Add test for a BTI landing pad target in execute-only thunks

Author: Il-Capitano

lld/test/ELF/aarch64-thunk-bti-execute-only.s

@@ -0,0 +1,75 @@
+// REQUIRES: aarch64
+// RUN: rm -rf %t && split-file %s %t && cd %t
+// RUN: llvm-mc -filetype=obj -triple=aarch64 asm -o a.o
+// RUN: ld.lld --script=lds a.o -o exe --defsym absolute=0xf0000000
+// RUN: llvm-objdump -d --no-show-raw-insn exe | FileCheck %s
+
+//--- asm
+.section ".note.gnu.property", "a"
+.p2align 3
+.long 4
+.long 0x10
+.long 0x5
+.asciz "GNU"
+
+/// Enable BTI.
+.long 0xc0000000 // GNU_PROPERTY_AARCH64_FEATURE_1_AND.
+.long 4
+.long 1          // GNU_PROPERTY_AARCH64_FEATURE_1_BTI.
+.long 0
+
+.section .text.0,"axy",@progbits
+.global _start
+.type _start,@function
+_start:
+/// Expect thunk to target a linker generated entry point with BTI landing pad.
+/// Two calls to make sure only one landing pad is created.
+  bl fn1
+  b  fn1
+/// No BTI landing pad is added for absolute symbols.
+  bl absolute
+
+/// This function does not have a BTI compatible landing pad. Expect a linker
+/// generated landing pad for indirect branch thunks.
+.section .text.1,"axy",@progbits
+.hidden fn1
+.type fn1,@function
+fn1:
+  ret
+
+// CHECK-LABEL: <_start>:
+// CHECK-NEXT:  18001000: bl      0x1800100c <__AArch64AbsXOLongThunk_>
+// CHECK-NEXT:            b       0x1800100c <__AArch64AbsXOLongThunk_>
+// CHECK-NEXT:            bl      0x18001020 <__AArch64AbsXOLongThunk_absolute>
+
+// CHECK-LABEL: <__AArch64AbsXOLongThunk_>:
+// CHECK-NEXT:  1800100c: mov     x16, #0x0
+// CHECK-NEXT:            movk    x16, #0x3000, lsl #16
+// CHECK-NEXT:            movk    x16, #0x0, lsl #32
+// CHECK-NEXT:            movk    x16, #0x0, lsl #48
+// CHECK-NEXT:            br      x16
+
+// CHECK-LABEL: <__AArch64AbsXOLongThunk_absolute>:
+// CHECK-NEXT:  18001020: mov     x16, #0x0
+// CHECK-NEXT:            movk    x16, #0xf000, lsl #16
+// CHECK-NEXT:            movk    x16, #0x0, lsl #32
+// CHECK-NEXT:            movk    x16, #0x0, lsl #48
+// CHECK-NEXT:            br      x16
+
+// CHECK-LABEL: <__AArch64BTIThunk_>:
+// CHECK-NEXT:  30000000: bti     c
+
+// CHECK-LABEL: <fn1>:
+// CHECK-NEXT:  30000004: ret
+
+//--- lds
+PHDRS {
+  low PT_LOAD FLAGS(0x1 | 0x4);
+  mid PT_LOAD FLAGS(0x1 | 0x4);
+  high PT_LOAD FLAGS(0x1 | 0x4);
+}
+SECTIONS {
+  .rodata 0x10000000 : { *(.note.gnu.property) } :low
+  .text 0x18001000 : { *(.text.0) } :mid
+  .text_high 0x30000000 : { *(.text.*) } :high
+}