[clang] [clang-repl] Simplify the value printing logic to enable out-of-process. (PR #107737)

[Jun Zhang via cfe-commits]

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@@ -0,0 +1,400 @@
+//===--- InterpreterValuePrinter.cpp - Value printing utils -----*- C++ -*-===//
+//
+// 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 routines for in-process value printing in clang-repl.
+//
+//===----------------------------------------------------------------------===//
+
+#include "IncrementalParser.h"
+#include "InterpreterUtils.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/PrettyPrinter.h"
+#include "clang/AST/Type.h"
+#include "clang/Frontend/CompilerInstance.h"
+#include "clang/Interpreter/Interpreter.h"
+#include "clang/Interpreter/Value.h"
+#include "clang/Lex/Preprocessor.h"
+#include "clang/Sema/Lookup.h"
+#include "clang/Sema/Sema.h"
+
+#include "llvm/Support/Error.h"
+#include "llvm/Support/raw_ostream.h"
+
+#include <cassert>
+#include <string>
+
+#include <cstdarg>
+
+namespace clang {
+
+llvm::Expected<llvm::orc::ExecutorAddr>
+Interpreter::CompileDtorCall(CXXRecordDecl *CXXRD) {
+  assert(CXXRD && "Cannot compile a destructor for a nullptr");
+  if (auto Dtor = Dtors.find(CXXRD); Dtor != Dtors.end())
+    return Dtor->getSecond();
+
+  if (CXXRD->hasIrrelevantDestructor())
+    return llvm::orc::ExecutorAddr{};
+
+  CXXDestructorDecl *DtorRD =
+      getCompilerInstance()->getSema().LookupDestructor(CXXRD);
+
+  llvm::StringRef Name =
+      getCodeGen()->GetMangledName(GlobalDecl(DtorRD, Dtor_Base));
+  auto AddrOrErr = getSymbolAddress(Name);
+  if (!AddrOrErr)
+    return AddrOrErr.takeError();
+
+  Dtors[CXXRD] = *AddrOrErr;
+  return AddrOrErr;
+}
+
+enum InterfaceKind { NoAlloc, WithAlloc, CopyArray, NewTag };
+
+class InterfaceKindVisitor
+    : public TypeVisitor<InterfaceKindVisitor, InterfaceKind> {
+
+  Sema &S;
+  Expr *E;
+  llvm::SmallVectorImpl<Expr *> &Args;
+
+public:
+  InterfaceKindVisitor(Sema &S, Expr *E, llvm::SmallVectorImpl<Expr *> &Args)
+      : S(S), E(E), Args(Args) {}
+
+  InterfaceKind computeInterfaceKind(QualType Ty) {
+    return Visit(Ty.getTypePtr());
+  }
+
+  InterfaceKind VisitRecordType(const RecordType *Ty) {
+    return InterfaceKind::WithAlloc;
+  }
+
+  InterfaceKind VisitMemberPointerType(const MemberPointerType *Ty) {
+    return InterfaceKind::WithAlloc;
+  }
+
+  InterfaceKind VisitConstantArrayType(const ConstantArrayType *Ty) {
+    return InterfaceKind::CopyArray;
+  }
+
+  InterfaceKind VisitFunctionProtoType(const FunctionProtoType *Ty) {
+    HandlePtrType(Ty);
+    return InterfaceKind::NoAlloc;
+  }
+
+  InterfaceKind VisitPointerType(const PointerType *Ty) {
+    HandlePtrType(Ty);
+    return InterfaceKind::NoAlloc;
+  }
+
+  InterfaceKind VisitReferenceType(const ReferenceType *Ty) {
+    ExprResult AddrOfE = S.CreateBuiltinUnaryOp(SourceLocation(), UO_AddrOf, E);
+    assert(!AddrOfE.isInvalid() && "Can not create unary expression");
+    Args.push_back(AddrOfE.get());
+    return InterfaceKind::NoAlloc;
+  }
+
+  InterfaceKind VisitBuiltinType(const BuiltinType *Ty) {
+    if (Ty->isNullPtrType())
+      Args.push_back(E);
+    else if (Ty->isFloatingType())
+      Args.push_back(E);
+    else if (Ty->isIntegralOrEnumerationType())
+      HandleIntegralOrEnumType(Ty);
+    else if (Ty->isVoidType()) {
+      // Do we need to still run `E`?
+    }
+
+    return InterfaceKind::NoAlloc;
+  }
+
+  InterfaceKind VisitEnumType(const EnumType *Ty) {
+    HandleIntegralOrEnumType(Ty);
+    return InterfaceKind::NoAlloc;
+  }
+
+private:
+  // Force cast these types to the uint that fits the register size. That way we
+  // reduce the number of overloads of `__clang_Interpreter_SetValueNoAlloc`.
+  void HandleIntegralOrEnumType(const Type *Ty) {
+    ASTContext &Ctx = S.getASTContext();
+    uint64_t PtrBits = Ctx.getTypeSize(Ctx.VoidPtrTy);
+    QualType UIntTy = Ctx.getBitIntType(/*Unsigned=*/true, PtrBits);
+    TypeSourceInfo *TSI = Ctx.getTrivialTypeSourceInfo(UIntTy);
+    ExprResult CastedExpr =
+        S.BuildCStyleCastExpr(SourceLocation(), TSI, SourceLocation(), E);
+    assert(!CastedExpr.isInvalid() && "Cannot create cstyle cast expr");
+    Args.push_back(CastedExpr.get());
+  }
+
+  void HandlePtrType(const Type *Ty) {
+    ASTContext &Ctx = S.getASTContext();
+    TypeSourceInfo *TSI = Ctx.getTrivialTypeSourceInfo(Ctx.VoidPtrTy);
+    ExprResult CastedExpr =
+        S.BuildCStyleCastExpr(SourceLocation(), TSI, SourceLocation(), E);
+    assert(!CastedExpr.isInvalid() && "Can not create cstyle cast expression");
+    Args.push_back(CastedExpr.get());
+  }
+};
+
+// This synthesizes a call expression to a speciall
+// function that is responsible for generating the Value.
+// In general, we transform:
+//   clang-repl> x
+// To:
+//   // 1. If x is a built-in type like int, float.
+//   __clang_Interpreter_SetValueNoAlloc(ThisInterp, OpaqueValue, xQualType, x);
+//   // 2. If x is a struct, and a lvalue.
+//   __clang_Interpreter_SetValueNoAlloc(ThisInterp, OpaqueValue, xQualType,
+//   &x);
+//   // 3. If x is a struct, but a rvalue.
+//   new (__clang_Interpreter_SetValueWithAlloc(ThisInterp, OpaqueValue,
+//   xQualType)) (x);
+llvm::Expected<Expr *> Interpreter::AttachValuePrinting(Expr *E) {
----------------
junaire wrote:

 `AttachValuePrinting` sounds like a bad name IMO, it's not just about printing a value, right? but TBH I can't come up with a better one though....

https://github.com/llvm/llvm-project/pull/107737