123 lines
3.9 KiB
Diff
123 lines
3.9 KiB
Diff
diff --git a/src/cmd/go/testdata/script/trampoline_reuse_test.txt b/src/cmd/go/testdata/script/trampoline_reuse_test.txt
|
|
new file mode 100644
|
|
index 0000000000000..bca897c16d054
|
|
--- /dev/null
|
|
+++ b/src/cmd/go/testdata/script/trampoline_reuse_test.txt
|
|
@@ -0,0 +1,100 @@
|
|
+# Verify PPC64 does not reuse a trampoline which is too far away.
|
|
+# This tests an edge case where the direct call relocation addend should
|
|
+# be ignored when computing the distance from the direct call to the
|
|
+# already placed trampoline
|
|
+[short] skip
|
|
+[!ppc64] [!ppc64le] skip
|
|
+[aix] skip
|
|
+
|
|
+# Note, this program does not run. Presumably, 'DWORD $0' is simpler to
|
|
+# assembly 2^26 or so times.
|
|
+#
|
|
+# We build something which should be laid out as such:
|
|
+#
|
|
+# bar.Bar
|
|
+# main.Func1
|
|
+# bar.Bar+400-tramp0
|
|
+# main.BigAsm
|
|
+# main.Func2
|
|
+# bar.Bar+400-tramp1
|
|
+#
|
|
+# bar.Bar needs to be placed far enough away to generate relocations
|
|
+# from main package calls. and main.Func1 and main.Func2 are placed
|
|
+# a bit more than the direct call limit apart, but not more than 0x400
|
|
+# bytes beyond it (to verify the reloc calc).
|
|
+
|
|
+go build
|
|
+
|
|
+-- go.mod --
|
|
+
|
|
+module foo
|
|
+
|
|
+go 1.19
|
|
+
|
|
+-- main.go --
|
|
+
|
|
+package main
|
|
+
|
|
+import "foo/bar"
|
|
+
|
|
+func Func1()
|
|
+
|
|
+func main() {
|
|
+ Func1()
|
|
+ bar.Bar2()
|
|
+}
|
|
+
|
|
+-- foo.s --
|
|
+
|
|
+TEXT main·Func1(SB),0,$0-0
|
|
+ CALL bar·Bar+0x400(SB)
|
|
+ CALL main·BigAsm(SB)
|
|
+// A trampoline will be placed here to bar.Bar
|
|
+
|
|
+// This creates a gap sufficiently large to prevent trampoline reuse
|
|
+#define NOP64 DWORD $0; DWORD $0; DWORD $0; DWORD $0; DWORD $0; DWORD $0; DWORD $0; DWORD $0;
|
|
+#define NOP256 NOP64 NOP64 NOP64 NOP64
|
|
+#define NOP2S10 NOP256 NOP256 NOP256 NOP256
|
|
+#define NOP2S12 NOP2S10 NOP2S10 NOP2S10 NOP2S10
|
|
+#define NOP2S14 NOP2S12 NOP2S12 NOP2S12 NOP2S12
|
|
+#define NOP2S16 NOP2S14 NOP2S14 NOP2S14 NOP2S14
|
|
+#define NOP2S18 NOP2S16 NOP2S16 NOP2S16 NOP2S16
|
|
+#define NOP2S20 NOP2S18 NOP2S18 NOP2S18 NOP2S18
|
|
+#define NOP2S22 NOP2S20 NOP2S20 NOP2S20 NOP2S20
|
|
+#define NOP2S24 NOP2S22 NOP2S22 NOP2S22 NOP2S22
|
|
+#define BIGNOP NOP2S24 NOP2S24
|
|
+TEXT main·BigAsm(SB),0,$0-0
|
|
+ // Fill to the direct call limit so Func2 must generate a new trampoline.
|
|
+ // As the implicit trampoline above is just barely unreachable.
|
|
+ BIGNOP
|
|
+ MOVD $main·Func2(SB), R3
|
|
+
|
|
+TEXT main·Func2(SB),0,$0-0
|
|
+ CALL bar·Bar+0x400(SB)
|
|
+// Another trampoline should be placed here.
|
|
+
|
|
+-- bar/bar.s --
|
|
+
|
|
+#define NOP64 DWORD $0; DWORD $0; DWORD $0; DWORD $0; DWORD $0; DWORD $0; DWORD $0; DWORD $0;
|
|
+#define NOP256 NOP64 NOP64 NOP64 NOP64
|
|
+#define NOP2S10 NOP256 NOP256 NOP256 NOP256
|
|
+#define NOP2S12 NOP2S10 NOP2S10 NOP2S10 NOP2S10
|
|
+#define NOP2S14 NOP2S12 NOP2S12 NOP2S12 NOP2S12
|
|
+#define NOP2S16 NOP2S14 NOP2S14 NOP2S14 NOP2S14
|
|
+#define NOP2S18 NOP2S16 NOP2S16 NOP2S16 NOP2S16
|
|
+#define NOP2S20 NOP2S18 NOP2S18 NOP2S18 NOP2S18
|
|
+#define NOP2S22 NOP2S20 NOP2S20 NOP2S20 NOP2S20
|
|
+#define NOP2S24 NOP2S22 NOP2S22 NOP2S22 NOP2S22
|
|
+#define BIGNOP NOP2S24 NOP2S24 NOP2S10
|
|
+// A very big not very interesting function.
|
|
+TEXT bar·Bar(SB),0,$0-0
|
|
+ BIGNOP
|
|
+
|
|
+-- bar/bar.go --
|
|
+
|
|
+package bar
|
|
+
|
|
+func Bar()
|
|
+
|
|
+func Bar2() {
|
|
+}
|
|
diff --git a/src/cmd/link/internal/ppc64/asm.go b/src/cmd/link/internal/ppc64/asm.go
|
|
index 5d5fbe2a97735..6313879da083c 100644
|
|
--- a/src/cmd/link/internal/ppc64/asm.go
|
|
+++ b/src/cmd/link/internal/ppc64/asm.go
|
|
@@ -900,8 +900,9 @@ func trampoline(ctxt *ld.Link, ldr *loader.Loader, ri int, rs, s loader.Sym) {
|
|
if ldr.SymValue(tramp) == 0 {
|
|
break
|
|
}
|
|
-
|
|
- t = ldr.SymValue(tramp) + r.Add() - (ldr.SymValue(s) + int64(r.Off()))
|
|
+ // Note, the trampoline is always called directly. The addend of the original relocation is accounted for in the
|
|
+ // trampoline itself.
|
|
+ t = ldr.SymValue(tramp) - (ldr.SymValue(s) + int64(r.Off()))
|
|
|
|
// With internal linking, the trampoline can be used if it is not too far.
|
|
// With external linking, the trampoline must be in this section for it to be reused.
|