riscv: Add codegen test for global stack canary

Make sure the code generated for a global stack guard canary
references __stack_chk_guard before and after intervening function
code.

Signed-off-by: Keith Packard <[email protected]>

Author: keith-packard

llvm/test/CodeGen/RISCV/stack-guard-global.ll

@@ -0,0 +1,47 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc -mtriple=riscv64 -verify-machineinstrs < %s \
+; RUN:     | FileCheck %s
+
+define void @foo(i64 %t) sspstrong {
+; CHECK-LABEL: foo:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    addi sp, sp, -32
+; CHECK-NEXT:    .cfi_def_cfa_offset 32
+; CHECK-NEXT:    sd ra, 24(sp) # 8-byte Folded Spill
+; CHECK-NEXT:    sd s0, 16(sp) # 8-byte Folded Spill
+; CHECK-NEXT:    sd s1, 8(sp) # 8-byte Folded Spill
+; CHECK-NEXT:    .cfi_offset ra, -8
+; CHECK-NEXT:    .cfi_offset s0, -16
+; CHECK-NEXT:    .cfi_offset s1, -24
+; CHECK-NEXT:    addi s0, sp, 32
+; CHECK-NEXT:    .cfi_def_cfa s0, 0
+; CHECK-NEXT:    lui s1, %hi(__stack_chk_guard)
+; CHECK-NEXT:    ld a1, %lo(__stack_chk_guard)(s1)
+; CHECK-NEXT:    sd a1, -32(s0)
+; CHECK-NEXT:    slli a0, a0, 2
+; CHECK-NEXT:    addi a0, a0, 15
+; CHECK-NEXT:    andi a0, a0, -16
+; CHECK-NEXT:    sub a0, sp, a0
+; CHECK-NEXT:    mv sp, a0
+; CHECK-NEXT:    call baz
+; CHECK-NEXT:    ld a0, %lo(__stack_chk_guard)(s1)
+; CHECK-NEXT:    ld a1, -32(s0)
+; CHECK-NEXT:    bne a0, a1, .LBB0_2
+; CHECK-NEXT:  # %bb.1:
+; CHECK-NEXT:    addi sp, s0, -32
+; CHECK-NEXT:    ld ra, 24(sp) # 8-byte Folded Reload
+; CHECK-NEXT:    ld s0, 16(sp) # 8-byte Folded Reload
+; CHECK-NEXT:    ld s1, 8(sp) # 8-byte Folded Reload
+; CHECK-NEXT:    addi sp, sp, 32
+; CHECK-NEXT:    ret
+; CHECK-NEXT:  .LBB0_2:
+; CHECK-NEXT:    call __stack_chk_fail
+  %vla = alloca i32, i64 %t, align 4
+  call void @baz(ptr %vla)
+  ret void
+}
+
+declare void @baz(ptr)
+
+!llvm.module.flags = !{!1}
+!1 = !{i32 2, !"stack-protector-guard", !"global"}