From ada759d5fa8a3ecc0e97d88761badfba9193587f Mon Sep 17 00:00:00 2001
From: Chad Rosier <mcrosier@apple.com>
Date: Wed, 30 May 2012 17:23:22 +0000
Subject: [PATCH] [arm-fast-isel] Add support for the llvm.frameaddress()
 intrinsic. Patch by Jush Lu <jush.msn@gmail.com>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157696 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/ARMFastISel.cpp          |  36 +++++++++
 test/CodeGen/ARM/fast-isel-frameaddr.ll | 100 ++++++++++++++++++++++++
 2 files changed, 136 insertions(+)
 create mode 100644 test/CodeGen/ARM/fast-isel-frameaddr.ll

diff --git a/lib/Target/ARM/ARMFastISel.cpp b/lib/Target/ARM/ARMFastISel.cpp
index c13f283a847..2d2d401dceb 100644
--- a/lib/Target/ARM/ARMFastISel.cpp
+++ b/lib/Target/ARM/ARMFastISel.cpp
@@ -2406,6 +2406,42 @@ bool ARMFastISel::SelectIntrinsicCall(const IntrinsicInst &I) {
   // FIXME: Handle more intrinsics.
   switch (I.getIntrinsicID()) {
   default: return false;
+  case Intrinsic::frameaddress: {
+    MachineFrameInfo *MFI = FuncInfo.MF->getFrameInfo();
+    MFI->setFrameAddressIsTaken(true);
+
+    unsigned LdrOpc;
+    const TargetRegisterClass *RC;
+    if (isThumb2) {
+      LdrOpc =  ARM::t2LDRi12;
+      RC = (const TargetRegisterClass*)&ARM::tGPRRegClass;
+    } else {
+      LdrOpc =  ARM::LDRi12;
+      RC = (const TargetRegisterClass*)&ARM::GPRRegClass;
+    }
+
+    const ARMBaseRegisterInfo *RegInfo =
+          static_cast<const ARMBaseRegisterInfo*>(TM.getRegisterInfo());
+    unsigned FramePtr = RegInfo->getFrameRegister(*(FuncInfo.MF));
+    unsigned SrcReg = FramePtr;
+
+    // Recursively load frame address
+    // ldr r0 [fp]
+    // ldr r0 [r0]
+    // ldr r0 [r0]
+    // ...
+    unsigned DestReg;
+    unsigned Depth = cast<ConstantInt>(I.getOperand(0))->getZExtValue();
+    while (Depth--) {
+      DestReg = createResultReg(RC);
+      AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
+                              TII.get(LdrOpc), DestReg)
+                      .addReg(SrcReg).addImm(0));
+      SrcReg = DestReg;
+    }
+    UpdateValueMap(&I, DestReg);
+    return true;
+  }
   case Intrinsic::memcpy:
   case Intrinsic::memmove: {
     const MemTransferInst &MTI = cast<MemTransferInst>(I);
diff --git a/test/CodeGen/ARM/fast-isel-frameaddr.ll b/test/CodeGen/ARM/fast-isel-frameaddr.ll
new file mode 100644
index 00000000000..8f7b2943b56
--- /dev/null
+++ b/test/CodeGen/ARM/fast-isel-frameaddr.ll
@@ -0,0 +1,100 @@
+; RUN: llc < %s -O0 -fast-isel-abort -mtriple=armv7-apple-darwin | FileCheck %s --check-prefix=DARWIN-ARM
+; RUN: llc < %s -O0 -fast-isel-abort -mtriple=armv7-linux-gnueabi | FileCheck %s --check-prefix=LINUX-ARM
+; RUN: llc < %s -O0 -fast-isel-abort -mtriple=thumbv7-apple-darwin | FileCheck %s --check-prefix=DARWIN-THUMB2
+; RUN: llc < %s -O0 -fast-isel-abort -mtriple=thumbv7-linux-gnueabi | FileCheck %s --check-prefix=LINUX-THUMB2
+
+define i8* @frameaddr_index0() nounwind {
+entry:
+; DARWIN-ARM: frameaddr_index0:
+; DARWIN-ARM: push {r7}
+; DARWIN-ARM: mov r7, sp
+; DARWIN-ARM: mov r0, r7
+
+; DARWIN-THUMB2: frameaddr_index0:
+; DARWIN-THUMB2: str r7, [sp, #-4]!
+; DARWIN-THUMB2: mov r7, sp
+; DARWIN-THUMB2: mov r0, r7
+
+; LINUX-ARM: frameaddr_index0:
+; LINUX-ARM: push {r11}
+; LINUX-ARM: mov r11, sp
+; LINUX-ARM: mov r0, r11
+
+; LINUX-THUMB2: frameaddr_index0:
+; LINUX-THUMB2: str r7, [sp, #-4]!
+; LINUX-THUMB2: mov r7, sp
+; LINUX-THUMB2: mov r0, r7
+
+  %0 = call i8* @llvm.frameaddress(i32 0)
+  ret i8* %0
+}
+
+define i8* @frameaddr_index1() nounwind {
+entry:
+; DARWIN-ARM: frameaddr_index1:
+; DARWIN-ARM: push {r7}
+; DARWIN-ARM: mov r7, sp
+; DARWIN-ARM: mov r0, r7
+; DARWIN-ARM: ldr r0, [r0]
+
+; DARWIN-THUMB2: frameaddr_index1:
+; DARWIN-THUMB2: str r7, [sp, #-4]!
+; DARWIN-THUMB2: mov r7, sp
+; DARWIN-THUMB2: mov r0, r7
+; DARWIN-THUMB2: ldr r0, [r0]
+
+; LINUX-ARM: frameaddr_index1:
+; LINUX-ARM: push {r11}
+; LINUX-ARM: mov r11, sp
+; LINUX-ARM: mov r0, r11
+; LINUX-ARM: ldr r0, [r0]
+
+; LINUX-THUMB2: frameaddr_index1:
+; LINUX-THUMB2: str r7, [sp, #-4]!
+; LINUX-THUMB2: mov r7, sp
+; LINUX-THUMB2: mov r0, r7
+; LINUX-THUMB2: ldr r0, [r0]
+
+  %0 = call i8* @llvm.frameaddress(i32 1)
+  ret i8* %0
+}
+
+define i8* @frameaddr_index3() nounwind {
+entry:
+; DARWIN-ARM: frameaddr_index3:
+; DARWIN-ARM: push {r7}
+; DARWIN-ARM: mov r7, sp
+; DARWIN-ARM: mov r0, r7
+; DARWIN-ARM: ldr r0, [r0]
+; DARWIN-ARM: ldr r0, [r0]
+; DARWIN-ARM: ldr r0, [r0]
+
+; DARWIN-THUMB2: frameaddr_index3:
+; DARWIN-THUMB2: str r7, [sp, #-4]!
+; DARWIN-THUMB2: mov r7, sp
+; DARWIN-THUMB2: mov r0, r7
+; DARWIN-THUMB2: ldr r0, [r0]
+; DARWIN-THUMB2: ldr r0, [r0]
+; DARWIN-THUMB2: ldr r0, [r0]
+
+; LINUX-ARM: frameaddr_index3:
+; LINUX-ARM: push {r11}
+; LINUX-ARM: mov r11, sp
+; LINUX-ARM: mov r0, r11
+; LINUX-ARM: ldr r0, [r0]
+; LINUX-ARM: ldr r0, [r0]
+; LINUX-ARM: ldr r0, [r0]
+
+; LINUX-THUMB2: frameaddr_index3:
+; LINUX-THUMB2: str r7, [sp, #-4]!
+; LINUX-THUMB2: mov r7, sp
+; LINUX-THUMB2: mov r0, r7
+; LINUX-THUMB2: ldr r0, [r0]
+; LINUX-THUMB2: ldr r0, [r0]
+; LINUX-THUMB2: ldr r0, [r0]
+
+  %0 = call i8* @llvm.frameaddress(i32 3)
+  ret i8* %0
+}
+
+declare i8* @llvm.frameaddress(i32) nounwind readnone