liblink: create new library based on linker code

There is an enormous amount of code moving around in this CL,
but the code is the same, and it is invoked in the same ways.
This CL is preparation for the new linker structure, not the new
structure itself.

The new library's definition is in include/link.h.

The main change is the use of a Link structure to hold all the
linker-relevant state, replacing the smattering of global variables.
The Link structure should both make it clearer which state must
be carried around and make it possible to parallelize more easily
later.

The main body of the linker has moved into the architecture-independent
cmd/ld directory. That includes the list of known header types, so the
distinction between Hplan9x32 and Hplan9x64 is removed (no other
header type distinguished 32- and 64-bit formats), and code for unused
formats such as ipaq kernels has been deleted.

The code being deleted from 5l, 6l, and 8l reappears in liblink or in ld.
Because multiple files are being merged in the liblink directory,
it is not possible to show the diffs nicely in hg.

The Prog and Addr structures have been unified into an
architecture-independent form and moved to link.h, where they will
be shared by all tools: the assemblers, the compilers, and the linkers.
The unification makes it possible to write architecture-independent
traversal of Prog lists, among other benefits.

The Sym structures cannot be unified: they are too fundamentally
different between the linker and the compilers. Instead, liblink defines
an LSym - a linker Sym - to be used in the Prog and Addr structures,
and the linker now refers exclusively to LSyms. The compilers will
keep using their own syms but will fill out the corresponding LSyms in
the Prog and Addr structures.

Although code from 5l, 6l, and 8l is now in a single library, the
code has been arranged so that only one architecture needs to
be linked into a particular program: 5l will not contain the code
needed for x86 instruction layout, for example.

The object file writing code in liblink/obj.c is from cmd/gc/obj.c.

Preparation for golang.org/s/go13linker work.

This CL does not build by itself. It depends on 35740044
and will be submitted at the same time.

R=iant
CC=golang-dev
https://golang.org/cl/35790044

1 files changed, 43 insertions, 43 deletions

diff --git a/src/cmd/ld/dwarf.c b/src/cmd/ld/dwarf.c
index c832bcc944..8170abe335 100644
--- a/src/cmd/ld/dwarf.c
+++ b/src/cmd/ld/dwarf.c
@@ -27,19 +27,19 @@
 
 static vlong abbrevo;
 static vlong abbrevsize;
-static Sym*  abbrevsym;
+static LSym*  abbrevsym;
 static vlong abbrevsympos;
 static vlong lineo;
 static vlong linesize;
-static Sym*  linesym;
+static LSym*  linesym;
 static vlong linesympos;
 static vlong infoo;	// also the base for DWDie->offs and reference attributes.
 static vlong infosize;
-static Sym*  infosym;
+static LSym*  infosym;
 static vlong infosympos;
 static vlong frameo;
 static vlong framesize;
-static Sym*  framesym;
+static LSym*  framesym;
 static vlong framesympos;
 static vlong pubnameso;
 static vlong pubnamessize;
@@ -50,19 +50,19 @@ static vlong arangessize;
 static vlong gdbscripto;
 static vlong gdbscriptsize;
 
-static Sym *infosec;
+static LSym *infosec;
 static vlong inforeloco;
 static vlong inforelocsize;
 
-static Sym *arangessec;
+static LSym *arangessec;
 static vlong arangesreloco;
 static vlong arangesrelocsize;
 
-static Sym *linesec;
+static LSym *linesec;
 static vlong linereloco;
 static vlong linerelocsize;
 
-static Sym *framesec;
+static LSym *framesec;
 static vlong framereloco;
 static vlong framerelocsize;
 
@@ -594,7 +594,7 @@ find_or_diag(DWDie *die, char* name)
 }
 
 static void
-adddwarfrel(Sym* sec, Sym* sym, vlong offsetbase, int siz, vlong addend)
+adddwarfrel(LSym* sec, LSym* sym, vlong offsetbase, int siz, vlong addend)
 {
 	Reloc *r;
 
@@ -639,8 +639,8 @@ putattr(int abbrev, int form, int cls, vlong value, char *data)
 	switch(form) {
 	case DW_FORM_addr:	// address
 		if(linkmode == LinkExternal) {
-			value -= ((Sym*)data)->value;
-			adddwarfrel(infosec, (Sym*)data, infoo, PtrSize, value);
+			value -= ((LSym*)data)->value;
+			adddwarfrel(infosec, (LSym*)data, infoo, PtrSize, value);
 			break;
 		}
 		addrput(value);
@@ -651,8 +651,8 @@ putattr(int abbrev, int form, int cls, vlong value, char *data)
 			cput(1+PtrSize);
 			cput(DW_OP_addr);
 			if(linkmode == LinkExternal) {
-				value -= ((Sym*)data)->value;
-				adddwarfrel(infosec, (Sym*)data, infoo, PtrSize, value);
+				value -= ((LSym*)data)->value;
+				adddwarfrel(infosec, (LSym*)data, infoo, PtrSize, value);
 				break;
 			}
 			addrput(value);
@@ -847,7 +847,7 @@ newmemberoffsetattr(DWDie *die, int32 offs)
 // GDB doesn't like DW_FORM_addr for DW_AT_location, so emit a
 // location expression that evals to a const.
 static void
-newabslocexprattr(DWDie *die, vlong addr, Sym *sym)
+newabslocexprattr(DWDie *die, vlong addr, LSym *sym)
 {
 	newattr(die, DW_AT_location, DW_CLS_ADDRESS, addr, (char*)sym);
 }
@@ -864,12 +864,12 @@ enum {
 static DWDie* defptrto(DWDie *dwtype);	// below
 
 // Lookup predefined types
-static Sym*
+static LSym*
 lookup_or_diag(char *n)
 {
-	Sym *s;
+	LSym *s;
 
-	s = rlookup(n, 0);
+	s = linkrlookup(ctxt, n, 0);
 	if (s == nil || s->size == 0) {
 		diag("dwarf: missing type: %s", n);
 		errorexit();
@@ -904,10 +904,10 @@ dotypedef(DWDie *parent, char *name, DWDie *def)
 
 // Define gotype, for composite ones recurse into constituents.
 static DWDie*
-defgotype(Sym *gotype)
+defgotype(LSym *gotype)
 {
 	DWDie *die, *fld;
-	Sym *s;
+	LSym *s;
 	char *name, *f;
 	uint8 kind;
 	vlong bytesize;
@@ -1335,7 +1335,7 @@ synthesizechantypes(DWDie *die)
 
 // For use with pass.c::genasmsym
 static void
-defdwsymb(Sym* sym, char *s, int t, vlong v, vlong size, int ver, Sym *gotype)
+defdwsymb(LSym* sym, char *s, int t, vlong v, vlong size, int ver, LSym *gotype)
 {
 	DWDie *dv, *dt;
 
@@ -1607,7 +1607,7 @@ inithist(Auto *a)
 			absline = a->aoffset;
 		} else if (a->type == D_FILE1) {  // 'Z'
 			// We could just fixup the current
-			// linehist->line, but there doesn't appear to
+			// linehist->lineno, but there doesn't appear to
 			// be a guarantee that every 'Z' is preceded
 			// by its own 'z', so do the safe thing and
 			// update the stack and push a new Linehist
@@ -1719,7 +1719,7 @@ mkvarname(char* name, int da)
 
 // flush previous compilation unit.
 static void
-flushunit(DWDie *dwinfo, vlong pc, Sym *pcsym, vlong unitstart, int32 header_length)
+flushunit(DWDie *dwinfo, vlong pc, LSym *pcsym, vlong unitstart, int32 header_length)
 {
 	vlong here;
 
@@ -1745,7 +1745,7 @@ static void
 writelines(void)
 {
 	Prog *q;
-	Sym *s, *epcs;
+	LSym *s, *epcs;
 	Auto *a;
 	vlong unitstart, headerend, offs;
 	vlong pc, epc, lc, llc, lline;
@@ -1757,7 +1757,7 @@ writelines(void)
 	char *n, *nn;
 
 	if(linesec == S)
-		linesec = lookup(".dwarfline", 0);
+		linesec = linklookup(ctxt, ".dwarfline", 0);
 	linesec->nr = 0;
 
 	unitstart = -1;
@@ -1771,8 +1771,8 @@ writelines(void)
 	lineo = cpos();
 	dwinfo = nil;
 
-	for(cursym = textp; cursym != nil; cursym = cursym->next) {
-		s = cursym;
+	for(ctxt->cursym = ctxt->textp; ctxt->cursym != nil; ctxt->cursym = ctxt->cursym->next) {
+		s = ctxt->cursym;
 		if(s->text == P)
 			continue;
 
@@ -1859,7 +1859,7 @@ writelines(void)
 			continue;
 
 		for(q = s->text; q != P; q = q->link) {
-			lh = searchhist(q->line);
+			lh = searchhist(q->lineno);
 			if (lh == nil) {
 				diag("dwarf: corrupt history or bad absolute line: %P", q);
 				continue;
@@ -1870,11 +1870,11 @@ writelines(void)
 				continue;
 			}
 
-			lline = lh->line + q->line - lh->absline;
+			lline = lh->line + q->lineno - lh->absline;
 			if (debug['v'] > 1)
 				print("%6llux %s[%lld] %P\n", (vlong)q->pc, histfile[lh->file], lline, q);
 
-			if (q->line == lc)
+			if (q->lineno == lc)
 				continue;
 			if (currfile != lh->file) {
 				currfile = lh->file;
@@ -1883,7 +1883,7 @@ writelines(void)
 			}
 			putpclcdelta(q->pc - pc, lline - llc);
 			pc  = q->pc;
-			lc  = q->line;
+			lc  = q->lineno;
 			llc = lline;
 		}
 
@@ -1971,11 +1971,11 @@ static void
 writeframes(void)
 {
 	Prog *p, *q;
-	Sym *s;
+	LSym *s;
 	vlong fdeo, fdesize, pad, cfa, pc;
 
 	if(framesec == S)
-		framesec = lookup(".dwarfframe", 0);
+		framesec = linklookup(ctxt, ".dwarfframe", 0);
 	framesec->nr = 0;
 	frameo = cpos();
 
@@ -2003,8 +2003,8 @@ writeframes(void)
 	}
 	strnput("", pad);
 
-	for(cursym = textp; cursym != nil; cursym = cursym->next) {
-		s = cursym;
+	for(ctxt->cursym = ctxt->textp; ctxt->cursym != nil; ctxt->cursym = ctxt->cursym->next) {
+		s = ctxt->cursym;
 		if(s->text == nil)
 			continue;
 
@@ -2067,11 +2067,11 @@ writeinfo(void)
 
 	fwdcount = 0;
 	if (infosec == S)
-		infosec = lookup(".dwarfinfo", 0);
+		infosec = linklookup(ctxt, ".dwarfinfo", 0);
 	infosec->nr = 0;
 
 	if(arangessec == S)
-		arangessec = lookup(".dwarfaranges", 0);
+		arangessec = linklookup(ctxt, ".dwarfaranges", 0);
 	arangessec->nr = 0;
 
 	for (compunit = dwroot.child; compunit; compunit = compunit->link) {
@@ -2204,7 +2204,7 @@ writearanges(void)
 		strnput("", headersize - (4+2+4+1+1));	// align to PtrSize
 
 		if(linkmode == LinkExternal)
-			adddwarfrel(arangessec, (Sym*)b->data, sectionstart, PtrSize, b->value-((Sym*)b->data)->value);
+			adddwarfrel(arangessec, (LSym*)b->data, sectionstart, PtrSize, b->value-((LSym*)b->data)->value);
 		else
 			addrput(b->value);
 
@@ -2239,7 +2239,7 @@ align(vlong size)
 }
 
 static vlong
-writedwarfreloc(Sym* s)
+writedwarfreloc(LSym* s)
 {
 	int i;
 	vlong start;
@@ -2408,7 +2408,7 @@ enum
 vlong elfstrdbg[NElfStrDbg];
 
 void
-dwarfaddshstrings(Sym *shstrtab)
+dwarfaddshstrings(LSym *shstrtab)
 {
 	if(debug['w'])  // disable dwarf
 		return;
@@ -2438,16 +2438,16 @@ dwarfaddshstrings(Sym *shstrtab)
 			elfstrdbg[ElfStrRelDebugFrame] = addstring(shstrtab, ".rel.debug_frame");
 		}
 
-		infosym = lookup(".debug_info", 0);
+		infosym = linklookup(ctxt, ".debug_info", 0);
 		infosym->hide = 1;
 
-		abbrevsym = lookup(".debug_abbrev", 0);
+		abbrevsym = linklookup(ctxt, ".debug_abbrev", 0);
 		abbrevsym->hide = 1;
 
-		linesym = lookup(".debug_line", 0);
+		linesym = linklookup(ctxt, ".debug_line", 0);
 		linesym->hide = 1;
 
-		framesym = lookup(".debug_frame", 0);
+		framesym = linklookup(ctxt, ".debug_frame", 0);
 		framesym->hide = 1;
 	}
 }