cmd/link: improve error for missing SDYNIMPORT support on mips/mips64

Issue an error (instead of crashing) when encountering a symbol that
requires dynamic relocations on mips/mips64. The dynimport support is
in progress, but is not done yet, so rather than crashing, print a
message indicating that the feature is not yet implemented and exit.

Fixes #58240.

Change-Id: I9ad64c89e4f7b4b180964b35ad1d72d375f2df7f
Reviewed-on: https://go-review.googlesource.com/c/go/+/466895
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Joel Sing <[email protected]>
Reviewed-by: David Chase <[email protected]>
Run-TryBot: Than McIntosh <[email protected]>

Author: thanm

src/cmd/link/internal/mips/obj.go

@@ -34,6 +34,7 @@ import (
 	"cmd/internal/objabi"
 	"cmd/internal/sys"
 	"cmd/link/internal/ld"
+	"cmd/link/internal/loader"
 	"internal/buildcfg"
 )
 
@@ -52,6 +53,7 @@ func Init() (*sys.Arch, ld.Arch) {
 		Dwarfregsp: DWARFREGSP,
 		Dwarfreglr: DWARFREGLR,
 
+		Adddynrel:        adddynrel,
 		Archinit:         archinit,
 		Archreloc:        archreloc,
 		Archrelocvariant: archrelocvariant,
@@ -97,3 +99,9 @@ func archinit(ctxt *ld.Link) {
 		}
 	}
 }
+
+func adddynrel(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loader.Sym, r loader.Reloc, rIdx int) bool {
+	ld.Exitf("adddynrel currently unimplemented for MIPS")
+	return false
+
+}

src/cmd/link/internal/mips64/obj.go

@@ -34,6 +34,7 @@ import (
 	"cmd/internal/objabi"
 	"cmd/internal/sys"
 	"cmd/link/internal/ld"
+	"cmd/link/internal/loader"
 	"internal/buildcfg"
 )
 
@@ -51,6 +52,7 @@ func Init() (*sys.Arch, ld.Arch) {
 		Minalign:         minAlign,
 		Dwarfregsp:       dwarfRegSP,
 		Dwarfreglr:       dwarfRegLR,
+		Adddynrel:        adddynrel,
 		Archinit:         archinit,
 		Archreloc:        archreloc,
 		Archrelocvariant: archrelocvariant,
@@ -107,3 +109,9 @@ func archinit(ctxt *ld.Link) {
 		}
 	}
 }
+
+func adddynrel(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loader.Sym, r loader.Reloc, rIdx int) bool {
+	ld.Exitf("adddynrel currently unimplemented for MIPS64")
+	return false
+
+}