[Ignore Expressions] Fix performance regression by inlining `Ignore*SingleStep`

[eduucaldas]

Summary

Mentioned performance regression:
http://llvm-compile-time-tracker.com/compare.php?from=8d64df9f139038b48344dd9f1f20a38b22aba8c9&to=81aa66f65f504af18982baa078a5f3f7d2aa88fa&stat=instructions

We also add a const version of IgnoreExprNodes

[riccibruno]

Thanks!

clang/include/clang/AST/IgnoreExpr.h

 //===--- IgnoreExpr.h - Ignore intermediate Expressions -----------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
 // This file defines common functions to ignore intermediate expression nodes
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_CLANG_AST_IGNOREEXPR_H
 #define LLVM_CLANG_AST_IGNOREEXPR_H
 
 #include "clang/AST/Expr.h"
+#include "clang/AST/ExprCXX.h"
 
 namespace clang {
 namespace detail {
 /// Given an expression E and functions Fn_1,...,Fn_n : Expr * -> Expr *,
 /// Return Fn_n(...(Fn_1(E)))
 inline Expr *IgnoreExprNodesImpl(Expr *E) { return E; }
 template <typename FnTy, typename... FnTys>
 Expr *IgnoreExprNodesImpl(Expr *E, FnTy &&Fn, FnTys &&... Fns) {
   return IgnoreExprNodesImpl(Fn(E), std::forward<FnTys>(Fns)...);
 }
 } // namespace detail
 
 /// Given an expression E and functions Fn_1,...,Fn_n : Expr * -> Expr *,
 /// Recursively apply each of the functions to E until reaching a fixed point.
 /// Note that a null E is valid; in this case nothing is done.
 template <typename... FnTys> Expr *IgnoreExprNodes(Expr *E, FnTys &&... Fns) {
   Expr *LastE = nullptr;
   while (E != LastE) {
     LastE = E;
     E = detail::IgnoreExprNodesImpl(E, std::forward<FnTys>(Fns)...);
   }
   return E;
 }
 
-Expr *IgnoreImplicitCastsSingleStep(Expr *E);
+template <typename... FnTys>
+const Expr *IgnoreExprNodes(const Expr *E, FnTys &&...Fns) {
+  return const_cast<Expr *>(IgnoreExprNodes(E, std::forward<FnTys>(Fns)...));
+}
+
+inline Expr *IgnoreImplicitCastsSingleStep(Expr *E) {
+  if (auto *ICE = dyn_cast<ImplicitCastExpr>(E))
+    return ICE->getSubExpr();
+
+  if (auto *FE = dyn_cast<FullExpr>(E))
+    return FE->getSubExpr();
+
+  return E;
+}
+
+inline Expr *IgnoreImplicitCastsExtraSingleStep(Expr *E) {
+  // FIXME: Skip MaterializeTemporaryExpr and SubstNonTypeTemplateParmExpr in
+  // addition to what IgnoreImpCasts() skips to account for the current
+  // behaviour of IgnoreParenImpCasts().
+  Expr *SubE = IgnoreImplicitCastsSingleStep(E);
+  if (SubE != E)
+    return SubE;
+
+  if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(E))
+    return MTE->getSubExpr();
+
+  if (auto *NTTP = dyn_cast<SubstNonTypeTemplateParmExpr>(E))
+    return NTTP->getReplacement();
+
+  return E;
+}
+
+inline Expr *IgnoreCastsSingleStep(Expr *E) {
+  if (auto *CE = dyn_cast<CastExpr>(E))
+    return CE->getSubExpr();
+
+  if (auto *FE = dyn_cast<FullExpr>(E))
+    return FE->getSubExpr();
+
+  if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(E))
+    return MTE->getSubExpr();
+
+  if (auto *NTTP = dyn_cast<SubstNonTypeTemplateParmExpr>(E))
+    return NTTP->getReplacement();
+
+  return E;
+}
+
+inline Expr *IgnoreLValueCastsSingleStep(Expr *E) {
+  // Skip what IgnoreCastsSingleStep skips, except that only
+  // lvalue-to-rvalue casts are skipped.
+  if (auto *CE = dyn_cast<CastExpr>(E))
+    if (CE->getCastKind() != CK_LValueToRValue)
+      return E;
+
+  return IgnoreCastsSingleStep(E);
+}
+
+inline Expr *IgnoreBaseCastsSingleStep(Expr *E) {
+  if (auto *CE = dyn_cast<CastExpr>(E))
+    if (CE->getCastKind() == CK_DerivedToBase ||
+        CE->getCastKind() == CK_UncheckedDerivedToBase ||
+        CE->getCastKind() == CK_NoOp)
+      return CE->getSubExpr();
+
+  return E;
+}
+
+inline Expr *IgnoreImplicitSingleStep(Expr *E) {
+  Expr *SubE = IgnoreImplicitCastsSingleStep(E);
+  if (SubE != E)
+    return SubE;
+
+  if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(E))
+    return MTE->getSubExpr();
+
+  if (auto *BTE = dyn_cast<CXXBindTemporaryExpr>(E))
+    return BTE->getSubExpr();
 
-Expr *IgnoreImplicitCastsExtraSingleStep(Expr *E);
+  return E;
+}
 
-Expr *IgnoreCastsSingleStep(Expr *E);
+inline Expr *IgnoreImplicitAsWrittenSingleStep(Expr *E) {
+  if (auto *ICE = dyn_cast<ImplicitCastExpr>(E))
+    return ICE->getSubExprAsWritten();
 
-Expr *IgnoreLValueCastsSingleStep(Expr *E);
+  return IgnoreImplicitSingleStep(E);
+}
 
-Expr *IgnoreBaseCastsSingleStep(Expr *E);
+inline Expr *IgnoreParensOnlySingleStep(Expr *E) {
+  if (auto *PE = dyn_cast<ParenExpr>(E))
+    return PE->getSubExpr();
+  return E;
+}
 
-Expr *IgnoreImplicitSingleStep(Expr *E);
+inline Expr *IgnoreParensSingleStep(Expr *E) {
+  if (auto *PE = dyn_cast<ParenExpr>(E))
+    return PE->getSubExpr();
+
+  if (auto *UO = dyn_cast<UnaryOperator>(E)) {
+    if (UO->getOpcode() == UO_Extension)
+      return UO->getSubExpr();
+  }
 
-Expr *IgnoreImplicitAsWrittenSingleStep(Expr *E);
+  else if (auto *GSE = dyn_cast<GenericSelectionExpr>(E)) {
+    if (!GSE->isResultDependent())
+      return GSE->getResultExpr();
+  }
 
-Expr *IgnoreParensOnlySingleStep(Expr *E);
+  else if (auto *CE = dyn_cast<ChooseExpr>(E)) {
+    if (!CE->isConditionDependent())
+      return CE->getChosenSubExpr();
+  }
 
-Expr *IgnoreParensSingleStep(Expr *E);
+  return E;
+}
 
 } // namespace clang
 
 #endif // LLVM_CLANG_AST_IGNOREEXPR_H

clang/lib/AST/CMakeLists.txt

add_clang_library(clangAST
   ExprClassification.cpp
   ExprConcepts.cpp
   ExprConstant.cpp
   ExprCXX.cpp
   ExprObjC.cpp
   ExternalASTMerger.cpp
   ExternalASTSource.cpp
   FormatString.cpp
-  IgnoreExpr.cpp
   InheritViz.cpp
   Interp/ByteCodeEmitter.cpp
   Interp/ByteCodeExprGen.cpp
   Interp/ByteCodeGenError.cpp
   Interp/ByteCodeStmtGen.cpp
   Interp/Context.cpp
   Interp/Descriptor.cpp
   Interp/Disasm.cpp

clang/lib/AST/IgnoreExpr.cpp

-//===--- IgnoreExpr.cpp - Ignore intermediate Expressions -----------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-//
-// This file implements common functions to ignore intermediate expression nodes
-//
-//===----------------------------------------------------------------------===//
-
-#include "clang/AST/IgnoreExpr.h"
-#include "clang/AST/Expr.h"
-#include "clang/AST/ExprCXX.h"
-
-using namespace clang;
-
-Expr *clang::IgnoreImplicitCastsSingleStep(Expr *E) {
-  if (auto *ICE = dyn_cast<ImplicitCastExpr>(E))
-    return ICE->getSubExpr();
-
-  if (auto *FE = dyn_cast<FullExpr>(E))
-    return FE->getSubExpr();
-
-  return E;
-}
-
-Expr *clang::IgnoreImplicitCastsExtraSingleStep(Expr *E) {
-  // FIXME: Skip MaterializeTemporaryExpr and SubstNonTypeTemplateParmExpr in
-  // addition to what IgnoreImpCasts() skips to account for the current
-  // behaviour of IgnoreParenImpCasts().
-  Expr *SubE = IgnoreImplicitCastsSingleStep(E);
-  if (SubE != E)
-    return SubE;
-
-  if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(E))
-    return MTE->getSubExpr();
-
-  if (auto *NTTP = dyn_cast<SubstNonTypeTemplateParmExpr>(E))
-    return NTTP->getReplacement();
-
-  return E;
-}
-
-Expr *clang::IgnoreCastsSingleStep(Expr *E) {
-  if (auto *CE = dyn_cast<CastExpr>(E))
-    return CE->getSubExpr();
-
-  if (auto *FE = dyn_cast<FullExpr>(E))
-    return FE->getSubExpr();
-
-  if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(E))
-    return MTE->getSubExpr();
-
-  if (auto *NTTP = dyn_cast<SubstNonTypeTemplateParmExpr>(E))
-    return NTTP->getReplacement();
-
-  return E;
-}
-
-Expr *clang::IgnoreLValueCastsSingleStep(Expr *E) {
-  // Skip what IgnoreCastsSingleStep skips, except that only
-  // lvalue-to-rvalue casts are skipped.
-  if (auto *CE = dyn_cast<CastExpr>(E))
-    if (CE->getCastKind() != CK_LValueToRValue)
-      return E;
-
-  return IgnoreCastsSingleStep(E);
-}
-
-Expr *clang::IgnoreBaseCastsSingleStep(Expr *E) {
-  if (auto *CE = dyn_cast<CastExpr>(E))
-    if (CE->getCastKind() == CK_DerivedToBase ||
-        CE->getCastKind() == CK_UncheckedDerivedToBase ||
-        CE->getCastKind() == CK_NoOp)
-      return CE->getSubExpr();
-
-  return E;
-}
-
-Expr *clang::IgnoreImplicitSingleStep(Expr *E) {
-  Expr *SubE = IgnoreImplicitCastsSingleStep(E);
-  if (SubE != E)
-    return SubE;
-
-  if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(E))
-    return MTE->getSubExpr();
-
-  if (auto *BTE = dyn_cast<CXXBindTemporaryExpr>(E))
-    return BTE->getSubExpr();
-
-  return E;
-}
-
-Expr *clang::IgnoreImplicitAsWrittenSingleStep(Expr *E) {
-  if (auto *ICE = dyn_cast<ImplicitCastExpr>(E))
-    return ICE->getSubExprAsWritten();
-
-  return IgnoreImplicitSingleStep(E);
-}
-
-Expr *clang::IgnoreParensOnlySingleStep(Expr *E) {
-  if (auto *PE = dyn_cast<ParenExpr>(E))
-    return PE->getSubExpr();
-  return E;
-}
-
-Expr *clang::IgnoreParensSingleStep(Expr *E) {
-  if (auto *PE = dyn_cast<ParenExpr>(E))
-    return PE->getSubExpr();
-
-  if (auto *UO = dyn_cast<UnaryOperator>(E)) {
-    if (UO->getOpcode() == UO_Extension)
-      return UO->getSubExpr();
-  }
-
-  else if (auto *GSE = dyn_cast<GenericSelectionExpr>(E)) {
-    if (!GSE->isResultDependent())
-      return GSE->getResultExpr();
-  }
-
-  else if (auto *CE = dyn_cast<ChooseExpr>(E)) {
-    if (!CE->isConditionDependent())
-      return CE->getChosenSubExpr();
-  }
-
-  return E;
-}