Allow MachineFunction to obtain non-const Function (to enable MIR-level debugify)

Summary:
To debugify MIR, we need to be able to create metadata and to do that, we
need a non-const Module. However, MachineFunction only had a const reference
to the Function preventing this.

Reviewers: aprantl, bogner

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77439

Author: dsandersllvm

llvm/include/llvm/CodeGen/MachineFunction.h

@@ -224,7 +224,7 @@ struct LandingPadInfo {
 };
 
 class MachineFunction {
-  const Function &F;
+  Function &F;
   const LLVMTargetMachine &Target;
   const TargetSubtargetInfo *STI;
   MCContext &Ctx;
@@ -435,7 +435,7 @@ class MachineFunction {
   using VariableDbgInfoMapTy = SmallVector<VariableDbgInfo, 4>;
   VariableDbgInfoMapTy VariableDbgInfos;
 
-  MachineFunction(const Function &F, const LLVMTargetMachine &Target,
+  MachineFunction(Function &F, const LLVMTargetMachine &Target,
                   const TargetSubtargetInfo &STI, unsigned FunctionNum,
                   MachineModuleInfo &MMI);
   MachineFunction(const MachineFunction &) = delete;
@@ -483,6 +483,9 @@ class MachineFunction {
   /// Return the DataLayout attached to the Module associated to this MF.
   const DataLayout &getDataLayout() const;
 
+  /// Return the LLVM function that this machine code represents
+  Function &getFunction() { return F; }
+
   /// Return the LLVM function that this machine code represents
   const Function &getFunction() const { return F; }
 

llvm/include/llvm/CodeGen/MachineModuleInfo.h

@@ -165,9 +165,9 @@ class MachineModuleInfo {
 
   /// Returns the MachineFunction constructed for the IR function \p F.
   /// Creates a new MachineFunction if none exists yet.
-  MachineFunction &getOrCreateMachineFunction(const Function &F);
+  MachineFunction &getOrCreateMachineFunction(Function &F);
 
-  /// \bried Returns the MachineFunction associated to IR function \p F if there
+  /// \brief Returns the MachineFunction associated to IR function \p F if there
   /// is one, otherwise nullptr.
   MachineFunction *getMachineFunction(const Function &F) const;
 

llvm/lib/CodeGen/MachineFunction.cpp

@@ -133,8 +133,7 @@ static inline unsigned getFnStackAlignment(const TargetSubtargetInfo *STI,
   return STI->getFrameLowering()->getStackAlign().value();
 }
 
-MachineFunction::MachineFunction(const Function &F,
-                                 const LLVMTargetMachine &Target,
+MachineFunction::MachineFunction(Function &F, const LLVMTargetMachine &Target,
                                  const TargetSubtargetInfo &STI,
                                  unsigned FunctionNum, MachineModuleInfo &mmi)
     : F(F), Target(Target), STI(&STI), Ctx(mmi.getContext()), MMI(mmi) {

llvm/lib/CodeGen/MachineModuleInfo.cpp

@@ -225,8 +225,7 @@ MachineModuleInfo::getMachineFunction(const Function &F) const {
   return I != MachineFunctions.end() ? I->second.get() : nullptr;
 }
 
-MachineFunction &
-MachineModuleInfo::getOrCreateMachineFunction(const Function &F) {
+MachineFunction &MachineModuleInfo::getOrCreateMachineFunction(Function &F) {
   // Shortcut for the common case where a sequence of MachineFunctionPasses
   // all query for the same Function.
   if (LastRequest == &F)