Add MachineModuleInfo constructor with external MCContext

Adds a constructor to MachineModuleInfo and MachineModuleInfoWapperPass that
takes an external MCContext. If provided, the external context will be used
throughout codegen instead of MMI's default one.

This enables external drivers to take ownership of data put on the MMI's context
during codegen. The internal context is used otherwise and destroyed upon
finish.

Differential Revision: https://reviews.llvm.org/D91313

1 files changed, 17 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/MachineModuleInfo.cpp b/llvm/lib/CodeGen/MachineModuleInfo.cpp
index be08f0ae3117..f75acbb2494b 100644
--- a/llvm/lib/CodeGen/MachineModuleInfo.cpp
+++ b/llvm/lib/CodeGen/MachineModuleInfo.cpp
@@ -170,6 +170,7 @@ void MachineModuleInfo::finalize() {
   AddrLabelSymbols = nullptr;
 
   Context.reset();
+  // We don't clear the ExternalContext.
 
   delete ObjFileMMI;
   ObjFileMMI = nullptr;
@@ -187,6 +188,7 @@ MachineModuleInfo::MachineModuleInfo(MachineModuleInfo &&MMI)
   HasSplitStack = MMI.HasSplitStack;
   HasNosplitStack = MMI.HasNosplitStack;
   AddrLabelSymbols = MMI.AddrLabelSymbols;
+  ExternalContext = MMI.ExternalContext;
   TheModule = MMI.TheModule;
 }
 
@@ -196,6 +198,14 @@ MachineModuleInfo::MachineModuleInfo(const LLVMTargetMachine *TM)
   initialize();
 }
 
+MachineModuleInfo::MachineModuleInfo(const LLVMTargetMachine *TM,
+                                     MCContext *ExtContext)
+    : TM(*TM), Context(TM->getMCAsmInfo(), TM->getMCRegisterInfo(),
+                       TM->getObjFileLowering(), nullptr, nullptr, false),
+      ExternalContext(ExtContext) {
+  initialize();
+}
+
 MachineModuleInfo::~MachineModuleInfo() { finalize(); }
 
 //===- Address of Block Management ----------------------------------------===//
@@ -204,7 +214,7 @@ ArrayRef<MCSymbol *>
 MachineModuleInfo::getAddrLabelSymbolToEmit(const BasicBlock *BB) {
   // Lazily create AddrLabelSymbols.
   if (!AddrLabelSymbols)
-    AddrLabelSymbols = new MMIAddrLabelMap(Context);
+    AddrLabelSymbols = new MMIAddrLabelMap(getContext());
  return AddrLabelSymbols->getAddrLabelSymbolToEmit(const_cast<BasicBlock*>(BB));
 }
 
@@ -296,6 +306,12 @@ MachineModuleInfoWrapperPass::MachineModuleInfoWrapperPass(
   initializeMachineModuleInfoWrapperPassPass(*PassRegistry::getPassRegistry());
 }
 
+MachineModuleInfoWrapperPass::MachineModuleInfoWrapperPass(
+    const LLVMTargetMachine *TM, MCContext *ExtContext)
+    : ImmutablePass(ID), MMI(TM, ExtContext) {
+  initializeMachineModuleInfoWrapperPassPass(*PassRegistry::getPassRegistry());
+}
+
 // Handle the Pass registration stuff necessary to use DataLayout's.
 INITIALIZE_PASS(MachineModuleInfoWrapperPass, "machinemoduleinfo",
                 "Machine Module Information", false, false)