8l: emit DWARF in ELF.

R=rsc, r, ken2
CC=golang-dev
https://golang.org/cl/2004046

src/cmd/6l/asm.c

@@ -641,8 +641,7 @@ asmb(void)
 
                         dwarfemitdebugsections();
 		}
-	} else
-	if(dlm){
+	} else if(dlm){
 		seek(cout, HEADR+textsize+datsize, 0);
 		asmdyn();
 		cflush();

src/cmd/6l/l.h

@@ -394,9 +394,9 @@ Prog*	brchain(Prog*);
 Prog*	brloop(Prog*);
 void	buildop(void);
 void	cflush(void);
-vlong   cpos(void);
 void	ckoff(Sym*, int32);
 Prog*	copyp(Prog*);
+vlong   cpos(void);
 double	cputime(void);
 void	datblk(int32, int32);
 void	deadcode(void);

src/cmd/8l/Makefile

@@ -9,8 +9,10 @@ TARG=8l
 
 OFILES=\
 	asm.$O\
+	dwarf.$O\
 	elf.$O\
 	enam.$O\
+	go.$O\
 	lib.$O\
 	list.$O\
 	macho.$O\
@@ -19,11 +21,12 @@ OFILES=\
 	pass.$O\
 	pe.$O\
 	span.$O\
-	go.$O\
+
 
 HFILES=\
 	l.h\
 	../8l/8.out.h\
+	../ld/dwarf.h\
 	../ld/elf.h\
 	../ld/macho.h\
 	../ld/pe.h\

src/cmd/8l/asm.c

@@ -31,6 +31,7 @@
 #include	"l.h"
 #include	"../ld/lib.h"
 #include	"../ld/elf.h"
+#include	"../ld/dwarf.h"
 #include	"../ld/macho.h"
 #include	"../ld/pe.h"
 
@@ -293,6 +294,7 @@ doelf(void)
 		elfstr[ElfStrGosymcounts] = addstring(shstrtab, ".gosymcounts");
 		elfstr[ElfStrGosymtab] = addstring(shstrtab, ".gosymtab");
 		elfstr[ElfStrGopclntab] = addstring(shstrtab, ".gopclntab");
+                dwarfaddshstrings(shstrtab);
 	}
 	elfstr[ElfStrShstrtab] = addstring(shstrtab, ".shstrtab");
 
@@ -649,8 +651,13 @@ asmb(void)
 		lputl(symsize);
 		lputl(lcsize);
 		cflush();
+                if(!debug['s']) {
+                        seek(cout, symo+8+symsize+lcsize, 0);
+                        if(debug['v'])
+                               Bprint(&bso, "%5.2f dwarf\n", cputime());
+                        dwarfemitdebugsections();
 		}
-	else if(dlm){
+	} else if(dlm){
 		seek(cout, HEADR+textsize+datsize, 0);
 		asmdyn();
 		cflush();
@@ -1042,6 +1049,8 @@ asmb(void)
 			sh->size = w;
 			sh->addralign = 1;
 			sh->addr = symdatva + 8 + symsize;
+
+                        dwarfaddheaders();
 		}
 
 		sh = newElfShstrtab(elfstr[ElfStrShstrtab]);
@@ -1118,6 +1127,13 @@ cflush(void)
 	cbc = sizeof(buf.cbuf);
 }
 
+/* Current position in file */
+vlong
+cpos(void)
+{
+        return seek(cout, 0, 1) + sizeof(buf.cbuf) - cbc;
+}
+
 void
 datblk(int32 s, int32 n)
 {

src/cmd/8l/l.h

@@ -345,6 +345,7 @@ Prog*	brloop(Prog*);
 void	cflush(void);
 void	ckoff(Sym*, int32);
 Prog*	copyp(Prog*);
+vlong   cpos(void);
 double	cputime(void);
 void	datblk(int32, int32);
 void	diag(char*, ...);

src/cmd/8l/obj.c

@@ -33,6 +33,7 @@
 #include	"../ld/lib.h"
 #include	"../ld/elf.h"
 #include	"../ld/macho.h"
+#include	"../ld/dwarf.h"
 #include	"../ld/pe.h"
 #include	<ar.h>
 
@@ -604,6 +605,7 @@ loop:
 				histfrogp++;
 			} else
 				collapsefrog(s);
+                        dwarfaddfrag(s->value, s->name);
 		}
 		goto loop;
 	}

src/cmd/ld/dwarf.c

@@ -39,6 +39,7 @@ enum
 {
 	DW_ABRV_NULL,
 	DW_ABRV_COMPUNIT,
+	DW_ABRV_FUNCTION,
 	DW_NABRV
 };
 
@@ -60,6 +61,14 @@ struct DWAbbrev {
 		DW_AT_stmt_list, DW_FORM_data4,
 		0, 0
 	},
+	/* FUNCTION */
+	{
+		DW_TAG_subprogram, DW_CHILDREN_no,
+		DW_AT_name,	 DW_FORM_string,
+		DW_AT_low_pc,	 DW_FORM_addr,
+		DW_AT_high_pc,	 DW_FORM_addr,
+		0, 0
+	},
 };
 
 /*
@@ -116,6 +125,18 @@ newattr(DWDie *die, uint8 attr, int cls, vlong value, char *data)
 	return a;
 }
 
+static void addrput(vlong addr)
+{
+	switch(PtrSize) {
+	case 4:
+		LPUT(addr);
+		break;
+	case 8:
+		VPUT(addr);
+		break;
+	}
+}
+
 static void
 uleb128put(uvlong v)
 {
@@ -149,7 +170,7 @@ putattr(int form, int cls, vlong value, char *data)
 {
 	switch(form) {
 	case DW_FORM_addr:	// address
-                VPUT(value);
+		addrput(value);
 		break;
 
 	case DW_FORM_block1:	// block
@@ -280,6 +301,17 @@ reverselist(DWDie** list)
 	*list = prev;
 }
 
+static void
+reversetree(DWDie** list)
+{
+	 DWDie *die;
+
+	 reverselist(list);
+	 if (*list != nil && abbrevs[(*list)->abbrev].children)
+		 for (die = *list; die != nil; die = die->link)
+			 reversetree(&die->child);
+}
+
 /*
  * Filename fragments for the line history stack.
  */
@@ -320,7 +352,7 @@ decodez(char *s)
 			return 0;
 		}
 		f = ftab[o];
-		if (!f) {
+		if (f == nil) {
 			diag("corrupt z entry");
 			return 0;
 		}
@@ -667,24 +699,34 @@ writelines(void)
 				strnput(histfile[i], strlen(histfile[i]) + 4);
 				// 4 zeros: the string termination + 3 fields.
 			}
+
 			pc = p->pc;
 			currfile = 1;
 			lc = 1;
 			llc = 1;
+
 			cput(0);  // start extended opcode
-                        uleb128put(1 + sizeof pc);
+			uleb128put(1 + PtrSize);
 			cput(DW_LNE_set_address);
-                        VPUT(pc);
+			addrput(pc);
 		}
 		if (!p->from.sym->reachable)
 			continue;
 		if (unitstart < 0) {
-                        diag("Reachable code before seeing any history: %P", p);
+			diag("reachable code before seeing any history: %P", p);
 			continue;
 		}
+
+		dwinfo->child = newdie(dwinfo->child, DW_ABRV_FUNCTION);
+		newattr(dwinfo->child, DW_AT_name, DW_CLS_STRING, strlen(s->name), s->name);
+		newattr(dwinfo->child, DW_AT_low_pc, DW_CLS_ADDRESS, p->pc, 0);
+		if (debug['v'] > 1)
+		  print("frame offset: %d\n", p->to.offset);
+//		newattr(dwinfo->child, DW_AT_return_addr,  DW_CLS_BLOCK, p->to.offset, 0);
+
 		for(q = p; q != P && (q == p || q->as != ATEXT); q = q->link) {
 			lh = searchhist(q->line);
-                        if (!lh) {
+			if (lh == nil) {
 				diag("corrupt history or bad absolute line: %P", q);
 				continue;
 			}
@@ -704,6 +746,7 @@ writelines(void)
 			lc  = q->line;
 			llc = lline;
 		}
+		newattr(dwinfo->child, DW_AT_high_pc, DW_CLS_ADDRESS, pc, 0);
 	}
 	flushunit(pc, unitstart);
 	linesize = cpos() - lineo;
@@ -718,7 +761,7 @@ writeinfo(void)
 	DWDie *compunit;
 	vlong unitstart;
 
-        reverselist(&dwinfo);
+	reversetree(&dwinfo);
 
 	infoo = cpos();
 
@@ -730,7 +773,7 @@ writeinfo(void)
 		LPUT(0);   // unit_length (*), will be filled in later.
 		WPUT(3);   // version
 		LPUT(0);   // debug_abbrev_offset (*)
-                cput(8);   // address_size
+		cput(PtrSize);	 // address_size
 
 		putdie(compunit);
 
@@ -749,7 +792,8 @@ writeinfo(void)
 /*
  *  Elf sections.
  */
-enum {
+enum
+{
 	ElfStrDebugAbbrev,
 	ElfStrDebugAranges,
 	ElfStrDebugFrame,