[AsmPrinterDwarf] Add support for .cfi_restore directive

As of today we only use .cfi_offset to specify the offset of a CSR, but
we never use .cfi_restore when the CSR is restored.

If we want to perform a more advanced type of shrink-wrapping, we need
to use .cfi_restore in order to switch the CFI state between blocks.

This patch only aims at adding support for the directive.

Differential Revision: https://reviews.llvm.org/D36114

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@317199 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 59 insertions, 31 deletions

diff --git a/test/CodeGen/MIR/AArch64/cfi-def-cfa.mir b/test/CodeGen/MIR/AArch64/cfi-def-cfa.mir
deleted file mode 100644
index a946b9f9f4a..00000000000
--- a/test/CodeGen/MIR/AArch64/cfi-def-cfa.mir
+++ /dev/null
@@ -1,31 +0,0 @@
-# RUN: llc -mtriple=aarch64-none-linux-gnu -run-pass none -o - %s | FileCheck %s
-# This test ensures that the MIR parser parses the def_cfa operands
-# correctly.
-
---- |
-
-  declare void @foo()
-
-  define void @trivial_fp_func() {
-  entry:
-    call void @foo()
-    ret void
-  }
-
-...
----
-name:            trivial_fp_func
-body: |
-  bb.0.entry:
-    liveins: %lr, %fp, %lr, %fp
-
-    %sp = frame-setup STPXpre killed %fp, killed %lr, %sp, -2
-    %fp = frame-setup ADDXri %sp, 0, 0
-    ; CHECK: CFI_INSTRUCTION def_cfa %w29, 16
-    frame-setup CFI_INSTRUCTION def_cfa %w29, 16
-    frame-setup CFI_INSTRUCTION offset %w30, -8
-    frame-setup CFI_INSTRUCTION offset %w29, -16
-    BL @foo, csr_aarch64_aapcs, implicit-def dead %lr, implicit %sp, implicit-def %sp
-    %sp, %fp, %lr = LDPXpost %sp, 2
-    RET_ReallyLR
-...
diff --git a/test/CodeGen/MIR/AArch64/cfi.mir b/test/CodeGen/MIR/AArch64/cfi.mir
new file mode 100644
index 00000000000..8d9a2772afa
--- /dev/null
+++ b/test/CodeGen/MIR/AArch64/cfi.mir
@@ -0,0 +1,59 @@
+# RUN: llc -mtriple=aarch64-none-linux-gnu -run-pass none -o - %s | FileCheck %s
+# This test ensures that the MIR parser parses the cfi directives correctly.
+
+--- |
+
+  declare void @foo()
+
+  define void @trivial_fp_func() {
+  entry:
+    call void @foo()
+    ret void
+  }
+
+  define void @trivial_fp_func_restore() {
+  entry:
+    call void @foo()
+    ret void
+  }
+
+...
+---
+name:            trivial_fp_func
+# CHECK-LABEL: name: trivial_fp_func
+body: |
+  bb.0.entry:
+    liveins: %lr, %fp, %lr, %fp
+
+    %sp = frame-setup STPXpre killed %fp, killed %lr, %sp, -2
+    %fp = frame-setup ADDXri %sp, 0, 0
+    ; CHECK: CFI_INSTRUCTION def_cfa %w29, 16
+    frame-setup CFI_INSTRUCTION def_cfa %w29, 16
+    frame-setup CFI_INSTRUCTION offset %w30, -8
+    frame-setup CFI_INSTRUCTION offset %w29, -16
+    BL @foo, csr_aarch64_aapcs, implicit-def dead %lr, implicit %sp, implicit-def %sp
+    %sp, %fp, %lr = LDPXpost %sp, 2
+    RET_ReallyLR
+...
+---
+name:            trivial_fp_func_restore
+# CHECK-LABEL: name: trivial_fp_func_restore
+body: |
+  bb.0.entry:
+    liveins: %lr, %fp
+
+    %sp = frame-setup STPXpre killed %fp, killed %lr, %sp, -2
+    %fp = frame-setup ADDXri %sp, 0, 0
+    frame-setup CFI_INSTRUCTION def_cfa %w29, 16
+    frame-setup CFI_INSTRUCTION offset %w30, -8
+    ; CHECK: CFI_INSTRUCTION offset %w30, -8
+    frame-setup CFI_INSTRUCTION offset %w29, -16
+    ; CHECK: CFI_INSTRUCTION offset %w29, -16
+    BL @foo, csr_aarch64_aapcs, implicit-def dead %lr, implicit %sp, implicit-def %sp
+    %sp, %fp, %lr = LDPXpost %sp, 2
+    CFI_INSTRUCTION restore %w30
+    ; CHECK: CFI_INSTRUCTION restore %w30
+    CFI_INSTRUCTION restore %w29
+    ; CHECK: CFI_INSTRUCTION restore %w29
+    RET_ReallyLR
+...