cmd/link: on PPC64, put plt stubs at beginning of Textp

Put call stubs at the beginning (instead of the end). So the trampoline pass knows the addresses of the stubs, and it can insert trampolines when necessary. Fixes golang#19425. Change-Id: I1e06529ef837a6130df58917315610d45a6819ca Reviewed-on: https://go-review.googlesource.com/38131 Run-TryBot: Cherry Zhang <cherryyz@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
amazingandyyy · Mar 15, 2017 · 15b3765 · 15b3765
1 parent 43afcb5
commit 15b3765
Showing 1 changed file with 7 additions and 1 deletion.
diff --git a/src/cmd/link/internal/ppc64/asm.go b/src/cmd/link/internal/ppc64/asm.go
@@ -87,6 +87,7 @@ func genplt(ctxt *ld.Link) {
 	//
 	// This assumes "case 1" from the ABI, where the caller needs
 	// us to save and restore the TOC pointer.
+	var stubs []*ld.Symbol
 	for _, s := range ctxt.Textp {
 		for i := range s.R {
 			r := &s.R[i]
@@ -108,7 +109,7 @@ func genplt(ctxt *ld.Link) {
 			if stub.Size == 0 {
 				// Need outer to resolve .TOC.
 				stub.Outer = s
-				ctxt.Textp = append(ctxt.Textp, stub)
+				stubs = append(stubs, stub)
 				gencallstub(ctxt, 1, stub, r.Sym)
 			}
 
@@ -121,6 +122,11 @@ func genplt(ctxt *ld.Link) {
 			ctxt.Arch.ByteOrder.PutUint32(s.P[r.Off+4:], o1)
 		}
 	}
+	// Put call stubs at the beginning (instead of the end).
+	// So when resolving the relocations to calls to the stubs,
+	// the addresses are known and trampolines can be inserted
+	// when necessary.
+	ctxt.Textp = append(stubs, ctxt.Textp...)
 }
 
 func genaddmoduledata(ctxt *ld.Link) {