cmd/5l: dwarf line number support for Linux/ARM

Part of issue 3747.

R=dave, lvd, rsc
CC=golang-dev
https://golang.org/cl/6084044

src/cmd/5l/asm.c

@@ -33,6 +33,7 @@
 #include	"l.h"
 #include	"../ld/lib.h"
 #include	"../ld/elf.h"
+#include	"../ld/dwarf.h"
 
 static Prog *PP;
 
@@ -509,6 +510,7 @@ doelf(void)
 	if(!debug['s']) {
 		elfstr[ElfStrSymtab] = addstring(shstrtab, ".symtab");
 		elfstr[ElfStrStrtab] = addstring(shstrtab, ".strtab");
+		dwarfaddshstrings(shstrtab);
 	}
 	elfstr[ElfStrShstrtab] = addstring(shstrtab, ".shstrtab");
 
@@ -723,12 +725,11 @@ asmb(void)
 			cflush();
 			cwrite(elfstrdat, elfstrsize);
 
-			// if(debug['v'])
+			if(debug['v'])
-			// 	Bprint(&bso, "%5.2f dwarf\n", cputime());
+				Bprint(&bso, "%5.2f dwarf\n", cputime());
-			// dwarfemitdebugsections();
+			dwarfemitdebugsections();
 		}
 		cflush();
-		
 	}
 
 	cursym = nil;
@@ -989,7 +990,7 @@ asmb(void)
 			sh->size = elfstrsize;
 			sh->addralign = 1;
 
-			// dwarfaddelfheaders();
+			dwarfaddelfheaders();
 		}
 
 		/* Main header */
@@ -2317,9 +2318,3 @@ genasmsym(void (*put)(Sym*, char*, int, vlong, vlong, int, Sym*))
 		Bprint(&bso, "symsize = %ud\n", symsize);
 	Bflush(&bso);
 }
-
-void
-setpersrc(Sym *s)
-{
-	USED(s);
-}

src/cmd/5l/l.h

@@ -401,6 +401,9 @@ void	span(void);
 void	strnput(char*, int);
 int32	symaddr(Sym*);
 void	undef(void);
+void	vputb(uint64);
+void	vputl(uint64);
+void	wputb(uint16);
 void	wput(int32);
 void    wputl(ushort w);
 void	xdefine(char*, int, int32);
@@ -428,3 +431,9 @@ vlong		adduintxx(Sym *s, uint64 v, int wid);
 #define	VPUT(a)	abort()
 
 #endif
+
+/* Used by ../ld/dwarf.c */
+enum
+{
+	DWARFREGSP = 13
+};

src/cmd/5l/noop.c

@@ -365,11 +365,7 @@ noops(void)
 				q1 = p;
 	
 				/* MOV a,4(SP) */
-				q = prg();
+				p = appendp(p);
-				q->link = p->link;
-				p->link = q;
-				p = q;
-	
 				p->as = AMOVW;
 				p->line = q1->line;
 				p->from.type = D_REG;
@@ -379,11 +375,7 @@ noops(void)
 				p->to.offset = 4;
 	
 				/* MOV b,REGTMP */
-				q = prg();
+				p = appendp(p);
-				q->link = p->link;
-				p->link = q;
-				p = q;
-	
 				p->as = AMOVW;
 				p->line = q1->line;
 				p->from.type = D_REG;
@@ -395,11 +387,7 @@ noops(void)
 				p->to.offset = 0;
 	
 				/* CALL appropriate */
-				q = prg();
+				p = appendp(p);
-				q->link = p->link;
-				p->link = q;
-				p = q;
-	
 				p->as = ABL;
 				p->line = q1->line;
 				p->to.type = D_BRANCH;
@@ -424,11 +412,7 @@ noops(void)
 				}
 	
 				/* MOV REGTMP, b */
-				q = prg();
+				p = appendp(p);
-				q->link = p->link;
-				p->link = q;
-				p = q;
-	
 				p->as = AMOVW;
 				p->line = q1->line;
 				p->from.type = D_REG;
@@ -438,12 +422,9 @@ noops(void)
 				p->to.reg = q1->to.reg;
 	
 				/* ADD $8,SP */
-				q = prg();
+				p = appendp(p);
-				q->link = p->link;
-				p->link = q;
-				p = q;
-	
 				p->as = AADD;
+				p->line = q1->line;
 				p->from.type = D_CONST;
 				p->from.reg = NREG;
 				p->from.offset = 8;

src/cmd/5l/obj.c

@@ -34,6 +34,7 @@
 #include	"l.h"
 #include	"../ld/lib.h"
 #include	"../ld/elf.h"
+#include	"../ld/dwarf.h"
 #include	<ar.h>
 
 #ifndef	DEFAULT
@@ -481,6 +482,7 @@ loop:
 				histfrogp++;
 			} else
 				collapsefrog(s);
+			dwarfaddfrag(s->value, s->name);
 		}
 		goto loop;
 	}

src/cmd/5l/softfloat.c

@@ -76,6 +76,7 @@ softfloat(void)
 	 				p->to.type = D_BRANCH;
 					p->to.sym = symsfloat;
 					p->cond = psfloat;
+					p->line = next->line;
 	
 					p = next;
 					wasfloat = 1;

src/cmd/5l/span.c

@@ -288,12 +288,20 @@ flushpool(Prog *p, int skip, int force)
 			q->to.type = D_BRANCH;
 			q->cond = p->link;
 			q->link = blitrl;
+			q->line = p->line;
 			blitrl = q;
 		}
 		else if(!force && (p->pc+pool.size-pool.start < 2048))
 			return 0;
 		elitrl->link = p->link;
 		p->link = blitrl;
+		// BUG(minux): how to correctly handle line number for constant pool entries?
+		// for now, we set line number to the last instruction preceding them at least
+		// this won't bloat the .debug_line tables
+		while(blitrl) {
+			blitrl->line = p->line;
+			blitrl = blitrl->link;
+		}
 		blitrl = 0;	/* BUG: should refer back to values until out-of-range */
 		elitrl = 0;
 		pool.size = 0;

src/cmd/dist/build.c

@@ -474,14 +474,7 @@ static struct {
 		"$GOROOT/pkg/obj/$GOOS_$GOARCH/libgc.a",
 	}},
 	{"cmd/5l", {
-		"../ld/data.c",
+		"../ld/*",
-		"../ld/elf.c",
-		"../ld/go.c",
-		"../ld/ldelf.c",
-		"../ld/ldmacho.c",
-		"../ld/ldpe.c",
-		"../ld/lib.c",
-		"../ld/symtab.c",
 		"enam.c",
 	}},
 	{"cmd/6l", {