From 5590a4355f6d1196ebbbfe2c02f83efc70780443 Mon Sep 17 00:00:00 2001
From: Wolfgang Pieb <Wolfgang.Pieb@sony.com>
Date: Wed, 30 Jan 2019 18:34:07 +0000
Subject: [DEBUGINFO] Handle restore instructions in LiveDebugValues

The LiveDebugValues pass recognizes spills but not restores, which can
cause large gaps in location information for some variables, depending
on control flow. This patch make LiveDebugValues recognize restores and
generate appropriate DBG_VALUE instructions.

Reviewers: aprantl, NicolaPrica

Differential Revision: https://reviews.llvm.org/D57271

llvm-svn: 352642
---
 llvm/lib/CodeGen/MachineInstr.cpp | 54 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 53 insertions(+), 1 deletion(-)

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

diff --git a/llvm/lib/CodeGen/MachineInstr.cpp b/llvm/lib/CodeGen/MachineInstr.cpp
index 7ab17fce04d..fa3f7874b12 100644
--- a/llvm/lib/CodeGen/MachineInstr.cpp
+++ b/llvm/lib/CodeGen/MachineInstr.cpp
@@ -25,6 +25,7 @@
 #include "llvm/Analysis/MemoryLocation.h"
 #include "llvm/CodeGen/GlobalISel/RegisterBank.h"
 #include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineInstrBundle.h"
@@ -49,9 +50,9 @@
 #include "llvm/IR/Metadata.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/ModuleSlotTracker.h"
+#include "llvm/IR/Operator.h"
 #include "llvm/IR/Type.h"
 #include "llvm/IR/Value.h"
-#include "llvm/IR/Operator.h"
 #include "llvm/MC/MCInstrDesc.h"
 #include "llvm/MC/MCRegisterInfo.h"
 #include "llvm/MC/MCSymbol.h"
@@ -2100,3 +2101,54 @@ void MachineInstr::changeDebugValuesDefReg(unsigned Reg) {
   for (auto *DBI : DbgValues)
     DBI->getOperand(0).setReg(Reg);
 }
+
+using MMOList = SmallVector<const MachineMemOperand *, 2>;
+
+static unsigned getSpillSlotSize(MMOList &Accesses,
+                                 const MachineFrameInfo &MFI) {
+  unsigned Size = 0;
+  for (auto A : Accesses)
+    if (MFI.isSpillSlotObjectIndex(
+            cast<FixedStackPseudoSourceValue>(A->getPseudoValue())
+                ->getFrameIndex()))
+      Size += A->getSize();
+  return Size;
+}
+
+Optional<unsigned>
+MachineInstr::getSpillSize(const TargetInstrInfo *TII) const {
+  int FI;
+  if (TII->isStoreToStackSlotPostFE(*this, FI)) {
+    const MachineFrameInfo &MFI = getMF()->getFrameInfo();
+    if (MFI.isSpillSlotObjectIndex(FI))
+      return (*memoperands_begin())->getSize();
+  }
+  return None;
+}
+
+Optional<unsigned>
+MachineInstr::getFoldedSpillSize(const TargetInstrInfo *TII) const {
+  MMOList Accesses;
+  if (TII->hasStoreToStackSlot(*this, Accesses))
+    return getSpillSlotSize(Accesses, getMF()->getFrameInfo());
+  return None;
+}
+
+Optional<unsigned>
+MachineInstr::getRestoreSize(const TargetInstrInfo *TII) const {
+  int FI;
+  if (TII->isLoadFromStackSlotPostFE(*this, FI)) {
+    const MachineFrameInfo &MFI = getMF()->getFrameInfo();
+    if (MFI.isSpillSlotObjectIndex(FI))
+      return (*memoperands_begin())->getSize();
+  }
+  return None;
+}
+
+Optional<unsigned>
+MachineInstr::getFoldedRestoreSize(const TargetInstrInfo *TII) const {
+  MMOList Accesses;
+  if (TII->hasLoadFromStackSlot(*this, Accesses))
+    return getSpillSlotSize(Accesses, getMF()->getFrameInfo());
+  return None;
+}
-- 
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