From 1f9c3ec831cf63f7833680c38362c1e92c251aff Mon Sep 17 00:00:00 2001
From: Jakob Stoklund Olesen <stoklund@2pi.dk>
Date: Wed, 6 Jun 2012 22:34:30 +0000
Subject: [PATCH] Properly verify liveness with bundled machine instructions.

Bundles should be treated as one atomic transaction when checking
liveness. That is how the register allocator (and VLIW targets) treats
bundles.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158116 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/MachineVerifier.cpp | 47 ++++++++++++++++++++++++---------
 1 file changed, 34 insertions(+), 13 deletions(-)

diff --git a/lib/CodeGen/MachineVerifier.cpp b/lib/CodeGen/MachineVerifier.cpp
index 37d56f9d5dc..a5ee1d59f31 100644
--- a/lib/CodeGen/MachineVerifier.cpp
+++ b/lib/CodeGen/MachineVerifier.cpp
@@ -191,9 +191,11 @@ namespace {
 
     void visitMachineFunctionBefore();
     void visitMachineBasicBlockBefore(const MachineBasicBlock *MBB);
+    void visitMachineBundleBefore(const MachineInstr *MI);
     void visitMachineInstrBefore(const MachineInstr *MI);
     void visitMachineOperand(const MachineOperand *MO, unsigned MONum);
     void visitMachineInstrAfter(const MachineInstr *MI);
+    void visitMachineBundleAfter(const MachineInstr *MI);
     void visitMachineBasicBlockAfter(const MachineBasicBlock *MBB);
     void visitMachineFunctionAfter();
 
@@ -288,6 +290,8 @@ bool MachineVerifier::runOnMachineFunction(MachineFunction &MF) {
   for (MachineFunction::const_iterator MFI = MF.begin(), MFE = MF.end();
        MFI!=MFE; ++MFI) {
     visitMachineBasicBlockBefore(MFI);
+    // Keep track of the current bundle header.
+    const MachineInstr *CurBundle = 0;
     for (MachineBasicBlock::const_instr_iterator MBBI = MFI->instr_begin(),
            MBBE = MFI->instr_end(); MBBI != MBBE; ++MBBI) {
       if (MBBI->getParent() != MFI) {
@@ -295,15 +299,21 @@ bool MachineVerifier::runOnMachineFunction(MachineFunction &MF) {
         *OS << "Instruction: " << *MBBI;
         continue;
       }
-      // Skip BUNDLE instruction for now. FIXME: We should add code to verify
-      // the BUNDLE's specifically.
-      if (MBBI->isBundle())
-        continue;
+      // Is this a bundle header?
+      if (!MBBI->isInsideBundle()) {
+        if (CurBundle)
+          visitMachineBundleAfter(CurBundle);
+        CurBundle = MBBI;
+        visitMachineBundleBefore(CurBundle);
+      } else if (!CurBundle)
+        report("No bundle header", MBBI);
       visitMachineInstrBefore(MBBI);
       for (unsigned I = 0, E = MBBI->getNumOperands(); I != E; ++I)
         visitMachineOperand(&MBBI->getOperand(I), I);
       visitMachineInstrAfter(MBBI);
     }
+    if (CurBundle)
+      visitMachineBundleAfter(CurBundle);
     visitMachineBasicBlockAfter(MFI);
   }
   visitMachineFunctionAfter();
@@ -575,6 +585,19 @@ MachineVerifier::visitMachineBasicBlockBefore(const MachineBasicBlock *MBB) {
     lastIndex = Indexes->getMBBStartIdx(MBB);
 }
 
+// This function gets called for all bundle headers, including normal
+// stand-alone unbundled instructions.
+void MachineVerifier::visitMachineBundleBefore(const MachineInstr *MI) {
+  if (Indexes && Indexes->hasIndex(MI)) {
+    SlotIndex idx = Indexes->getInstructionIndex(MI);
+    if (!(idx > lastIndex)) {
+      report("Instruction index out of order", MI);
+      *OS << "Last instruction was at " << lastIndex << '\n';
+    }
+    lastIndex = idx;
+  }
+}
+
 void MachineVerifier::visitMachineInstrBefore(const MachineInstr *MI) {
   const MCInstrDesc &MCID = MI->getDesc();
   if (MI->getNumOperands() < MCID.getNumOperands()) {
@@ -865,6 +888,13 @@ void MachineVerifier::checkLiveness(const MachineOperand *MO, unsigned MONum) {
 }
 
 void MachineVerifier::visitMachineInstrAfter(const MachineInstr *MI) {
+}
+
+// This function gets called after visiting all instructions in a bundle. The
+// argument points to the bundle header.
+// Normal stand-alone instructions are also considered 'bundles', and this
+// function is called for all of them.
+void MachineVerifier::visitMachineBundleAfter(const MachineInstr *MI) {
   BBInfo &MInfo = MBBInfoMap[MI->getParent()];
   set_union(MInfo.regsKilled, regsKilled);
   set_subtract(regsLive, regsKilled); regsKilled.clear();
@@ -878,15 +908,6 @@ void MachineVerifier::visitMachineInstrAfter(const MachineInstr *MI) {
   }
   set_subtract(regsLive, regsDead);   regsDead.clear();
   set_union(regsLive, regsDefined);   regsDefined.clear();
-
-  if (Indexes && Indexes->hasIndex(MI)) {
-    SlotIndex idx = Indexes->getInstructionIndex(MI);
-    if (!(idx > lastIndex)) {
-      report("Instruction index out of order", MI);
-      *OS << "Last instruction was at " << lastIndex << '\n';
-    }
-    lastIndex = idx;
-  }
 }
 
 void