A65_IMPL:		// Just leave the instruction

docs/rmac.rst

@@ -125,6 +125,7 @@ Switch               Description
 -fe                  ELF output object file format.
 -fr                  Absolute address. Source code is required to have one .org statement.
 -fx                  Atari 800 com/exe/xex output object file format.
+-g                   Generate source level debug info. Requires BSD COFF object file format.
 -i\ *path*           Set include-file directory search path.
 -l\ *[file[prn]]*    Construct and direct assembly listing to the specified file.
 -l\ *\*[filename]*   Create an output listing file without pagination.
@@ -235,6 +236,19 @@ the table.
  file is created. Beware! If an assembly produces no errors, any error file from
  a previous assembly is not removed.
 
+**-g**
+ The **-g** switch causes RMAC to generate source-level debug symbols using the
+ stabs format. When linked with a compatible linker such as RLN, these symbols
+ can be used by source-level debuggers such as rdbjag, wdb, or gdb to step
+ through assembly code line-by-line with all the additional context of labels,
+ macros, constants, register equates, etc. available in the original assembly
+ listings rather than relying on the simple disassembly or raw machine code
+ available when stepping through instruction-by-instruction. This option only
+ works with the BSD COFF object file format, as the others do not use the
+ a.out-style symbol tables required by stabs, and RMAC does not currently
+ support placing stabs debug symbols in their own dedicated section in ELF
+ format object files.
+
 **-i**
  The **-i** switch allows automatic directory searching for include files. A list of
  semi-colon seperated directory search paths may be mentioned immediately

op.c

@@ -46,6 +46,11 @@ int GenerateOPCode(int state)
 	if (!robjproc)
 		return error("opcode only valid in OP mode");
 
+	// It's OK to call this before validating state. If the state is invalid, an
+	// error will be generated and no object file will be produced, so it
+	// doesn't matter if the line number symbols are a little off.
+	GENLINENOSYM();
+
 	switch (state)
 	{
 	case MO_BITMAP:

procln.c

@@ -739,6 +739,7 @@ When checking to see if it's already been equated, issue a warning.
 			while ((dsp_am0 & md->mn0) == 0 || (dsp_am1 & md->mn1) == 0)
 				md = &dsp56k_machtab[md->mncont];
 
+			GENLINENOSYM();
 			(*md->mnfunc)(md->mninst | (parcode << 8));
 			goto loop;
 		}
@@ -784,6 +785,7 @@ When checking to see if it's already been equated, issue a warning.
 	// Call special-mode handler
 	if (m->mnattr & CGSPECIAL)
 	{
+		GENLINENOSYM();
 		(*m->mnfunc)(m->mninst, siz);
 		goto loop;
 	}
@@ -818,6 +820,7 @@ When checking to see if it's already been equated, issue a warning.
 
 	DEBUG { printf("    68K: mninst=$%X, siz=$%X, mnattr=$%X, amsk0=$%X, mn0=$%X, amsk1=$%X, mn1=$%X\n", m->mninst, siz, m->mnattr, amsk0, m->mn0, amsk1, m->mn1); }
 
+	GENLINENOSYM();
 	(*m->mnfunc)(m->mninst, siz);
 	goto loop;
 }

riscasm.c

@@ -190,6 +190,7 @@ static void DepositRISCInstructionWord(uint16_t opcode, int reg1, int reg2)
 	}
 
 	int value = ((opcode & 0x3F) << 10) + ((reg1 & 0x1F) << 5) + (reg2 & 0x1F);
+	GENLINENOSYM();
 	D_word(value);
 }
 

rmac.c

@@ -31,6 +31,7 @@ int verb_flag;					// Be verbose about what's going on
 int m6502;						// 1, assembling 6502 code
 int glob_flag;					// Assume undefined symbols are global
 int lsym_flag;					// Include local symbols in object file (ALWAYS true)
+int dsym_flag;					// Gen debug syms (Requires obj_format = BSD)
 int optim_warn_flag;			// Warn about possible short branches
 int prg_flag;					// !=0, produce .PRG executable (2=symbols)
 int prg_extend;					// !=0, output extended .PRG symbols
@@ -167,6 +168,7 @@ void DisplayHelp(void)
 		"                    l: LOD (use this for DSP56001 only)\n"
 		"                    x: com/exe/xex (Atari 800)\n"
 		"                    r: absolute address\n"
+		"  -g                Output source level debug information (BSD object only)\n"
 		"  -i[path]          Directory to search for include files\n"
 		"  -l[filename]      Create an output listing file\n"
 		"  -l*[filename]     Create an output listing file without pagination\n"
@@ -290,6 +292,42 @@ int ParseOptimization(char * optstring)
 	return OK;
 }
 
+static void ProcessFile(int fd, char *fname)
+{
+	char *dbgname = fname;
+
+	if (NULL == fname)
+	{
+		fname = defname; // Kludge first filename
+		dbgname = "(stdin)";
+	}
+
+	// First file operations:
+	if (firstfname == NULL)
+	{
+		// Record first filename.
+		firstfname = fname;
+
+		// Validate option compatibility
+		if (dsym_flag)
+		{
+			if (obj_format != BSD)
+			{
+				printf("-g: debug information only supported with BSD object file format\n");
+				dsym_flag = 0;
+				errcnt++;
+			}
+			else
+			{
+				GenMainFileSym(dbgname);
+			}
+		}
+	}
+
+	include(fd, dbgname);
+	Assemble();
+}
+
 extern int reg68base[53];
 extern int reg68tab[222];
 extern int reg68check[222];
@@ -326,6 +364,7 @@ int Process(int argc, char ** argv)
 	rdsp = 0;						// Initialize DSP assembly flag
 	robjproc = 0;					// Initialize OP assembly flag
 	lsym_flag = 1;					// Include local symbols in object file
+	dsym_flag = 0;					// No debug sym generation by default
 	orgactive = 0;					// Not in RISC org section
 	orgwarning = 0;					// No ORG warning issued
 	segpadsize = 2;					// Initialize segment padding size
@@ -432,7 +471,7 @@ int Process(int argc, char ** argv)
 				break;
 			case 'g':				// Debugging flag
 			case 'G':
-				printf("Debugging flag (-g) not yet implemented\n");
+				dsym_flag = 1;
 				break;
 			case 'i':				// Set directory search path
 			case 'I':
@@ -607,11 +646,7 @@ int Process(int argc, char ** argv)
 
 				break;
 			case EOS:				// Input is stdin
-				if (firstfname == NULL)	// Kludge first filename
-					firstfname = defname;
-
-				include(0, "(stdin)");
-				Assemble();
+				ProcessFile(0, NULL);
 				break;
 			case 'h':				// Display command line usage
 			case 'H':
@@ -646,10 +681,6 @@ int Process(int argc, char ** argv)
 		}
 		else
 		{
-			// Record first filename.
-			if (firstfname == NULL)
-				firstfname = argv[argno];
-
 			strcpy(fnbuf, argv[argno]);
 			fext(fnbuf, ".s", 0);
 			fd = open(fnbuf, 0);
@@ -661,8 +692,7 @@ int Process(int argc, char ** argv)
 				continue;
 			}
 
-			include(fd, fnbuf);
-			Assemble();
+			ProcessFile(fd, fnbuf);
 		}
 	}
 

rmac.h

@@ -28,6 +28,7 @@
 	#define _OPEN_INC       _O_RDONLY|_O_BINARY
 	#define _PERM_MODE      _S_IREAD|_S_IWRITE
     #define PATH_SEPS       ";"
+    #define realpath(_fn, _abs) _fullpath((_abs), (_fn), _MAX_PATH)
 
 	#ifdef _MSC_VER
 		#if _MSC_VER > 1000
@@ -302,6 +303,7 @@ extern int m6502;
 extern int list_flag;
 extern int glob_flag;
 extern int lsym_flag;
+extern int dsym_flag;
 extern int optim_warn_flag;
 extern int obj_format;
 extern int legacy_flag;

symbol.c

@@ -58,7 +58,7 @@ void InitSymbolTable(void)
 //
 // Hash the ASCII name and enviroment number
 //
-int HashSymbol(uint8_t * name, int envno)
+int HashSymbol(const uint8_t * name, int envno)
 {
 	int sum = envno, k = 0;
 
@@ -76,7 +76,7 @@ int HashSymbol(uint8_t * name, int envno)
 //
 // Make a new symbol of type 'type' in enviroment 'envno'
 //
-SYM * NewSymbol(uint8_t * name, int type, int envno)
+SYM * NewSymbol(const uint8_t * name, int type, int envno)
 {
 	// Allocate the symbol
 	SYM * symbol = malloc(sizeof(SYM));
@@ -565,12 +565,12 @@ int symtable(void)
 	return 0;
 }
 
-SYM * NewDebugSymbol(uint8_t * str, uint8_t type, uint8_t other, uint16_t desc)
+SYM * NewDebugSymbol(const uint8_t * str, uint8_t type, uint8_t other, uint16_t desc)
 {
 	SYM * symbol = NewSymbol(str, DBGSYM, 0);
 
 	if (NULL == symbol)
-		return NULL;
+		fatal("Could not allocate space for debug symbol");
 
 	AddToSymbolDeclarationList(symbol);
 
@@ -580,3 +580,101 @@ SYM * NewDebugSymbol(uint8_t * str, uint8_t type, uint8_t other, uint16_t desc)
 
 	return symbol;
 }
+
+char *FilePath(const char * fname)
+{
+	char buf1[256];
+	char * fpath;
+	int i, j;
+
+	if ((fpath = realpath(fname, NULL)) != NULL)
+		return fpath;
+
+	for(i=0; nthpath("RMACPATH", i, buf1)!=0; i++)
+	{
+		j = strlen(buf1);
+
+		// Append path char if necessary
+		if (j > 0 && buf1[j - 1] != SLASHCHAR)
+			strcat(buf1, SLASHSTRING);
+
+		strcat(buf1, fname);
+
+		if ((fpath = realpath(buf1, NULL)) != NULL)
+			return fpath;
+	}
+
+	return NULL;
+}
+
+static void GenFileSym(const char * fname, uint8_t type, uint32_t addr, uint32_t sattr)
+{
+	char *fpath;
+
+	if (!(fpath = FilePath(fname)))
+	{
+		// Don't treat this as an error. Any file rmac can read is valid enough.
+		// Just use the relative filename in place of an absolute path for the
+		// debug information.
+		fpath = strdup(fname);
+
+		if (!fpath)
+			fatal("Could not allocate memory for fake path name");
+	}
+
+	SYM * symbol = NewDebugSymbol(fpath, type, 0, 0);
+
+	free(fpath);
+
+	symbol->svalue = addr;
+	symbol->sattr |= sattr;
+}
+
+void GenMainFileSym(const char * fname)
+{
+	GenFileSym(fname, 0x64 /* N_SO */, 0, DEFINED | TEXT);
+}
+
+void GenLineNoSym(void)
+{
+	uint32_t addr;
+	uint32_t sattr;
+	uint8_t type;
+	SYM * symbol;
+
+	static uint16_t prevlineno = -1;
+	static uint32_t prevaddr = -1;
+	static uint16_t prevfileno = 0;
+
+	if (orgactive)
+	{
+		addr = orgaddr;
+		sattr = ABS | DEFINED | EQUATED;
+		// 0x4c is N_FLINE, function start/body/end line number, repurposed by
+		// MADMAC/ALN for ABS line numbers.
+		type = 0x4c;
+	}
+	else
+	{
+		addr = pcloc;
+		sattr = DEFINED | cursect;
+		type = 0x44; // N_SLINE, text section line number
+	}
+
+	if ((addr == prevaddr) || ((curlineno == prevlineno) && (prevfileno == cfileno)))
+		return;
+
+	prevaddr = addr;
+	prevlineno = curlineno;
+
+	if (prevfileno != cfileno)
+		GenFileSym(curfname, 0x84 /* N_SOL */, addr, sattr);
+
+	prevfileno = cfileno;
+
+	/* MADMAC counts lines starting at 0. Offset curlineno accordingly */
+	symbol = NewDebugSymbol(NULL, type, 0, curlineno - 1);
+
+	symbol->svalue = addr;
+	symbol->sattr |= sattr;
+}

symbol.h

@@ -49,7 +49,7 @@ extern uint32_t firstglobal;// Index of the fist global symbol in an ELF object.
 // Exported functions
 SYM * lookup(uint8_t *, int, int);
 void InitSymbolTable(void);
-SYM * NewSymbol(uint8_t *, int, int);
+SYM * NewSymbol(const uint8_t *, int, int);
 void AddToSymbolDeclarationList(SYM *);
 void ForceUndefinedSymbolsGlobal(void);
 int symtable(void);
@@ -57,7 +57,12 @@ uint32_t AssignSymbolNos(uint8_t *, uint8_t *(*)());
 uint32_t AssignSymbolNosELF(uint8_t *, uint8_t *(*)());
 void DumpLODSymbols(void);
 uint8_t * GetSymbolNameByUID(uint32_t);
-SYM * NewDebugSymbol(uint8_t *, uint8_t, uint8_t, uint16_t);
+SYM * NewDebugSymbol(const uint8_t *, uint8_t, uint8_t, uint16_t);
+void GenMainFileSym(const char *);
+void GenLineNoSym(void);
+
+// Helper to avoid unnecessary branches:
+#define GENLINENOSYM() if (dsym_flag) GenLineNoSym()
 
 #endif // __SYMBOL_H__