MIR Serialization: Serialize references from the stack objects to named allocas.

This commit serializes the references to the named LLVM alloca instructions from
the stack objects in the machine frame info. This commit adds a field 'Name' to
the struct 'yaml::MachineStackObject'. This new field is used to store the name
of the alloca instruction when the alloca is present and when it has a name.

llvm-svn: 242339

llvm/include/llvm/CodeGen/MIRYamlMapping.h

@@ -132,8 +132,9 @@ template <> struct MappingTraits<MachineBasicBlock> {
 /// objects (Serialize local objects).
 struct MachineStackObject {
   enum ObjectType { DefaultType, SpillSlot, VariableSized };
-  // TODO: Serialize LLVM alloca reference.
   unsigned ID;
+  StringValue Name;
+  // TODO: Serialize unnamed LLVM alloca reference.
   ObjectType Type = DefaultType;
   int64_t Offset = 0;
   uint64_t Size = 0;
@@ -151,6 +152,8 @@ template <> struct ScalarEnumerationTraits<MachineStackObject::ObjectType> {
 template <> struct MappingTraits<MachineStackObject> {
   static void mapping(yaml::IO &YamlIO, MachineStackObject &Object) {
     YamlIO.mapRequired("id", Object.ID);
+    YamlIO.mapOptional("name", Object.Name,
+                       StringValue()); // Don't print out an empty name.
     YamlIO.mapOptional(
         "type", Object.Type,
         MachineStackObject::DefaultType); // Don't print the default type.

llvm/lib/CodeGen/MIRParser/MIRParser.cpp

@@ -108,7 +108,7 @@ public:
                          const yaml::MachineFunction &YamlMF,
                          DenseMap<unsigned, unsigned> &VirtualRegisterSlots);
 
-  bool initializeFrameInfo(MachineFrameInfo &MFI,
+  bool initializeFrameInfo(const Function &F, MachineFrameInfo &MFI,
                            const yaml::MachineFunction &YamlMF);
 
 private:
@@ -264,7 +264,7 @@ bool MIRParserImpl::initializeMachineFunction(MachineFunction &MF) {
   if (initializeRegisterInfo(MF, MF.getRegInfo(), YamlMF,
                              PFS.VirtualRegisterSlots))
     return true;
-  if (initializeFrameInfo(*MF.getFrameInfo(), YamlMF))
+  if (initializeFrameInfo(*MF.getFunction(), *MF.getFrameInfo(), YamlMF))
     return true;
 
   const auto &F = *MF.getFunction();
@@ -366,7 +366,8 @@ bool MIRParserImpl::initializeRegisterInfo(
   return false;
 }
 
-bool MIRParserImpl::initializeFrameInfo(MachineFrameInfo &MFI,
+bool MIRParserImpl::initializeFrameInfo(const Function &F,
+                                        MachineFrameInfo &MFI,
                                         const yaml::MachineFunction &YamlMF) {
   const yaml::MachineFrameInfo &YamlMFI = YamlMF.FrameInfo;
   MFI.setFrameAddressIsTaken(YamlMFI.IsFrameAddressTaken);
@@ -400,13 +401,23 @@ bool MIRParserImpl::initializeFrameInfo(MachineFrameInfo &MFI,
   // Initialize the ordinary frame objects.
   for (const auto &Object : YamlMF.StackObjects) {
     int ObjectIdx;
+    const AllocaInst *Alloca = nullptr;
+    const yaml::StringValue &Name = Object.Name;
+    if (!Name.Value.empty()) {
+      Alloca = dyn_cast_or_null<AllocaInst>(
+          F.getValueSymbolTable().lookup(Name.Value));
+      if (!Alloca)
+        return error(Name.SourceRange.Start,
+                     "alloca instruction named '" + Name.Value +
+                         "' isn't defined in the function '" + F.getName() +
+                         "'");
+    }
     if (Object.Type == yaml::MachineStackObject::VariableSized)
-      ObjectIdx =
+      ObjectIdx = MFI.CreateVariableSizedObject(Object.Alignment, Alloca);
-          MFI.CreateVariableSizedObject(Object.Alignment, /*Alloca=*/nullptr);
     else
       ObjectIdx = MFI.CreateStackObject(
           Object.Size, Object.Alignment,
-          Object.Type == yaml::MachineStackObject::SpillSlot);
+          Object.Type == yaml::MachineStackObject::SpillSlot, Alloca);
     MFI.setObjectOffset(ObjectIdx, Object.Offset);
     // TODO: Store the mapping between object IDs and object indices to parse
     // stack object references correctly.

llvm/lib/CodeGen/MIRPrinter.cpp

@@ -19,6 +19,7 @@
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/MIRYamlMapping.h"
 #include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/Instructions.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/ModuleSlotTracker.h"
 #include "llvm/Support/MemoryBuffer.h"
@@ -199,6 +200,9 @@ void MIRPrinter::convertStackObjects(yaml::MachineFunction &MF,
 
     yaml::MachineStackObject YamlObject;
     YamlObject.ID = ID++;
+    if (const auto *Alloca = MFI.getObjectAllocation(I))
+      YamlObject.Name.Value =
+          Alloca->hasName() ? Alloca->getName() : "<unnamed alloca>";
     YamlObject.Type = MFI.isSpillSlotObjectIndex(I)
                           ? yaml::MachineStackObject::SpillSlot
                           : MFI.isVariableSizedObjectIndex(I)

llvm/test/CodeGen/MIR/X86/stack-object-invalid-name.mir

@@ -0,0 +1,30 @@
+# RUN: not llc -march=x86-64 -start-after branch-folder -stop-after branch-folder -o /dev/null %s 2>&1 | FileCheck %s
+# This test ensures that the MIR parser reports an error when it encounters a
+# stack object with a name that can't be associated with an alloca instruction.
+
+--- |
+
+  define i32 @test(i32 %a) {
+  entry:
+    %b = alloca i32
+    store i32 %a, i32* %b
+    %c = load i32, i32* %b
+    ret i32 %c
+  }
+
+...
+---
+name:            test
+frameInfo:
+  maxAlignment:  4
+stack:
+  # CHECK: [[@LINE+1]]:20: alloca instruction named 'x' isn't defined in the function 'test'
+  - { id: 0, name: x, offset: -12, size: 4, alignment: 4 }
+body:
+  - id:          0
+    name:        entry
+    instructions:
+      - 'MOV32mr %rsp, 1, _, -4, _, %edi'
+      - '%eax = MOV32rm %rsp, 1, _, -4, _'
+      - 'RETQ %eax'
+...

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

@@ -21,12 +21,12 @@ name:            test
 frameInfo:
   maxAlignment:    8
 # CHECK: stack:
-# CHECK-NEXT: - { id: 0, offset: -12, size: 4, alignment: 4 }
+# CHECK-NEXT: - { id: 0, name: b, offset: -12, size: 4, alignment: 4 }
-# CHECK-NEXT: - { id: 1, offset: -24, size: 8, alignment: 8 }
+# CHECK-NEXT: - { id: 1, name: x, offset: -24, size: 8, alignment: 8 }
 # CHECK-NEXT: - { id: 2, type: spill-slot, offset: -32, size: 4, alignment: 4 }
 stack:
-  - { id: 0, offset: -12, size: 4, alignment: 4 }
+  - { id: 0, name: b, offset: -12, size: 4, alignment: 4 }
-  - { id: 1, offset: -24, size: 8, alignment: 8 }
+  - { id: 1, name: x, offset: -24, size: 8, alignment: 8 }
   - { id: 2, type: spill-slot, offset: -32, size: 4, alignment: 4 }
 body:
   - id:          0

llvm/test/CodeGen/MIR/X86/variable-sized-stack-objects.mir

@@ -26,11 +26,11 @@ frameInfo:
 # CHECK: stack:
 # CHECK-NEXT: - { id: 0, offset: -20, size: 4, alignment: 4 }
 # CHECK-NEXT: - { id: 1, offset: -32, size: 8, alignment: 8 }
-# CHECK-NEXT: - { id: 2, type: variable-sized, offset: -32, alignment: 1 }
+# CHECK-NEXT: - { id: 2, name: y, type: variable-sized, offset: -32, alignment: 1 }
 stack:
   - { id: 0, offset: -20, size: 4, alignment: 4 }
   - { id: 1, offset: -32, size: 8, alignment: 8 }
-  - { id: 2, type: variable-sized, offset: -32, alignment: 1 }
+  - { id: 2, name: y, type: variable-sized, offset: -32, alignment: 1 }
 body:
   - id:          0
     name:        entry