MIR: Serialize a few bool function fields

[MatzeB]

Do you know whether we could compute their values instead? If the data can be derived by analyzing the function then we can add it to MIRParserImpl::computeFunctionProperties to compute them instead of explicitly serializing them.

[arsenm]

In D123863#3454299, @MatzeB wrote:

Do you know whether we could compute their values instead? If the data can be derived by analyzing the function then we can add it to MIRParserImpl::computeFunctionProperties to compute them instead of explicitly serializing them.

CallsUnwindInit tracks a call to an IR intrinsic which is immediately discarded, so no.

For HasEHScopes, HasEHFunclets, and HasOpaqueSPAdjustment, I don't think so. It's set directly from the IR (and I think it's better to avoid as many backlinks there as possible).

For HasEHCatchret, it would require some kind of target knowledge to know what they selected ISD::CATCHRET to.

[MatzeB]

At a first glance:

• HasEHFunclets and HasEHScopes both seem to be true iff there's an EHPad basic block which should be testable with MBB.isEHPad? Admittedly I don't understand why those two variables, it seems we only ever set them both in FunctionLoweringInfo::set...
• I guess CallsUnwind, CallsEHReturn, HasEHCatchret has no easy/obvious way to compute since patterns vary by target once things are lowered.

So yeah I think computing Funclets/Scopes is worth a try unless I am missing something.

Either way this change LGTM

[arsenm]

In D123863#3454366, @MatzeB wrote:

At a first glance:

• HasEHFunclets and HasEHScopes both seem to be true iff there's an EHPad basic block which should be testable with MBB.isEHPad? Admittedly I don't understand why those two variables, it seems we only ever set them both in FunctionLoweringInfo::set...

But it's set conditionally based on isa<LandingPadInst>(BB.getFirstNonPHI()), so EHPad doesn't necessarily imply them (but I have no understanding of how this exception stuff is supposed to work)

[MatzeB]

In D123863#3454376, @arsenm wrote:

In D123863#3454366, @MatzeB wrote:

At a first glance:

• HasEHFunclets and HasEHScopes both seem to be true iff there's an EHPad basic block which should be testable with MBB.isEHPad? Admittedly I don't understand why those two variables, it seems we only ever set them both in FunctionLoweringInfo::set...

But it's set conditionally based on isa<LandingPadInst>(BB.getFirstNonPHI()), so EHPad doesn't necessarily imply them (but I have no understanding of how this exception stuff is supposed to work)

I don't really have experience with EH either. So let's go ahead with the patch as-is then.

[rnk]

lgtm

It might be possible to recompute these, but I don't think it would be reliable.

[arsenm]

b8033de063f23252ac8c914965a7d7d5ef188352

llvm/include/llvm/CodeGen/MIRYamlMapping.h

struct MachineFunction {
   // GISel MachineFunctionProperties.
   bool Legalized = false;
   bool RegBankSelected = false;
   bool Selected = false;
   bool FailedISel = false;
   // Register information
   bool TracksRegLiveness = false;
   bool HasWinCFI = false;
+
+  bool CallsEHReturn = false;
+  bool CallsUnwindInit = false;
+  bool HasEHCatchret = false;
+  bool HasEHScopes = false;
+  bool HasEHFunclets = false;
+
   bool FailsVerification = false;
   bool TracksDebugUserValues = false;
   std::vector<VirtualRegisterDefinition> VirtualRegisters;
   std::vector<MachineFunctionLiveIn> LiveIns;
   Optional<std::vector<FlowStringValue>> CalleeSavedRegisters;
   // TODO: Serialize the various register masks.
   // Frame information
   MachineFrameInfo FrameInfo;
static void mapping(IO &YamlIO, MachineFunction &MF) {
     YamlIO.mapOptional("alignment", MF.Alignment, None);
     YamlIO.mapOptional("exposesReturnsTwice", MF.ExposesReturnsTwice, false);
     YamlIO.mapOptional("legalized", MF.Legalized, false);
     YamlIO.mapOptional("regBankSelected", MF.RegBankSelected, false);
     YamlIO.mapOptional("selected", MF.Selected, false);
     YamlIO.mapOptional("failedISel", MF.FailedISel, false);
     YamlIO.mapOptional("tracksRegLiveness", MF.TracksRegLiveness, false);
     YamlIO.mapOptional("hasWinCFI", MF.HasWinCFI, false);
+
+    YamlIO.mapOptional("callsEHReturn", MF.CallsEHReturn, false);
+    YamlIO.mapOptional("callsUnwindInit", MF.CallsUnwindInit, false);
+    YamlIO.mapOptional("hasEHCatchret", MF.HasEHCatchret, false);
+    YamlIO.mapOptional("hasEHScopes", MF.HasEHScopes, false);
+    YamlIO.mapOptional("hasEHFunclets", MF.HasEHFunclets, false);
+
     YamlIO.mapOptional("failsVerification", MF.FailsVerification, false);
     YamlIO.mapOptional("tracksDebugUserValues", MF.TracksDebugUserValues,
                        false);
     YamlIO.mapOptional("registers", MF.VirtualRegisters,
                        std::vector<VirtualRegisterDefinition>());
     YamlIO.mapOptional("liveins", MF.LiveIns,
                        std::vector<MachineFunctionLiveIn>());
     YamlIO.mapOptional("calleeSavedRegisters", MF.CalleeSavedRegisters,

llvm/lib/CodeGen/MIRParser/MIRParser.cpp

MIRParserImpl::initializeMachineFunction(const yaml::MachineFunction &YamlMF,
   } else {
     Target.reset(new PerTargetMIParsingState(MF.getSubtarget()));
   }
 
   MF.setAlignment(YamlMF.Alignment.valueOrOne());
   MF.setExposesReturnsTwice(YamlMF.ExposesReturnsTwice);
   MF.setHasWinCFI(YamlMF.HasWinCFI);
 
+  MF.setCallsEHReturn(YamlMF.CallsEHReturn);
+  MF.setCallsUnwindInit(YamlMF.CallsUnwindInit);
+  MF.setHasEHCatchret(YamlMF.HasEHCatchret);
+  MF.setHasEHScopes(YamlMF.HasEHScopes);
+  MF.setHasEHFunclets(YamlMF.HasEHFunclets);
+
   if (YamlMF.Legalized)
     MF.getProperties().set(MachineFunctionProperties::Property::Legalized);
   if (YamlMF.RegBankSelected)
     MF.getProperties().set(
         MachineFunctionProperties::Property::RegBankSelected);
   if (YamlMF.Selected)
     MF.getProperties().set(MachineFunctionProperties::Property::Selected);
   if (YamlMF.FailedISel)

llvm/lib/CodeGen/MIRPrinter.cpp

void MIRPrinter::print(const MachineFunction &MF) {
   initRegisterMaskIds(MF);
 
   yaml::MachineFunction YamlMF;
   YamlMF.Name = MF.getName();
   YamlMF.Alignment = MF.getAlignment();
   YamlMF.ExposesReturnsTwice = MF.exposesReturnsTwice();
   YamlMF.HasWinCFI = MF.hasWinCFI();
 
+  YamlMF.CallsEHReturn = MF.callsEHReturn();
+  YamlMF.CallsUnwindInit = MF.callsUnwindInit();
+  YamlMF.HasEHCatchret = MF.hasEHCatchret();
+  YamlMF.HasEHScopes = MF.hasEHScopes();
+  YamlMF.HasEHFunclets = MF.hasEHFunclets();
+
   YamlMF.Legalized = MF.getProperties().hasProperty(
       MachineFunctionProperties::Property::Legalized);
   YamlMF.RegBankSelected = MF.getProperties().hasProperty(
       MachineFunctionProperties::Property::RegBankSelected);
   YamlMF.Selected = MF.getProperties().hasProperty(
       MachineFunctionProperties::Property::Selected);
   YamlMF.FailedISel = MF.getProperties().hasProperty(
       MachineFunctionProperties::Property::FailedISel);

llvm/test/CodeGen/MIR/X86/exception-function-state.mir

+# RUN: llc -simplify-mir=0 -march=x86-64 -run-pass=none -o - %s | FileCheck -check-prefixes=FULL,ALL %s
+# RUN: llc -simplify-mir=1 -march=x86-64 -run-pass=none -o - %s | FileCheck -check-prefixes=SIMPLE,ALL %s
+
+# This test ensures that the MIR parser parses callee saved information in the
+# stack objects correctly.
+
+# ALL: name: func0
+# ALL: callsEHReturn:   true
+# ALL: callsUnwindInit: true
+# ALL: hasEHCatchret:   true
+# ALL: hasEHScopes:     true
+# ALL: hasEHFunclets:   true
+
+---
+name: func0
+callsEHReturn: true
+callsUnwindInit: true
+hasEHCatchret: true
+hasEHScopes: true
+hasEHFunclets: true
+body: |
+  bb.0:
+...
+
+# ALL: name: func1
+# FULL: callsEHReturn: false
+# FULL: callsUnwindInit: true
+# FULL: hasEHCatchret: false
+# FULL: hasEHScopes: true
+# FULL: hasEHFunclets: false
+
+# SIMPLE-NOT: callsEHReturn
+# SIMPLE: callsUnwindInit: true
+# SIMPLE-NOT: hasEHCatchret
+# SIMPLE: hasEHScopes: true
+# SIMPLE-NOT: hasEHFunclets
+---
+name: func1
+tracksRegLiveness: true
+callsEHReturn: false
+callsUnwindInit: true
+hasEHCatchret: false
+hasEHScopes: true
+hasEHFunclets: false
+body: |
+  bb.0:
+...
+
+# ALL: name: func2
+# FULL: callsEHReturn: true
+# FULL: callsUnwindInit: false
+# FULL: hasEHCatchret: true
+# FULL: hasEHScopes: false
+# FULL: hasEHFunclets: false
+
+# SIMPLE: callsEHReturn: true
+# SIMPLE-NOT: callsUnwindInit
+# SIMPLE: hasEHCatchret: true
+# SIMPLE-NOT hasEHScopes
+# SIMPLE-NOT: hasEHFunclets
+---
+name: func2
+tracksRegLiveness: true
+callsEHReturn: true
+callsUnwindInit: false
+hasEHCatchret: true
+hasEHScopes: false
+hasEHFunclets: false
+body: |
+  bb.0:
+...