During local stack slot allocation, the materializeFrameBaseRegister function

may be called. If the entry block is empty, the insertion point iterator will be
the "end()" value. Calling ->getParent() on it (among others) causes problems.

Modify materializeFrameBaseRegister to take the machine basic block and insert
the frame base register at the beginning of that block. (It's very similar to
what the code does all ready. The only difference is that it will always insert
at the beginning of the entry block instead of after a previous materialization
of the frame base register. I doubt that that matters here.)

<rdar://problem/8782198>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122104 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/Target/TargetRegisterInfo.h b/include/llvm/Target/TargetRegisterInfo.h
index ceb61300ae156e8b6b229db264f827a2a300132c..05ccf04ec768661f991dfeab6eb2673db826eced 100644 (file)
--- a/include/llvm/Target/TargetRegisterInfo.h
+++ b/include/llvm/Target/TargetRegisterInfo.h
@@ -644,7 +644,7 @@ public:
 
   /// materializeFrameBaseRegister - Insert defining instruction(s) for
   /// BaseReg to be a pointer to FrameIdx before insertion point I.
-  virtual void materializeFrameBaseRegister(MachineBasicBlock::iterator I,
+  virtual void materializeFrameBaseRegister(MachineBasicBlock *MBB,
                                             unsigned BaseReg, int FrameIdx,
                                             int64_t Offset) const {
     assert(0 && "materializeFrameBaseRegister does not exist on this target");

diff --git a/lib/CodeGen/LocalStackSlotAllocation.cpp b/lib/CodeGen/LocalStackSlotAllocation.cpp
index 7e366f0ceec02e5f6225715aa51bea42b79220a8..38a69825534eb8ca7f8d01527c67a2ba02f6d68b 100644 (file)
--- a/lib/CodeGen/LocalStackSlotAllocation.cpp
+++ b/lib/CodeGen/LocalStackSlotAllocation.cpp
@@ -230,24 +230,25 @@ bool LocalStackSlotPass::insertFrameReferenceRegisters(MachineFunction &Fn) {
   const TargetFrameInfo &TFI = *Fn.getTarget().getFrameInfo();
   bool StackGrowsDown =
     TFI.getStackGrowthDirection() == TargetFrameInfo::StackGrowsDown;
-  MachineBasicBlock::iterator InsertionPt = Fn.begin()->begin();
 
   // Collect all of the instructions in the block that reference
   // a frame index. Also store the frame index referenced to ease later
   // lookup. (For any insn that has more than one FI reference, we arbitrarily
   // choose the first one).
   SmallVector<FrameRef, 64> FrameReferenceInsns;
-  // A base register definition is a register+offset pair.
-  SmallVector<std::pair<unsigned, int64_t>, 8> BaseRegisters;
 
+  // A base register definition is a register + offset pair.
+  SmallVector<std::pair<unsigned, int64_t>, 8> BaseRegisters;
 
   for (MachineFunction::iterator BB = Fn.begin(), E = Fn.end(); BB != E; ++BB) {
     for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ++I) {
       MachineInstr *MI = I;
+
       // Debug value instructions can't be out of range, so they don't need
       // any updates.
       if (MI->isDebugValue())
         continue;
+
       // For now, allocate the base register(s) within the basic block
       // where they're used, and don't try to keep them around outside
       // of that. It may be beneficial to try sharing them more broadly
@@ -268,11 +269,13 @@ bool LocalStackSlotPass::insertFrameReferenceRegisters(MachineFunction &Fn) {
       }
     }
   }
+
   // Sort the frame references by local offset
   array_pod_sort(FrameReferenceInsns.begin(), FrameReferenceInsns.end());
 
+  MachineBasicBlock *Entry = Fn.begin();
 
-  // Loop throught the frame references and allocate for them as necessary
+  // Loop through the frame references and allocate for them as necessary.
   for (int ref = 0, e = FrameReferenceInsns.size(); ref < e ; ++ref) {
     MachineBasicBlock::iterator I =
       FrameReferenceInsns[ref].getMachineInstr();
@@ -321,10 +324,12 @@ bool LocalStackSlotPass::insertFrameReferenceRegisters(MachineFunction &Fn) {
             DEBUG(dbgs() << "  Materializing base register " << BaseReg <<
                   " at frame local offset " <<
                   LocalOffsets[FrameIdx] + InstrOffset << "\n");
+
             // Tell the target to insert the instruction to initialize
             // the base register.
-            TRI->materializeFrameBaseRegister(InsertionPt, BaseReg,
-                                              FrameIdx, InstrOffset);
+            //            MachineBasicBlock::iterator InsertionPt = Entry->begin();
+            TRI->materializeFrameBaseRegister(Entry, BaseReg, FrameIdx,
+                                              InstrOffset);
 
             // The base register already includes any offset specified
             // by the instruction, so account for that so it doesn't get

diff --git a/lib/Target/ARM/ARMBaseRegisterInfo.cpp b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
index bdecaca37d0ece0002c2550e516a625b31d32cc7..9928105d21427f33666db315423fe60648111f52 100644 (file)
--- a/lib/Target/ARM/ARMBaseRegisterInfo.cpp
+++ b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
@@ -1029,19 +1029,25 @@ needsFrameBaseReg(MachineInstr *MI, int64_t Offset) const {
   return true;
 }
 
-/// materializeFrameBaseRegister - Insert defining instruction(s) for
-/// BaseReg to be a pointer to FrameIdx before insertion point I.
+/// materializeFrameBaseRegister - Insert defining instruction(s) for BaseReg to
+/// be a pointer to FrameIdx at the beginning of the basic block.
 void ARMBaseRegisterInfo::
-materializeFrameBaseRegister(MachineBasicBlock::iterator I, unsigned BaseReg,
-                             int FrameIdx, int64_t Offset) const {
-  ARMFunctionInfo *AFI =
-    I->getParent()->getParent()->getInfo<ARMFunctionInfo>();
+materializeFrameBaseRegister(MachineBasicBlock *MBB,
+                             unsigned BaseReg, int FrameIdx,
+                             int64_t Offset) const {
+  ARMFunctionInfo *AFI = MBB->getParent()->getInfo<ARMFunctionInfo>();
   unsigned ADDriOpc = !AFI->isThumbFunction() ? ARM::ADDri :
     (AFI->isThumb1OnlyFunction() ? ARM::tADDrSPi : ARM::t2ADDri);
 
+  MachineBasicBlock::iterator Ins = MBB->begin();
+  DebugLoc DL;                  // Defaults to "unknown"
+  if (Ins != MBB->end())
+    DL = Ins->getDebugLoc();
+
   MachineInstrBuilder MIB =
-    BuildMI(*I->getParent(), I, I->getDebugLoc(), TII.get(ADDriOpc), BaseReg)
+    BuildMI(*MBB, Ins, DL, TII.get(ADDriOpc), BaseReg)
     .addFrameIndex(FrameIdx).addImm(Offset);
+
   if (!AFI->isThumb1OnlyFunction())
     AddDefaultCC(AddDefaultPred(MIB));
 }

diff --git a/lib/Target/ARM/ARMBaseRegisterInfo.h b/lib/Target/ARM/ARMBaseRegisterInfo.h
index 23a466fad9549a4aa825d26b2cc9281cb3194286..ba6bd2b320822ff846739a2ff08a739fc8b27ad9 100644 (file)
--- a/lib/Target/ARM/ARMBaseRegisterInfo.h
+++ b/lib/Target/ARM/ARMBaseRegisterInfo.h
@@ -145,7 +145,7 @@ public:
   bool needsStackRealignment(const MachineFunction &MF) const;
   int64_t getFrameIndexInstrOffset(const MachineInstr *MI, int Idx) const;
   bool needsFrameBaseReg(MachineInstr *MI, int64_t Offset) const;
-  void materializeFrameBaseRegister(MachineBasicBlock::iterator I,
+  void materializeFrameBaseRegister(MachineBasicBlock *MBB,
                                     unsigned BaseReg, int FrameIdx,
                                     int64_t Offset) const;
   void resolveFrameIndex(MachineBasicBlock::iterator I,

diff --git a/test/CodeGen/ARM/2010-12-17-LocalStackSlotCrash.ll b/test/CodeGen/ARM/2010-12-17-LocalStackSlotCrash.ll
new file mode 100644 (file)
index 0000000..a2f50b5
--- /dev/null
+++ b/test/CodeGen/ARM/2010-12-17-LocalStackSlotCrash.ll
@@ -0,0 +1,15 @@
+; RUN: llc < %s -mtriple=armv6-apple-darwin10
+; <rdar://problem/8782198>
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:32:64-v128:32:128-a0:0:64-n32"
+target triple = "armv6-apple-darwin10"
+
+define void @func() nounwind optsize {
+entry:
+  %buf = alloca [8096 x i8], align 1
+  br label %bb
+
+bb:
+  %p.2 = getelementptr [8096 x i8]* %buf, i32 0, i32 0
+  store i8 undef, i8* %p.2, align 1
+  ret void
+}