Fix unused lambda capture in a non-asserts build

For locally scoped lambdas like this there's no particular benefit to
explicitly listing captures - or avoiding capturing this. Switch to [&]
and make it all easier to maintain.

(& driveby change std::function to llvm::function_ref)

Author: dwblaikie

llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp

@@ -775,10 +775,7 @@ DIE *DwarfCompileUnit::constructVariableDIEImpl(const DbgVariable &DV,
     DIExpressionCursor Cursor(Expr);
     const TargetRegisterInfo &TRI = *Asm->MF->getSubtarget().getRegisterInfo();
 
-    // Declare the TargetMachine locally so we don't need to capture `this` in
-    // the lambda.
-    TargetMachine &TM = Asm->TM;
-    auto AddEntry = [&DwarfExpr, &TRI, &TM](const DbgValueLocEntry &Entry,
+    auto AddEntry = [&](const DbgValueLocEntry &Entry,
                                             DIExpressionCursor &Cursor) {
       if (Entry.isLocation()) {
         if (!DwarfExpr.addMachineRegExpression(TRI, Cursor,
@@ -797,7 +794,7 @@ DIE *DwarfCompileUnit::constructVariableDIEImpl(const DbgVariable &DV,
         TargetIndexLocation Loc = Entry.getTargetIndexLocation();
         // TODO TargetIndexLocation is a target-independent. Currently only the
         // WebAssembly-specific encoding is supported.
-        assert(TM.getTargetTriple().isWasm());
+        assert(Asm->TM.getTargetTriple().isWasm());
         DwarfExpr.addWasmLocation(Loc.Index, static_cast<uint64_t>(Loc.Offset));
       } else {
         llvm_unreachable("Unsupported Entry type.");
@@ -807,7 +804,7 @@ DIE *DwarfCompileUnit::constructVariableDIEImpl(const DbgVariable &DV,
 
     DwarfExpr.addExpression(
         std::move(Cursor),
-        [&AddEntry, &DVal](unsigned Idx, DIExpressionCursor &Cursor) -> bool {
+        [&](unsigned Idx, DIExpressionCursor &Cursor) -> bool {
           return AddEntry(DVal->getLocEntries()[Idx], Cursor);
         });
 

llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp

@@ -473,7 +473,7 @@ void DwarfExpression::addExpression(DIExpressionCursor &&ExprCursor,
 
 void DwarfExpression::addExpression(
     DIExpressionCursor &&ExprCursor,
-    std::function<bool(unsigned, DIExpressionCursor &)> InsertArg) {
+    llvm::function_ref<bool(unsigned, DIExpressionCursor &)> InsertArg) {
   // Entry values can currently only cover the initial register location,
   // and not any other parts of the following DWARF expression.
   assert(!IsEmittingEntryValue && "Can't emit entry value around expression");

llvm/lib/CodeGen/AsmPrinter/DwarfExpression.h

@@ -349,7 +349,7 @@ class DwarfExpression {
                      unsigned FragmentOffsetInBits = 0);
   void
   addExpression(DIExpressionCursor &&Expr,
-                std::function<bool(unsigned, DIExpressionCursor &)> InsertArg);
+                llvm::function_ref<bool(unsigned, DIExpressionCursor &)> InsertArg);
 
   /// If applicable, emit an empty DW_OP_piece / DW_OP_bit_piece to advance to
   /// the fragment described by \c Expr.