cmd/link: fix up more zero-sized local symbols on darwin dynamic linking

When dynamic linking on darwin, the darwin linker doesn't link
relocations pointing to zero-sized local symbols, like our
start/end marker symbols, e.g. runtime.text and runtime.etext.
It will choose to resolve to another symbol on the same address
that may not be local, therefore that reference may point to a
different DSO, which is not what we want. We already fix up some
marker symbols, like text/etext, data/edata, bss/ebss. But we
currently don't fix up noptrdata and noptrbss. With the new
darwin linker ld-prime, this causes problems when building a
plugin. Fix up those symbols.

For #61229.

Change-Id: I2181bb9184b85af9a3c3f5dc6d78e4d5a1d56d53
Reviewed-on: https://go-review.googlesource.com/c/go/+/503538
Reviewed-by: Than McIntosh <thanm@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

1 files changed, 19 insertions, 3 deletions

diff --git a/src/cmd/link/internal/ld/data.go b/src/cmd/link/internal/ld/data.go
index 95fc8b5a42..a9f10af5af 100644
--- a/src/cmd/link/internal/ld/data.go
+++ b/src/cmd/link/internal/ld/data.go
@@ -1075,7 +1075,7 @@ func writeBlock(ctxt *Link, out *OutBuf, ldr *loader.Loader, syms []loader.Sym,
 			break
 		}
 		if val < addr {
-			ldr.Errorf(s, "phase error: addr=%#x but sym=%#x type=%v sect=%v", addr, val, ldr.SymType(s), ldr.SymSect(s).Name)
+			ldr.Errorf(s, "phase error: addr=%#x but val=%#x sym=%s type=%v sect=%v sect.addr=%#x", addr, val, ldr.SymName(s), ldr.SymType(s), ldr.SymSect(s).Name, ldr.SymSect(s).Vaddr)
 			errorexit()
 		}
 		if addr < val {
@@ -1426,6 +1426,20 @@ func fixZeroSizedSymbols(ctxt *Link) {
 		edata.SetType(sym.SXCOFFTOC)
 	}
 
+	noptrbss := ldr.CreateSymForUpdate("runtime.noptrbss", 0)
+	noptrbss.SetSize(8)
+	ldr.SetAttrSpecial(noptrbss.Sym(), false)
+
+	enoptrbss := ldr.CreateSymForUpdate("runtime.enoptrbss", 0)
+	ldr.SetAttrSpecial(enoptrbss.Sym(), false)
+
+	noptrdata := ldr.CreateSymForUpdate("runtime.noptrdata", 0)
+	noptrdata.SetSize(8)
+	ldr.SetAttrSpecial(noptrdata.Sym(), false)
+
+	enoptrdata := ldr.CreateSymForUpdate("runtime.enoptrdata", 0)
+	ldr.SetAttrSpecial(enoptrdata.Sym(), false)
+
 	types := ldr.CreateSymForUpdate("runtime.types", 0)
 	types.SetType(sym.STYPE)
 	types.SetSize(8)
@@ -2234,10 +2248,12 @@ func (state *dodataState) dodataSect(ctxt *Link, symn sym.SymKind, syms []loader
 		// end of their section.
 		if (ctxt.DynlinkingGo() && ctxt.HeadType == objabi.Hdarwin) || (ctxt.HeadType == objabi.Haix && ctxt.LinkMode == LinkExternal) {
 			switch ldr.SymName(s) {
-			case "runtime.text", "runtime.bss", "runtime.data", "runtime.types", "runtime.rodata":
+			case "runtime.text", "runtime.bss", "runtime.data", "runtime.types", "runtime.rodata",
+				"runtime.noptrdata", "runtime.noptrbss":
 				head = s
 				continue
-			case "runtime.etext", "runtime.ebss", "runtime.edata", "runtime.etypes", "runtime.erodata":
+			case "runtime.etext", "runtime.ebss", "runtime.edata", "runtime.etypes", "runtime.erodata",
+				"runtime.enoptrdata", "runtime.enoptrbss":
 				tail = s
 				continue
 			}