all: final merge of NaCl tree

This CL replays the following one CL from the rsc-go13nacl repo.
This is the last replay CL: after this CL the main repo will have
everything the rsc-go13nacl repo did. Changes made to the main
repo after the rsc-go13nacl repo branched off probably mean that
NaCl doesn't actually work after this CL, but all the code is now moved
over and just needs to be redebugged.

---
cmd/6l, cmd/8l, cmd/ld: support for Native Client

See golang.org/s/go13nacl for design overview.

This CL is publicly visible but not CC'ed to golang-dev,
to avoid distracting from the preparation of the Go 1.2
release.

This CL and the others will be checked into my rsc-go13nacl
clone repo for now, and I will send CLs against the main
repo early in the Go 1.3 development.

R≡khr
https://golang.org/cl/15750044
---

LGTM=bradfitz, dave, iant
R=dave, bradfitz, iant
CC=golang-codereviews
https://golang.org/cl/69040044

Author: rsc

include/link.h

@@ -108,6 +108,7 @@ struct	Prog
 	char	ft;	/* 6l, 8l oclass cache */
 	char	tt;	// 6l, 8l
 	uchar	optab;	// 5l
+	uchar	isize;	// 6l, 8l
 
 	char	width;	/* fake for DATA */
 	char	mode;	/* 16, 32, or 64 in 6l, 8l; internal use in 5g, 6g, 8g */
@@ -363,6 +364,9 @@ struct	Link
 	Prog*	blitrl;
 	Prog*	elitrl;
 	int	rexflag;
+	int	rep; // for nacl
+	int	repn; // for nacl
+	int	lock; // for nacl
 	int	asmode;
 	uchar*	andptr;
 	uchar	and[100];
@@ -412,6 +416,7 @@ struct LinkArch
 
 	int	minlc;
 	int	ptrsize;
+	int	regsize;
 
 	// TODO: Give these the same values on all systems.
 	int	D_ADDR;
@@ -447,6 +452,7 @@ enum {
 	Helf,
 	Hfreebsd,
 	Hlinux,
+	Hnacl,
 	Hnetbsd,
 	Hopenbsd,
 	Hplan9,
@@ -563,6 +569,7 @@ extern	char*	anames8[];
 
 extern	LinkArch	link386;
 extern	LinkArch	linkamd64;
+extern	LinkArch	linkamd64p32;
 extern	LinkArch	linkarm;
 
 #pragma	varargck	type	"A"	int

src/cmd/5l/l.h

@@ -39,6 +39,7 @@ enum
 	thechar = '5',
 	PtrSize = 4,
 	IntSize = 4,
+	RegSize = 4,
 	MaxAlign = 8,	// max data alignment
 	FuncAlign = 4  // single-instruction alignment
 };

src/cmd/5l/obj.c

@@ -39,6 +39,11 @@
 char *thestring = "arm";
 LinkArch *thelinkarch = &linkarm;
 
+void
+linkarchinit(void)
+{
+}
+
 void
 archinit(void)
 {
@@ -76,6 +81,7 @@ archinit(void)
 	case Hlinux:	/* arm elf */
 	case Hfreebsd:
 	case Hnetbsd:
+	case Hnacl:
 		debug['d'] = 0;	// with dynamic linking
 		elfinit();
 		HEADR = ELFRESERVE;

src/cmd/6l/asm.c

@@ -661,6 +661,7 @@ asmb(void)
 	case Hsolaris:
 		debug['8'] = 1;	/* 64-bit addresses */
 		break;
+	case Hnacl:
 	case Hwindows:
 		break;
 	}
@@ -689,6 +690,7 @@ asmb(void)
 		case Hopenbsd:
 		case Hdragonfly:
 		case Hsolaris:
+		case Hnacl:
 			symo = rnd(HEADR+segtext.len, INITRND)+rnd(segrodata.len, INITRND)+segdata.filelen;
 			symo = rnd(symo, INITRND);
 			break;
@@ -770,6 +772,7 @@ asmb(void)
 	case Hopenbsd:
 	case Hdragonfly:
 	case Hsolaris:
+	case Hnacl:
 		asmbelf(symo);
 		break;
 	case Hwindows:

src/cmd/6l/l.h

@@ -41,8 +41,6 @@
 enum
 {
 	thechar = '6',
-	PtrSize = 8,
-	IntSize = 8,
 	MaxAlign = 32,	// max data alignment
 
 	// Loop alignment constants:
@@ -64,6 +62,10 @@ enum
 	FuncAlign = 16
 };
 
+EXTERN	int	PtrSize;
+EXTERN	int	IntSize;
+EXTERN	int	RegSize;
+
 #define	P		((Prog*)0)
 #define	S		((LSym*)0)
 #define	TNAME		(ctxt->cursym?ctxt->cursym->name:noname)

src/cmd/6l/obj.c

@@ -41,6 +41,16 @@
 char*	thestring 	= "amd64";
 LinkArch*	thelinkarch = &linkamd64;
 
+void
+linkarchinit(void)
+{
+	if(strcmp(getgoarch(), "amd64p32") == 0)
+		thelinkarch = &linkamd64p32;
+	PtrSize = thelinkarch->ptrsize;
+	IntSize = PtrSize;
+	RegSize = thelinkarch->regsize;
+}
+
 void
 archinit(void)
 {
@@ -63,6 +73,7 @@ archinit(void)
 	case Hdragonfly:
 	case Hfreebsd:
 	case Hlinux:
+	case Hnacl:
 	case Hnetbsd:
 	case Hopenbsd:
 	case Hsolaris:
@@ -117,6 +128,18 @@ archinit(void)
 		if(INITRND == -1)
 			INITRND = 4096;
 		break;
+	case Hnacl:
+		elfinit();
+		debug['w']++; // disable dwarf, which gets confused and is useless anyway
+		HEADR = 0x10000;
+		funcalign = 32;
+		if(INITTEXT == -1)
+			INITTEXT = 0x20000;
+		if(INITDAT == -1)
+			INITDAT = 0;
+		if(INITRND == -1)
+			INITRND = 0x10000;
+		break;
 	case Hwindows:		/* PE executable */
 		peinit();
 		HEADR = PEFILEHEADR;
@@ -128,6 +151,7 @@ archinit(void)
 			INITRND = PESECTALIGN;
 		break;
 	}
+
 	if(INITDAT != 0 && INITRND != 0)
 		print("warning: -D0x%llux is ignored because of -R0x%ux\n",
 			INITDAT, INITRND);

src/cmd/8l/asm.c

@@ -696,6 +696,7 @@ asmb(void)
 	case Hnetbsd:
 	case Hopenbsd:
 	case Hdragonfly:
+	case Hnacl:
 		asmbelf(symo);
 		break;
 	case Hwindows:

src/cmd/8l/l.h

@@ -43,6 +43,7 @@ enum
 	thechar = '8',
 	PtrSize = 4,
 	IntSize = 4,
+	RegSize = 4,
 	MaxAlign = 32,	// max data alignment
 	FuncAlign = 16
 };

src/cmd/8l/obj.c

@@ -41,6 +41,11 @@
 char*	thestring 	= "386";
 LinkArch*	thelinkarch = &link386;
 
+void
+linkarchinit(void)
+{
+}
+
 void
 archinit(void)
 {
@@ -104,6 +109,19 @@ archinit(void)
 		if(INITRND == -1)
 			INITRND = 4096;
 		break;
+	
+	case Hnacl:
+		elfinit();
+		HEADR = 0x10000;
+		funcalign = 32;
+		if(INITTEXT == -1)
+			INITTEXT = 0x20000;
+		if(INITDAT == -1)
+			INITDAT = 0;
+		if(INITRND == -1)
+			INITRND = 0x10000;
+		break;
+	
 	case Hwindows: /* PE executable */
 		peinit();
 		HEADR = PEFILEHEADR;

src/cmd/gc/doc.go

@@ -52,12 +52,14 @@ Flags:
 		add dir1 and dir2 to the list of paths to check for imported packages
 	-N
 		disable optimizations
+	-nolocalimports
+		disallow local (relative) imports
 	-S
 		write assembly language text to standard output (code only)
 	-S -S
 		write assembly language text to standard output (code and data)
 	-u
-		disallow importing packages not marked as safe
+		disallow importing packages not marked as safe; implies -nolocalimports
 	-V
 		print the compiler version
 	-race

src/cmd/ld/data.c

@@ -1047,7 +1047,7 @@ textaddress(void)
 	// Could parallelize, by assigning to text
 	// and then letting threads copy down, but probably not worth it.
 	sect = segtext.sect;
-	sect->align = FuncAlign;
+	sect->align = funcalign;
 	linklookup(ctxt, "text", 0)->sect = sect;
 	linklookup(ctxt, "etext", 0)->sect = sect;
 	va = INITTEXT;
@@ -1058,6 +1058,8 @@ textaddress(void)
 			continue;
 		if(sym->align != 0)
 			va = rnd(va, sym->align);
+		else
+			va = rnd(va, funcalign);
 		sym->value = 0;
 		for(sub = sym; sub != S; sub = sub->sub)
 			sub->value += va;
@@ -1083,13 +1085,14 @@ address(void)
 	segtext.vaddr = va;
 	segtext.fileoff = HEADR;
 	for(s=segtext.sect; s != nil; s=s->next) {
-//print("%s at %#llux + %#llux\n", s->name, va, (vlong)s->len);
 		va = rnd(va, s->align);
 		s->vaddr = va;
 		va += s->len;
 	}
 	segtext.len = va - INITTEXT;
 	segtext.filelen = segtext.len;
+	if(HEADTYPE == Hnacl)
+		va += 32; // room for the "halt sled"
 
 	if(segrodata.sect != nil) {
 		// align to page boundary so as not to mix