From 1c8fccbc12e6348c8003aff9b89078324257fc4e Mon Sep 17 00:00:00 2001
From: Chad Rosier <mcrosier@apple.com>
Date: Wed, 23 May 2012 18:38:57 +0000
Subject: [PATCH] [arm-fast-isel] Add support for non-global callee. Patch by
 Jush Lu <jush.msn@gmail.com>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157336 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/ARMFastISel.cpp     | 24 +++++++++++++++++-------
 test/CodeGen/ARM/fast-isel-call.ll | 20 ++++++++++++++++++++
 2 files changed, 37 insertions(+), 7 deletions(-)

diff --git a/lib/Target/ARM/ARMFastISel.cpp b/lib/Target/ARM/ARMFastISel.cpp
index 97131cd6987..c13f283a847 100644
--- a/lib/Target/ARM/ARMFastISel.cpp
+++ b/lib/Target/ARM/ARMFastISel.cpp
@@ -2216,11 +2216,6 @@ bool ARMFastISel::SelectCall(const Instruction *I,
   // Can't handle inline asm.
   if (isa<InlineAsm>(Callee)) return false;
 
-  // Only handle global variable Callees.
-  const GlobalValue *GV = dyn_cast<GlobalValue>(Callee);
-  if (!GV)
-    return false;
-
   // Check the calling convention.
   ImmutableCallSite CS(CI);
   CallingConv::ID CC = CS.getCallingConv();
@@ -2313,18 +2308,33 @@ bool ARMFastISel::SelectCall(const Instruction *I,
 
   // Issue the call.
   MachineInstrBuilder MIB;
+  const GlobalValue *GV = dyn_cast<GlobalValue>(Callee);
   unsigned CallOpc = ARMSelectCallOp(GV);
+  unsigned CalleeReg = 0;
+
+  if (!GV){
+    CallOpc = isThumb2 ? ARM::tBLXr : ARM::BLX;
+    CalleeReg = getRegForValue(Callee);
+    if (CalleeReg == 0) return false;
+  }
+
   // Explicitly adding the predicate here.
   if(isThumb2) {
     // Explicitly adding the predicate here.
     MIB = AddDefaultPred(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
                                  TII.get(CallOpc)));
-    if (!IntrMemName)
+    if (!GV)
+      MIB.addReg(CalleeReg);
+    else if (!IntrMemName)
       MIB.addGlobalAddress(GV, 0, 0);
     else 
       MIB.addExternalSymbol(IntrMemName, 0);
   } else {
-    if (!IntrMemName)
+    if (!GV)
+      MIB = AddDefaultPred(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
+                                   TII.get(CallOpc))
+            .addReg(CalleeReg));
+    else if (!IntrMemName)
       // Explicitly adding the predicate here.
       MIB = AddDefaultPred(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
                                    TII.get(CallOpc))
diff --git a/test/CodeGen/ARM/fast-isel-call.ll b/test/CodeGen/ARM/fast-isel-call.ll
index dd460b2a036..10d6746acfd 100644
--- a/test/CodeGen/ARM/fast-isel-call.ll
+++ b/test/CodeGen/ARM/fast-isel-call.ll
@@ -126,3 +126,23 @@ entry:
 }
 
 declare i32 @bar(i8 zeroext, i8 zeroext, i8 zeroext, i8 zeroext, i8 zeroext, i8 zeroext)
+
+define i32 @bar0(i32 %i) nounwind {
+  ret i32 0
+}
+
+define void @foo3() uwtable {
+; ARM: movw    r0, #0
+; ARM: movw    r1, :lower16:_bar0
+; ARM: movt    r1, :upper16:_bar0
+; ARM: blx     r1
+; THUMB: movs    r0, #0
+; THUMB: movw    r1, :lower16:_bar0
+; THUMB: movt    r1, :upper16:_bar0
+; THUMB: blx     r1
+  %fptr = alloca i32 (i32)*, align 8
+  store i32 (i32)* @bar0, i32 (i32)** %fptr, align 8
+  %1 = load i32 (i32)** %fptr, align 8
+  %call = call i32 %1(i32 0)
+  ret void
+}