FFI step 2: can ask for libc.so.6.

introduced explicit "data" symbol instead of etext
to mark beginning of data, so that using larger
alignment (i.e. 4MB like GNU loader) doesn't
confuse garbage collector.

split dodata into dodata and dobss in preparation
for putting the dynamic data + headers in the data
segment instead of stuffed at the beginning of the binary.

R=r
DELTA=52  (37 added, 3 deleted, 12 changed)
OCL=33610
CL=33618

6 files changed, 46 insertions, 13 deletions

diff --git a/src/cmd/6l/asm.c b/src/cmd/6l/asm.c
index 7e0bd9191d..5acaaae5f1 100644
--- a/src/cmd/6l/asm.c
+++ b/src/cmd/6l/asm.c
@@ -128,7 +128,7 @@ asmb(void)
 	int32 v, magic;
 	int a, nl;
 	uchar *op1;
-	vlong vl, va, startva, fo, w, symo, hashoff;
+	vlong vl, va, startva, fo, w, symo, hashoff, dstrtab, off;
 	vlong symdatva = 0x99LL<<32;
 	Elf64Hdr *eh;
 	Elf64PHdr *ph, *pph;
@@ -431,6 +431,7 @@ asmb(void)
 		sh = newElf64SHdr("");
 
 		pph = nil;	/* silence compiler */
+		dstrtab = 0;
 
 		/* Dynamic linking sections */
 		if (!debug['d']) {	/* -d suppresses dynamic loader format */
@@ -443,7 +444,7 @@ asmb(void)
 			pph->off = ELF64HDRSIZE;
 			pph->vaddr = startva + pph->off;
 			pph->paddr = startva + pph->off;
-			pph->align = 8;
+			pph->align = INITRND;
 
 			/* interpreter */
 			ph = newElf64PHdr();
@@ -503,13 +504,19 @@ asmb(void)
 			sh->addr = startva + sh->off;
 			sh->off = startelf();
 			elf64writedynent(DT_HASH, startva+hashoff);
-			elf64writedynent(DT_STRTAB, startva+ELF64FULLHDRSIZE-STRTABSIZE);
 			elf64writedynent(DT_SYMTAB, startva);
 			elf64writedynent(DT_RELA, startva);
 			elf64writedynent(DT_RELASZ, 0);	// size of the whole rela in bytes
 			elf64writedynent(DT_RELAENT, ELF64RELASIZE);
-			elf64writedynent(DT_STRSZ, STRTABSIZE);
 			elf64writedynent(DT_SYMENT, 0);
+//			elf64writedynent(DT_NEEDED, elf64addstr("libc.so.6"));
+
+			/* make space for these now but fill them in later */
+			cflush();
+			dstrtab = seek(cout, 0, 1);
+			elf64writedynent(DT_STRTAB, -1);
+			elf64writedynent(DT_STRSZ, -1);
+
 			elf64writedynent(DT_NULL, 0);
 			sh->size = endelf() - sh->off;
 			sh->addralign = 8;
@@ -534,7 +541,7 @@ asmb(void)
 			ph->paddr = startva + ph->off;
 			ph->filesz = sh->off + sh->size - ph->off;
 			ph->memsz = ph->filesz;
-			ph->align = 8;
+			ph->align = INITRND;
 		}
 
 		ph = newElf64PHdr();
@@ -644,6 +651,17 @@ asmb(void)
 		elf64writestrtable();
 		sh->size = endelf() - sh->off;
 
+		if(dstrtab != 0) {
+			// update DT_STRTAB entry
+			cflush();
+			off = seek(cout, 0, 1);
+			seek(cout, dstrtab, 0);
+			elf64writedynent(DT_STRTAB, sh->addr);
+			elf64writedynent(DT_STRSZ, sh->size);
+			cflush();
+			seek(cout, off, 0);
+		}
+
 		/* Main header */
 		eh = getElf64Hdr();
 		eh->ident[EI_MAG0] = '\177';
diff --git a/src/cmd/6l/l.h b/src/cmd/6l/l.h
index 8f72812bcc..0490bc1db1 100644
--- a/src/cmd/6l/l.h
+++ b/src/cmd/6l/l.h
@@ -390,6 +390,7 @@ double	cputime(void);
 void	datblk(int32, int32);
 void	deadcode(void);
 void	diag(char*, ...);
+void	dobss(void);
 void	dodata(void);
 void	doinit(void);
 void	doprof1(void);
diff --git a/src/cmd/6l/obj.c b/src/cmd/6l/obj.c
index d9630fe333..98318d94b1 100644
--- a/src/cmd/6l/obj.c
+++ b/src/cmd/6l/obj.c
@@ -390,6 +390,7 @@ main(int argc, char *argv[])
 	patch();
 	follow();
 	dodata();
+	dobss();
 	dostkoff();
 	paramspace = "SP";	/* (FP) now (SP) on output */
 	if(debug['p'])
diff --git a/src/cmd/6l/pass.c b/src/cmd/6l/pass.c
index 3917ac5423..540063568f 100644
--- a/src/cmd/6l/pass.c
+++ b/src/cmd/6l/pass.c
@@ -124,6 +124,14 @@ dodata(void)
 		}
 		datsize += u;
 	}
+}
+
+void
+dobss(void)
+{
+	int i;
+	Sym *s;
+	int32 t;
 
 	/* now the bss */
 	bsssize = 0;
@@ -137,6 +145,7 @@ dodata(void)
 		s->value = bsssize + datsize;
 		bsssize += t;
 	}
+	xdefine("data", SBSS, 0);
 	xdefine("edata", SBSS, datsize);
 	xdefine("end", SBSS, bsssize + datsize);
 }
diff --git a/src/cmd/ld/elf64.c b/src/cmd/ld/elf64.c
index dc9f4196b1..d6a2f7f3c2 100644
--- a/src/cmd/ld/elf64.c
+++ b/src/cmd/ld/elf64.c
@@ -13,7 +13,7 @@ static	Elf64Hdr	hdr;
 static	Elf64PHdr	*phdr[NSECT];
 static	Elf64SHdr	*shdr[NSECT];
 static	char	*sname[NSECT];
-static	char	*str[NSECT];
+static	char	*str[20];
 
 /*
  Initialize the global variable that describes the ELF header. It will be updated as
@@ -80,15 +80,19 @@ elf64writestrtable(void)
 		diag("elf64 string table overflow");
 }
 
-void
-e64addstr(char *name)
+uint32
+elf64addstr(char *name)
 {
-	if (numstr >= NSECT) {
+	int r;
+
+	if (numstr >= nelem(str)) {
 		diag("too many elf strings");
-		return;
+		return 0;
 	}
 	str[numstr++] = strdup(name);
+	r = stroffset;
 	stroffset += strlen(name)+1;
+	return r;
 }
 
 uint32
@@ -135,11 +139,10 @@ newElf64SHdr(char *name)
 		hdr.shstrndx = hdr.shnum;
 	e = malloc(sizeof *e);
 	memset(e, 0, sizeof *e);
-	e->name = stroffset;
+	e->name = elf64addstr(name);
 	if (hdr.shnum >= NSECT) {
 		diag("too many shdrs");
 	} else {
-		e64addstr(name);
 		shdr[hdr.shnum++] = e;
 	}
 	return e;
@@ -152,7 +155,7 @@ getElf64Hdr(void)
 }
 
 uint32
-elf64writehdr()
+elf64writehdr(void)
 {
 	int i;
 
diff --git a/src/cmd/ld/elf64.h b/src/cmd/ld/elf64.h
index 55d0ca3098..bde6376783 100644
--- a/src/cmd/ld/elf64.h
+++ b/src/cmd/ld/elf64.h
@@ -274,6 +274,7 @@ Elf64PHdr	*newElf64PHdr();
 uint32	elf64writehdr(void);
 uint32	elf64writephdrs(void);
 uint32	elf64writeshdrs(void);
+uint32	elf64addstr(char*);
 void	elf64writestrtable(void);
 void	elf64writedynent(int, uint64);
 uint32	elf64_hash(uchar*);