Temporarily revert "Debug Info: Assign unique names to anonymous variables and arguments."

This reverts commit ef84c81 because fd6e8a9 needed to be reverted.

Author: adrian-prantl

lib/IRGen/IRGenSIL.cpp

@@ -295,8 +295,6 @@ class IRGenSILFunction :
   /// Keeps track of the mapping of source variables to -O0 shadow copy allocas.
   llvm::SmallDenseMap<std::pair<const SILDebugScope *, StringRef>, Address, 8>
       ShadowStackSlots;
-  llvm::SmallDenseMap<Decl *, SmallString<4>, 8> AnonymousVariables;
-  unsigned NumAnonVars = 0;
 
   /// Accumulative amount of allocated bytes on the stack. Used to limit the
   /// size for stack promoted objects.
@@ -483,26 +481,6 @@ class IRGenSILFunction :
     return foundBB->second;
   }
 
-  StringRef getOrCreateAnonymousVarName(VarDecl *Decl) {
-    llvm::SmallString<4> &Name = AnonymousVariables[Decl];
-    if (Name.empty()) {
-      {
-        llvm::raw_svector_ostream S(Name);
-        S << '_' << NumAnonVars++;
-      }
-      AnonymousVariables.insert({Decl, Name});
-    }
-    return Name;
-  }
-
-  template <class DebugVarCarryingInst>
-  StringRef getVarName(DebugVarCarryingInst *i) {
-    StringRef Name = i->getVarInfo().Name;
-    if (Name.empty() && i->getDecl())
-      return getOrCreateAnonymousVarName(i->getDecl());
-    return Name;
-  }
-
   /// At -O0, emit a shadow copy of an Address in an alloca, so the
   /// register allocator doesn't elide the dbg.value intrinsic when
   /// register pressure is high.  There is a trade-off to this: With
@@ -609,8 +587,6 @@ class IRGenSILFunction :
 
   void emitFunctionArgDebugInfo(SILBasicBlock *BB);
 
-  void emitDebugInfoForAllocStack(AllocStackInst *i, const TypeInfo &type,
-                                  llvm::Value *addr);
   void visitAllocStackInst(AllocStackInst *i);
   void visitAllocRefInst(AllocRefInst *i);
   void visitAllocRefDynamicInst(AllocRefDynamicInst *i);
@@ -2973,7 +2949,7 @@ void IRGenSILFunction::visitDebugValueInst(DebugValueInst *i) {
   if (isa<SILUndef>(SILVal))
     return;
 
-  StringRef Name = getVarName(i);
+  StringRef Name = i->getVarInfo().Name;
   DebugTypeInfo DbgTy;
   SILType SILTy = SILVal.getType();
   if (VarDecl *Decl = i->getDecl())
@@ -3007,7 +2983,7 @@ void IRGenSILFunction::visitDebugValueAddrInst(DebugValueAddrInst *i) {
   if (isa<SILUndef>(SILVal))
     return;
 
-  StringRef Name = getVarName(i);
+  StringRef Name = i->getVarInfo().Name;
   auto Addr = getLoweredAddress(SILVal).getAddress();
   DebugTypeInfo DbgTy(Decl, Decl->getType(), getTypeInfo(SILVal.getType()));
   // Put the value into a stack slot at -Onone and emit a debug intrinsic.
@@ -3255,23 +3231,25 @@ static bool tryDeferFixedSizeBufferInitialization(IRGenSILFunction &IGF,
   return false;
 }
 
-void IRGenSILFunction::emitDebugInfoForAllocStack(AllocStackInst *i,
-                                                  const TypeInfo &type,
-                                                  llvm::Value *addr) {
+static void emitDebugDeclarationForAllocStack(IRGenSILFunction &IGF,
+                                              AllocStackInst *i,
+                                              const TypeInfo &type,
+                                              llvm::Value *addr) {
   VarDecl *Decl = i->getDecl();
-  if (IGM.DebugInfo && Decl) {
+  if (IGF.IGM.DebugInfo && Decl) {
     auto *Pattern = Decl->getParentPattern();
     if (!Pattern || !Pattern->isImplicit()) {
       auto DbgTy = DebugTypeInfo(Decl, type);
       // Discard any inout or lvalue qualifiers. Since the object itself
       // is stored in the alloca, emitting it as a reference type would
       // be wrong.
       DbgTy.unwrapLValueOrInOutType();
-      StringRef Name = getVarName(i);
-      if (auto DS = i->getDebugScope()) {
-        assert(DS->SILFn == CurSILFn || DS->InlinedCallSite);
-        emitDebugVariableDeclaration(addr, DbgTy, DS, Name,
-                                     i->getVarInfo().ArgNo);
+      auto Name = i->getVarInfo().Name.empty() ? "_" : i->getVarInfo().Name;
+      auto DS = i->getDebugScope();
+      if (DS) {
+        assert(DS->SILFn == IGF.CurSILFn || DS->InlinedCallSite);
+        IGF.emitDebugVariableDeclaration(addr, DbgTy, DS, Name,
+                                         i->getVarInfo().ArgNo);
       }
     }
   }
@@ -3285,7 +3263,7 @@ void IRGenSILFunction::visitAllocStackInst(swift::AllocStackInst *i) {
   StringRef dbgname;
 # ifndef NDEBUG
   // If this is a DEBUG build, use pretty names for the LLVM IR.
-  dbgname = getVarName(i);
+  dbgname = i->getVarInfo().Name;
 # endif
 
   (void) Decl;
@@ -3302,8 +3280,10 @@ void IRGenSILFunction::visitAllocStackInst(swift::AllocStackInst *i) {
   auto addr = type.allocateStack(*this,
                                  i->getElementType(),
                                  dbgname);
-
-  emitDebugInfoForAllocStack(i, type, addr.getAddress().getAddress());
+  
+  emitDebugDeclarationForAllocStack(*this, i, type,
+                                    addr.getAddress().getAddress());
+  
   setLoweredAddress(i->getContainerResult(), addr.getContainer());
   setLoweredAddress(i->getAddressResult(), addr.getAddress());
 }
@@ -3397,7 +3377,7 @@ void IRGenSILFunction::visitAllocBoxInst(swift::AllocBoxInst *i) {
 
   // Derive name from SIL location.
   VarDecl *Decl = i->getDecl();
-  StringRef Name = getVarName(i);
+  StringRef Name = i->getVarInfo().Name;
   StringRef DbgName =
 # ifndef NDEBUG
     // If this is a DEBUG build, use pretty names for the LLVM IR.
@@ -4352,15 +4332,15 @@ void IRGenSILFunction::visitWitnessMethodInst(swift::WitnessMethodInst *i) {
 
 void IRGenSILFunction::setAllocatedAddressForBuffer(SILValue v,
                                                 const Address &allocedAddress) {
-  assert(getLoweredValue(v).kind ==
-             LoweredValue::Kind::UnallocatedAddressInBuffer &&
-         "not an unallocated address");
-
+  assert(getLoweredValue(v).kind == LoweredValue::Kind::UnallocatedAddressInBuffer
+         && "not an unallocated address");
+  
   overwriteLoweredAddress(v, allocedAddress);
   // Emit the debug info for the variable if any.
   if (auto allocStack = dyn_cast<AllocStackInst>(v)) {
-    emitDebugInfoForAllocStack(allocStack, getTypeInfo(v.getType()),
-                               allocedAddress.getAddress());
+    emitDebugDeclarationForAllocStack(*this, allocStack,
+                                      getTypeInfo(v.getType()),
+                                      allocedAddress.getAddress());
   }
 }
 

lib/SILGen/SILGenProlog.cpp

@@ -324,17 +324,9 @@ struct ArgumentInitVisitor :
     ++ArgNo;
     auto PD = P->getDecl();
     if (!PD->hasName()) {
-      ManagedValue argrv = makeArgument(P->getType(), &*f.begin(), PD);
-      // Emit debug information for the argument.
-      SILLocation loc(PD);
-      loc.markAsPrologue();
-      if (argrv.getType().isAddress())
-        gen.B.createDebugValueAddr(loc, argrv.getValue(), {PD->isLet(), ArgNo});
-      else
-        gen.B.createDebugValue(loc, argrv.getValue(), {PD->isLet(), ArgNo});
-
       // A value bound to _ is unused and can be immediately released.
       Scope discardScope(gen.Cleanups, CleanupLocation(P));
+      makeArgument(P->getType(), &*f.begin(), PD);
       // Popping the scope destroys the value.
     } else {
       makeArgumentIntoBinding(P->getType(), &*f.begin(), PD);

test/DebugInfo/anonymous.swift

@@ -1,10 +1,22 @@
 // RUN: %target-swift-frontend -primary-file %s -emit-ir -g -o - | FileCheck %s
 
-// CHECK: !DILocalVariable(name: "_0", arg: 1
-// CHECK: !DILocalVariable(name: "_1", arg: 2
-// CHECK: !DILocalVariable(name: "_2", arg: 3
-// CHECK: !DILocalVariable(name: "x4", arg: 4
+// Don't crash when emitting debug info for anonymous variables.
+// CHECK: !DILocalVariable(name: "_"
 
-public func fourth<T>(_: T, _: T, _: T, x4 : T) -> T {
-  return x4
+func markUsed<T>(t: T) {}
+
+protocol F_ {
+  func successor() -> Self
+}
+
+protocol F : F_ {
+  func ~> (_: Self, _: (_Distance, (Self))) -> Int64
+}
+
+struct _Distance {}
+
+func ~> <I: F_>(self_:I, _: (_Distance, (I))) -> Int64 {
+  self_.successor()
+  markUsed("F")
+  return 0
 }