From 8b61764cbba4136e038fd94e035f1e965c82ba52 Mon Sep 17 00:00:00 2001
From: Francis Visoiu Mistrih <fvisoiumistrih@apple.com>
Date: Thu, 18 May 2017 17:21:13 +0000
Subject: [LegacyPassManager] Remove TargetMachine constructors

This provides a new way to access the TargetMachine through
TargetPassConfig, as a dependency.

The patterns replaced here are:

* Passes handling a null TargetMachine call
  `getAnalysisIfAvailable<TargetPassConfig>`.

* Passes not handling a null TargetMachine
  `addRequired<TargetPassConfig>` and call
  `getAnalysis<TargetPassConfig>`.

* MachineFunctionPasses now use MF.getTarget().

* Remove all the TargetMachine constructors.
* Remove INITIALIZE_TM_PASS.

This fixes a crash when running `llc -start-before prologepilog`.

PEI needs StackProtector, which gets constructed without a TargetMachine
by the pass manager. The StackProtector pass doesn't handle the case
where there is no TargetMachine, so it segfaults.

Related to PR30324.

Differential Revision: https://reviews.llvm.org/D33222

llvm-svn: 303360
---
 llvm/lib/CodeGen/PrologEpilogInserter.cpp | 42 ++++++++++++++++---------------
 1 file changed, 22 insertions(+), 20 deletions(-)

(limited to 'llvm/lib/CodeGen/PrologEpilogInserter.cpp')

diff --git a/llvm/lib/CodeGen/PrologEpilogInserter.cpp b/llvm/lib/CodeGen/PrologEpilogInserter.cpp
index d2afeae9e70..aaa253fde49 100644
--- a/llvm/lib/CodeGen/PrologEpilogInserter.cpp
+++ b/llvm/lib/CodeGen/PrologEpilogInserter.cpp
@@ -60,19 +60,8 @@ namespace {
 class PEI : public MachineFunctionPass {
 public:
   static char ID;
-  explicit PEI(const TargetMachine *TM = nullptr) : MachineFunctionPass(ID) {
+  PEI() : MachineFunctionPass(ID) {
     initializePEIPass(*PassRegistry::getPassRegistry());
-
-    if (TM && (!TM->usesPhysRegsForPEI())) {
-      SpillCalleeSavedRegisters = [](MachineFunction &, RegScavenger *,
-                                     unsigned &, unsigned &, const MBBVector &,
-                                     const MBBVector &) {};
-      ScavengeFrameVirtualRegs = [](MachineFunction &, RegScavenger *) {};
-    } else {
-      SpillCalleeSavedRegisters = doSpillCalleeSavedRegs;
-      ScavengeFrameVirtualRegs = doScavengeFrameVirtualRegs;
-      UsesCalleeSaves = true;
-    }
   }
 
   void getAnalysisUsage(AnalysisUsage &AU) const override;
@@ -140,18 +129,17 @@ WarnStackSize("warn-stack-size", cl::Hidden, cl::init((unsigned)-1),
               cl::desc("Warn for stack size bigger than the given"
                        " number"));
 
-INITIALIZE_TM_PASS_BEGIN(PEI, "prologepilog", "Prologue/Epilogue Insertion",
-                         false, false)
+INITIALIZE_PASS_BEGIN(PEI, "prologepilog", "Prologue/Epilogue Insertion", false,
+                      false)
 INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo)
 INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
 INITIALIZE_PASS_DEPENDENCY(StackProtector)
-INITIALIZE_TM_PASS_END(PEI, "prologepilog",
-                       "Prologue/Epilogue Insertion & Frame Finalization",
-                       false, false)
+INITIALIZE_PASS_END(PEI, "prologepilog",
+                    "Prologue/Epilogue Insertion & Frame Finalization", false,
+                    false)
 
-MachineFunctionPass *
-llvm::createPrologEpilogInserterPass(const TargetMachine *TM) {
-  return new PEI(TM);
+MachineFunctionPass *llvm::createPrologEpilogInserterPass() {
+  return new PEI();
 }
 
 STATISTIC(NumScavengedRegs, "Number of frame index regs scavenged");
@@ -174,6 +162,20 @@ typedef SmallSetVector<int, 8> StackObjSet;
 /// frame indexes with appropriate references.
 ///
 bool PEI::runOnMachineFunction(MachineFunction &Fn) {
+  if (!SpillCalleeSavedRegisters) {
+    const TargetMachine &TM = Fn.getTarget();
+    if (!TM.usesPhysRegsForPEI()) {
+      SpillCalleeSavedRegisters = [](MachineFunction &, RegScavenger *,
+                                     unsigned &, unsigned &, const MBBVector &,
+                                     const MBBVector &) {};
+      ScavengeFrameVirtualRegs = [](MachineFunction &, RegScavenger *) {};
+    } else {
+      SpillCalleeSavedRegisters = doSpillCalleeSavedRegs;
+      ScavengeFrameVirtualRegs = doScavengeFrameVirtualRegs;
+      UsesCalleeSaves = true;
+    }
+  }
+
   const Function* F = Fn.getFunction();
   const TargetRegisterInfo *TRI = Fn.getSubtarget().getRegisterInfo();
   const TargetFrameLowering *TFI = Fn.getSubtarget().getFrameLowering();
-- 
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