From 06640d93e010b7dc6dc8a70621c2e5028686be89 Mon Sep 17 00:00:00 2001
From: Juergen Ributzka <juergen@apple.com>
Date: Fri, 25 Jul 2014 17:47:14 +0000
Subject: [PATCH] [FastISel][AArch64] Add support for frameaddress intrinsic.

This commit implements the frameaddress intrinsic for the AArch64 architecture
in FastISel.

There were two test cases that pretty much tested the same, so I combined them
to a single test case.

Fixes <rdar://problem/17811834>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213959 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/AArch64/AArch64FastISel.cpp  | 30 ++++++++++++++++++++++++++++--
 test/CodeGen/AArch64/arm64-frameaddr.ll | 15 ---------------
 test/CodeGen/AArch64/frameaddr.ll       | 29 +++++++++++++++++++----------
 3 files changed, 47 insertions(+), 27 deletions(-)
 delete mode 100644 test/CodeGen/AArch64/arm64-frameaddr.ll

diff --git a/lib/Target/AArch64/AArch64FastISel.cpp b/lib/Target/AArch64/AArch64FastISel.cpp
index 8f4fac9a56b..13312433e2d 100644
--- a/lib/Target/AArch64/AArch64FastISel.cpp
+++ b/lib/Target/AArch64/AArch64FastISel.cpp
@@ -1438,8 +1438,34 @@ bool AArch64FastISel::TryEmitSmallMemCpy(Address Dest, Address Src,
 bool AArch64FastISel::FastLowerIntrinsicCall(const IntrinsicInst *II) {
   // FIXME: Handle more intrinsics.
   switch (II->getIntrinsicID()) {
-  default:
-    return false;
+  default: return false;
+  case Intrinsic::frameaddress: {
+    MachineFrameInfo *MFI = FuncInfo.MF->getFrameInfo();
+    MFI->setFrameAddressIsTaken(true);
+
+    const AArch64RegisterInfo *RegInfo =
+      static_cast<const AArch64RegisterInfo *>(TM.getRegisterInfo());
+    unsigned FramePtr = RegInfo->getFrameRegister(*(FuncInfo.MF));
+    unsigned SrcReg = FramePtr;
+
+    // Recursively load frame address
+    // ldr x0, [fp]
+    // ldr x0, [x0]
+    // ldr x0, [x0]
+    // ...
+    unsigned DestReg;
+    unsigned Depth = cast<ConstantInt>(II->getOperand(0))->getZExtValue();
+    while (Depth--) {
+      DestReg = createResultReg(&AArch64::GPR64RegClass);
+      BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
+              TII.get(AArch64::LDRXui), DestReg)
+        .addReg(SrcReg).addImm(0);
+      SrcReg = DestReg;
+    }
+
+    UpdateValueMap(II, SrcReg);
+    return true;
+  }
   case Intrinsic::memcpy:
   case Intrinsic::memmove: {
     const auto *MTI = cast<MemTransferInst>(II);
diff --git a/test/CodeGen/AArch64/arm64-frameaddr.ll b/test/CodeGen/AArch64/arm64-frameaddr.ll
deleted file mode 100644
index 469078c8814..00000000000
--- a/test/CodeGen/AArch64/arm64-frameaddr.ll
+++ /dev/null
@@ -1,15 +0,0 @@
-; RUN: llc < %s -march=arm64 | FileCheck %s
-
-define i8* @t() nounwind {
-entry:
-; CHECK-LABEL: t:
-; CHECK: stp x29, x30, [sp, #-16]!
-; CHECK: mov x29, sp
-; CHECK: mov x0, x29
-; CHECK: ldp x29, x30, [sp], #16
-; CHECK: ret
-	%0 = call i8* @llvm.frameaddress(i32 0)
-        ret i8* %0
-}
-
-declare i8* @llvm.frameaddress(i32) nounwind readnone
diff --git a/test/CodeGen/AArch64/frameaddr.ll b/test/CodeGen/AArch64/frameaddr.ll
index 85d95e21c9b..ff9916c156b 100644
--- a/test/CodeGen/AArch64/frameaddr.ll
+++ b/test/CodeGen/AArch64/frameaddr.ll
@@ -1,20 +1,29 @@
-; RUN: llc -o - %s -mtriple=arm64-apple-ios7.0  | FileCheck %s
+; RUN: llc -mtriple=arm64-apple-ios7.0                             < %s | FileCheck %s
+; RUN: llc -mtriple=arm64-apple-ios7.0 -fast-isel -fast-isel-abort < %s | FileCheck %s
 
-define i8* @t() nounwind {
+define i8* @test_frameaddress0() nounwind {
 entry:
-; CHECK-LABEL: t:
+; CHECK-LABEL: test_frameaddress0:
+; CHECK: stp x29, x30, [sp, #-16]!
+; CHECK: mov x29, sp
 ; CHECK: mov x0, x29
-	%0 = call i8* @llvm.frameaddress(i32 0)
-        ret i8* %0
+; CHECK: ldp x29, x30, [sp], #16
+; CHECK: ret
+  %0 = call i8* @llvm.frameaddress(i32 0)
+  ret i8* %0
 }
 
-define i8* @t2() nounwind {
+define i8* @test_frameaddress2() nounwind {
 entry:
-; CHECK-LABEL: t2:
+; CHECK-LABEL: test_frameaddress2:
+; CHECK: stp x29, x30, [sp, #-16]!
+; CHECK: mov x29, sp
 ; CHECK: ldr x[[reg:[0-9]+]], [x29]
-; CHECK: ldr {{x[0-9]+}}, [x[[reg]]]
-	%0 = call i8* @llvm.frameaddress(i32 2)
-        ret i8* %0
+; CHECK: ldr x0, [x[[reg]]]
+; CHECK: ldp x29, x30, [sp], #16
+; CHECK: ret
+  %0 = call i8* @llvm.frameaddress(i32 2)
+  ret i8* %0
 }
 
 declare i8* @llvm.frameaddress(i32) nounwind readnone
-- 
2.11.0