From: limeidan <limeidan@loongson.cn>
Date: Mon, 24 Nov 2025 09:28:42 +0000 (+0800)
Subject: cmd/link, cmd/internal/obj: fix a remote call failure issue
X-Git-Tag: go1.26rc1~61
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=d8269ab0d59212fed0f5975f7083f6bbbfc00ec4;p=gostls13.git

cmd/link, cmd/internal/obj: fix a remote call failure issue

When a function call exceeds the immediate value range of the instruction,
a trampoline is required to assist in the jump. Trampoline is only omitted
when plt is needed; otherwise, a check is required.

Change-Id: I7fe2e08d75f6f574475837b560e650bbd4215858
Reviewed-on: https://go-review.googlesource.com/c/go/+/724580
Reviewed-by: abner chenc <chenguoqi@loongson.cn>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: sophie zhao <zhaoxiaolin@loongson.cn>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
---

diff --git a/src/cmd/internal/obj/loong64/asm.go b/src/cmd/internal/obj/loong64/asm.go
index 3fcd6eafd7..f992518015 100644
--- a/src/cmd/internal/obj/loong64/asm.go
+++ b/src/cmd/internal/obj/loong64/asm.go
@@ -2437,6 +2437,9 @@ func (c *ctxt0) asmout(p *obj.Prog, o *Optab, out []uint32) {
 		v := int32(0)
 		if p.To.Target() != nil {
 			v = int32(p.To.Target().Pc-p.Pc) >> 2
+			if v < -1<<25 || v >= 1<<25 {
+				c.ctxt.Diag("branch too far \n%v", p)
+			}
 		}
 		o1 = OP_B_BL(c.opirr(p.As), uint32(v))
 		if p.To.Sym != nil {
diff --git a/src/cmd/link/internal/loong64/asm.go b/src/cmd/link/internal/loong64/asm.go
index 219cfc7196..142578bceb 100644
--- a/src/cmd/link/internal/loong64/asm.go
+++ b/src/cmd/link/internal/loong64/asm.go
@@ -643,11 +643,14 @@ func trampoline(ctxt *ld.Link, ldr *loader.Loader, ri int, rs, s loader.Sym) {
 	relocs := ldr.Relocs(s)
 	r := relocs.At(ri)
 	switch r.Type() {
-	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_LARCH_B26):
-		// Nothing to do.
-		// The plt symbol has not been added. If we add tramp
-		// here, plt will not work.
-	case objabi.R_CALLLOONG64:
+	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_LARCH_B26), objabi.R_CALLLOONG64:
+		if ldr.SymType(rs) == sym.SDYNIMPORT {
+			// Nothing to do.
+			// The plt symbol has not been added. If we add tramp
+			// here, plt will not work.
+			return
+		}
+
 		var t int64
 		// ldr.SymValue(rs) == 0 indicates a cross-package jump to a function that is not yet
 		// laid out. Conservatively use a trampoline. This should be rare, as we lay out packages