MIR Serialization: Serialize the fixed stack objects.

This commit serializes the fixed stack objects, including fixed spill slots.
The fixed stack objects are serialized using a YAML sequence of YAML inline
mappings. Each mapping has the object's ID, type, size, offset, and alignment.
The objects that aren't spill slots also serialize the isImmutable and isAliased
flags.

The fixed stack objects are a part of the machine function's YAML mapping.

Reviewers: Duncan P. N. Exon Smith
llvm-svn: 242045

llvm/include/llvm/CodeGen/MIRYamlMapping.h

@@ -129,7 +129,7 @@ template <> struct MappingTraits<MachineBasicBlock> {
 ///
 /// TODO: Determine isPreallocated flag by mapping between objects and local
 /// objects (Serialize local objects).
-/// TODO: Serialize variable sized and fixed stack objects.
+/// TODO: Serialize variable sized objects.
 struct MachineStackObject {
   enum ObjectType { DefaultType, SpillSlot };
   // TODO: Serialize LLVM alloca reference.
@@ -161,12 +161,53 @@ template <> struct MappingTraits<MachineStackObject> {
   static const bool flow = true;
 };
 
+/// Serializable representation of the fixed stack object from the
+/// MachineFrameInfo class.
+struct FixedMachineStackObject {
+  enum ObjectType { DefaultType, SpillSlot };
+  unsigned ID;
+  ObjectType Type = DefaultType;
+  int64_t Offset = 0;
+  uint64_t Size = 0;
+  unsigned Alignment = 0;
+  bool IsImmutable = false;
+  bool IsAliased = false;
+};
+
+template <>
+struct ScalarEnumerationTraits<FixedMachineStackObject::ObjectType> {
+  static void enumeration(yaml::IO &IO,
+                          FixedMachineStackObject::ObjectType &Type) {
+    IO.enumCase(Type, "default", FixedMachineStackObject::DefaultType);
+    IO.enumCase(Type, "spill-slot", FixedMachineStackObject::SpillSlot);
+  }
+};
+
+template <> struct MappingTraits<FixedMachineStackObject> {
+  static void mapping(yaml::IO &YamlIO, FixedMachineStackObject &Object) {
+    YamlIO.mapRequired("id", Object.ID);
+    YamlIO.mapOptional(
+        "type", Object.Type,
+        FixedMachineStackObject::DefaultType); // Don't print the default type.
+    YamlIO.mapOptional("offset", Object.Offset);
+    YamlIO.mapOptional("size", Object.Size);
+    YamlIO.mapOptional("alignment", Object.Alignment);
+    if (Object.Type != FixedMachineStackObject::SpillSlot) {
+      YamlIO.mapOptional("isImmutable", Object.IsImmutable);
+      YamlIO.mapOptional("isAliased", Object.IsAliased);
+    }
+  }
+
+  static const bool flow = true;
+};
+
 } // end namespace yaml
 } // end namespace llvm
 
 LLVM_YAML_IS_SEQUENCE_VECTOR(llvm::yaml::VirtualRegisterDefinition)
 LLVM_YAML_IS_SEQUENCE_VECTOR(llvm::yaml::MachineBasicBlock)
 LLVM_YAML_IS_SEQUENCE_VECTOR(llvm::yaml::MachineStackObject)
+LLVM_YAML_IS_SEQUENCE_VECTOR(llvm::yaml::FixedMachineStackObject)
 
 namespace llvm {
 namespace yaml {
@@ -230,6 +271,7 @@ struct MachineFunction {
   // TODO: Serialize live in registers.
   // Frame information
   MachineFrameInfo FrameInfo;
+  std::vector<FixedMachineStackObject> FixedStackObjects;
   std::vector<MachineStackObject> StackObjects;
 
   std::vector<MachineBasicBlock> BasicBlocks;
@@ -246,6 +288,7 @@ template <> struct MappingTraits<MachineFunction> {
     YamlIO.mapOptional("tracksSubRegLiveness", MF.TracksSubRegLiveness);
     YamlIO.mapOptional("registers", MF.VirtualRegisters);
     YamlIO.mapOptional("frameInfo", MF.FrameInfo);
+    YamlIO.mapOptional("fixedStack", MF.FixedStackObjects);
     YamlIO.mapOptional("stack", MF.StackObjects);
     YamlIO.mapOptional("body", MF.BasicBlocks);
   }

llvm/lib/CodeGen/MIRParser/MIRParser.cpp

@@ -376,7 +376,20 @@ bool MIRParserImpl::initializeFrameInfo(MachineFrameInfo &MFI,
   MFI.setHasVAStart(YamlMFI.HasVAStart);
   MFI.setHasMustTailInVarArgFunc(YamlMFI.HasMustTailInVarArgFunc);
 
-  // Initialize the frame objects.
+  // Initialize the fixed frame objects.
+  for (const auto &Object : YamlMF.FixedStackObjects) {
+    int ObjectIdx;
+    if (Object.Type != yaml::FixedMachineStackObject::SpillSlot)
+      ObjectIdx = MFI.CreateFixedObject(Object.Size, Object.Offset,
+                                        Object.IsImmutable, Object.IsAliased);
+    else
+      ObjectIdx = MFI.CreateFixedSpillStackObject(Object.Size, Object.Offset);
+    MFI.setObjectAlignment(ObjectIdx, Object.Alignment);
+    // TODO: Store the mapping between fixed object IDs and object indices to
+    // parse fixed stack object references correctly.
+  }
+
+  // Initialize the ordinary frame objects.
   for (const auto &Object : YamlMF.StackObjects) {
     int ObjectIdx = MFI.CreateStackObject(
         Object.Size, Object.Alignment,

llvm/lib/CodeGen/MIRPrinter.cpp

@@ -157,7 +157,29 @@ void MIRPrinter::convert(yaml::MachineFrameInfo &YamlMFI,
 
 void MIRPrinter::convertStackObjects(yaml::MachineFunction &MF,
                                      const MachineFrameInfo &MFI) {
+  // Process fixed stack objects.
   unsigned ID = 0;
+  for (int I = MFI.getObjectIndexBegin(); I < 0; ++I) {
+    if (MFI.isDeadObjectIndex(I))
+      continue;
+
+    yaml::FixedMachineStackObject YamlObject;
+    YamlObject.ID = ID++;
+    YamlObject.Type = MFI.isSpillSlotObjectIndex(I)
+                          ? yaml::FixedMachineStackObject::SpillSlot
+                          : yaml::FixedMachineStackObject::DefaultType;
+    YamlObject.Offset = MFI.getObjectOffset(I);
+    YamlObject.Size = MFI.getObjectSize(I);
+    YamlObject.Alignment = MFI.getObjectAlignment(I);
+    YamlObject.IsImmutable = MFI.isImmutableObjectIndex(I);
+    YamlObject.IsAliased = MFI.isAliasedObjectIndex(I);
+    MF.FixedStackObjects.push_back(YamlObject);
+    // TODO: Store the mapping between fixed object IDs and object indices to
+    // print the fixed stack object references correctly.
+  }
+
+  // Process ordinary stack objects.
+  ID = 0;
   for (int I = 0, E = MFI.getObjectIndexEnd(); I < E; ++I) {
     if (MFI.isDeadObjectIndex(I))
       continue;

llvm/test/CodeGen/MIR/X86/fixed-stack-objects.mir

@@ -0,0 +1,35 @@
+# RUN: llc -march=x86 -start-after branch-folder -stop-after branch-folder -o /dev/null %s | FileCheck %s
+# This test ensures that the MIR parser parses fixed stack objects correctly.
+
+--- |
+
+  define i32 @test(i32 %a) #0 {
+  entry:
+    %b = alloca i32
+    store i32 %a, i32* %b
+    %c = load i32, i32* %b
+    ret i32 %c
+  }
+
+  attributes #0 = { "no-frame-pointer-elim"="false" }
+
+...
+---
+name:            test
+frameInfo:
+  stackSize:       4
+  maxAlignment:    4
+# CHECK: fixedStack:
+# CHECK-NEXT: - { id: 0, offset: 0, size: 4, alignment: 4, isImmutable: true, isAliased: false }
+fixedStack:
+  - { id: 0, offset: 0, size: 4, alignment: 4, isImmutable: true, isAliased: false }
+stack:
+  - { id: 0, offset: -8, size: 4, alignment: 4 }
+body:
+  - id:          0
+    name:        entry
+    instructions:
+      - '%eax = MOV32rm %esp, 1, _, 8, _'
+      - 'MOV32mr %esp, 1, _, 0, _, %eax'
+      - 'RETL %eax'
+...

llvm/test/CodeGen/MIR/X86/spill-slot-fixed-stack-object-aliased.mir

@@ -0,0 +1,32 @@
+# RUN: not llc -march=x86-64 -start-after branch-folder -stop-after branch-folder -o /dev/null %s 2>&1 | FileCheck %s
+
+--- |
+
+  define i32 @test(i32 %a) #0 {
+  entry:
+    %b = alloca i32
+    store i32 %a, i32* %b
+    %c = load i32, i32* %b
+    ret i32 %c
+  }
+
+  attributes #0 = { "no-frame-pointer-elim"="false" }
+
+...
+---
+name:            test
+frameInfo:
+  maxAlignment:    4
+fixedStack:
+  # CHECK: [[@LINE+1]]:63: unknown key 'isAliased'
+  - { id: 0, type: spill-slot, offset: 0, size: 4, isAliased: true }
+stack:
+  - { id: 0, offset: -12, size: 4, alignment: 4 }
+body:
+  - id:          0
+    name:        entry
+    instructions:
+      - 'MOV32mr %rsp, 1, _, -4, _, %edi'
+      - '%eax = COPY %edi'
+      - 'RETQ %eax'
+...

llvm/test/CodeGen/MIR/X86/spill-slot-fixed-stack-object-immutable.mir

@@ -0,0 +1,32 @@
+# RUN: not llc -march=x86-64 -start-after branch-folder -stop-after branch-folder -o /dev/null %s 2>&1 | FileCheck %s
+
+--- |
+
+  define i32 @test(i32 %a) #0 {
+  entry:
+    %b = alloca i32
+    store i32 %a, i32* %b
+    %c = load i32, i32* %b
+    ret i32 %c
+  }
+
+  attributes #0 = { "no-frame-pointer-elim"="false" }
+
+...
+---
+name:            test
+frameInfo:
+  maxAlignment:    4
+fixedStack:
+  # CHECK: [[@LINE+1]]:65: unknown key 'isImmutable'
+  - { id: 0, type: spill-slot, offset: 0, size: 4, isImmutable: true }
+stack:
+  - { id: 0, offset: -12, size: 4, alignment: 4 }
+body:
+  - id:          0
+    name:        entry
+    instructions:
+      - 'MOV32mr %rsp, 1, _, -4, _, %edi'
+      - '%eax = COPY %edi'
+      - 'RETQ %eax'
+...

llvm/test/CodeGen/MIR/X86/spill-slot-fixed-stack-objects.mir

@@ -0,0 +1,34 @@
+# RUN: llc -march=x86-64 -start-after branch-folder -stop-after branch-folder -o /dev/null %s | FileCheck %s
+# This test ensures that the MIR parser parses fixed stack objects correctly.
+
+--- |
+
+  define i32 @test(i32 %a) #0 {
+  entry:
+    %b = alloca i32
+    store i32 %a, i32* %b
+    %c = load i32, i32* %b
+    ret i32 %c
+  }
+
+  attributes #0 = { "no-frame-pointer-elim"="false" }
+
+...
+---
+name:            test
+frameInfo:
+  maxAlignment:    4
+# CHECK: fixedStack:
+# CHECK-NEXT: - { id: 0, type: spill-slot, offset: 0, size: 4, alignment: 4 }
+fixedStack:
+  - { id: 0, type: spill-slot, offset: 0, size: 4, alignment: 4 }
+stack:
+  - { id: 0, offset: -12, size: 4, alignment: 4 }
+body:
+  - id:          0
+    name:        entry
+    instructions:
+      - 'MOV32mr %rsp, 1, _, -4, _, %edi'
+      - '%eax = COPY %edi'
+      - 'RETQ %eax'
+...