1 files changed, 62 insertions, 19 deletions

diff --git a/lib/Target/PowerPC/PPCBranchSelector.cpp b/lib/Target/PowerPC/PPCBranchSelector.cpp
index 4d63c5b5703c..ae76386fdfb6 100644
--- a/lib/Target/PowerPC/PPCBranchSelector.cpp
+++ b/lib/Target/PowerPC/PPCBranchSelector.cpp
@@ -19,8 +19,10 @@
 #include "MCTargetDesc/PPCPredicates.h"
 #include "PPCInstrBuilder.h"
 #include "PPCInstrInfo.h"
+#include "PPCSubtarget.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetSubtargetInfo.h"
@@ -41,19 +43,19 @@ namespace {
       initializePPCBSelPass(*PassRegistry::getPassRegistry());
     }
 
-    /// BlockSizes - The sizes of the basic blocks in the function.
-    std::vector<unsigned> BlockSizes;
+    // The sizes of the basic blocks in the function (the first
+    // element of the pair); the second element of the pair is the amount of the
+    // size that is due to potential padding.
+    std::vector<std::pair<unsigned, unsigned>> BlockSizes;
 
     bool runOnMachineFunction(MachineFunction &Fn) override;
 
     MachineFunctionProperties getRequiredProperties() const override {
       return MachineFunctionProperties().set(
-          MachineFunctionProperties::Property::AllVRegsAllocated);
+          MachineFunctionProperties::Property::NoVRegs);
     }
 
-    const char *getPassName() const override {
-      return "PowerPC Branch Selector";
-    }
+    StringRef getPassName() const override { return "PowerPC Branch Selector"; }
   };
   char PPCBSel::ID = 0;
 }
@@ -92,8 +94,19 @@ bool PPCBSel::runOnMachineFunction(MachineFunction &Fn) {
     return AlignAmt + OffsetToAlignment(Offset, AlignAmt);
   };
 
+  // We need to be careful about the offset of the first block in the function
+  // because it might not have the function's alignment. This happens because,
+  // under the ELFv2 ABI, for functions which require a TOC pointer, we add a
+  // two-instruction sequence to the start of the function.
+  // Note: This needs to be synchronized with the check in
+  // PPCLinuxAsmPrinter::EmitFunctionBodyStart.
+  unsigned InitialOffset = 0;
+  if (Fn.getSubtarget<PPCSubtarget>().isELFv2ABI() &&
+      !Fn.getRegInfo().use_empty(PPC::X2))
+    InitialOffset = 8;
+
   // Measure each MBB and compute a size for the entire function.
-  unsigned FuncSize = 0;
+  unsigned FuncSize = InitialOffset;
   for (MachineFunction::iterator MFI = Fn.begin(), E = Fn.end(); MFI != E;
        ++MFI) {
     MachineBasicBlock *MBB = &*MFI;
@@ -102,15 +115,19 @@ bool PPCBSel::runOnMachineFunction(MachineFunction &Fn) {
     // alignment requirement.
     if (MBB->getNumber() > 0) {
       unsigned AlignExtra = GetAlignmentAdjustment(*MBB, FuncSize);
-      BlockSizes[MBB->getNumber()-1] += AlignExtra;
+
+      auto &BS = BlockSizes[MBB->getNumber()-1];
+      BS.first += AlignExtra;
+      BS.second = AlignExtra;
+
       FuncSize += AlignExtra;
     }
 
     unsigned BlockSize = 0;
     for (MachineInstr &MI : *MBB)
-      BlockSize += TII->GetInstSizeInBytes(MI);
+      BlockSize += TII->getInstSizeInBytes(MI);
 
-    BlockSizes[MBB->getNumber()] = BlockSize;
+    BlockSizes[MBB->getNumber()].first = BlockSize;
     FuncSize += BlockSize;
   }
   
@@ -155,7 +172,7 @@ bool PPCBSel::runOnMachineFunction(MachineFunction &Fn) {
           Dest = I->getOperand(0).getMBB();
 
         if (!Dest) {
-          MBBStartOffset += TII->GetInstSizeInBytes(*I);
+          MBBStartOffset += TII->getInstSizeInBytes(*I);
           continue;
         }
         
@@ -169,14 +186,14 @@ bool PPCBSel::runOnMachineFunction(MachineFunction &Fn) {
           BranchSize = MBBStartOffset;
           
           for (unsigned i = Dest->getNumber(), e = MBB.getNumber(); i != e; ++i)
-            BranchSize += BlockSizes[i];
+            BranchSize += BlockSizes[i].first;
         } else {
           // Otherwise, add the size of the blocks between this block and the
           // dest to the number of bytes left in this block.
           BranchSize = -MBBStartOffset;
 
           for (unsigned i = MBB.getNumber(), e = Dest->getNumber(); i != e; ++i)
-            BranchSize += BlockSizes[i];
+            BranchSize += BlockSizes[i].first;
         }
 
         // If this branch is in range, ignore it.
@@ -186,9 +203,9 @@ bool PPCBSel::runOnMachineFunction(MachineFunction &Fn) {
         }
 
         // Otherwise, we have to expand it to a long branch.
-        MachineInstr *OldBranch = I;
-        DebugLoc dl = OldBranch->getDebugLoc();
- 
+        MachineInstr &OldBranch = *I;
+        DebugLoc dl = OldBranch.getDebugLoc();
+
         if (I->getOpcode() == PPC::BCC) {
           // The BCC operands are:
           // 0. PPC branch predicate
@@ -222,16 +239,42 @@ bool PPCBSel::runOnMachineFunction(MachineFunction &Fn) {
         I = BuildMI(MBB, I, dl, TII->get(PPC::B)).addMBB(Dest);
 
         // Remove the old branch from the function.
-        OldBranch->eraseFromParent();
-        
+        OldBranch.eraseFromParent();
+
         // Remember that this instruction is 8-bytes, increase the size of the
         // block by 4, remember to iterate.
-        BlockSizes[MBB.getNumber()] += 4;
+        BlockSizes[MBB.getNumber()].first += 4;
         MBBStartOffset += 8;
         ++NumExpanded;
         MadeChange = true;
       }
     }
+
+    if (MadeChange) {
+      // If we're going to iterate again, make sure we've updated our
+      // padding-based contributions to the block sizes.
+      unsigned Offset = InitialOffset;
+      for (MachineFunction::iterator MFI = Fn.begin(), E = Fn.end(); MFI != E;
+           ++MFI) {
+        MachineBasicBlock *MBB = &*MFI;
+
+        if (MBB->getNumber() > 0) {
+          auto &BS = BlockSizes[MBB->getNumber()-1];
+          BS.first -= BS.second;
+          Offset -= BS.second;
+
+          unsigned AlignExtra = GetAlignmentAdjustment(*MBB, Offset);
+
+          BS.first += AlignExtra;
+          BS.second = AlignExtra;
+
+          Offset += AlignExtra;
+        }
+
+        Offset += BlockSizes[MBB->getNumber()].first;
+      }
+    }
+
     EverMadeChange |= MadeChange;
   }