tbaeder created this revision.
tbaeder added reviewers: aaron.ballman, erichkeane, tahonermann, shafik.
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tbaeder requested review of this revision.
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Another try at this.
This time, only implement `__builtin_is_constant_evaluated()`.
Unfortunately I can't just use
`clang/test/SemaCXX/builtin-is-constant-evaluated.cpp` because there are some
other unsupported expressions in there.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D137487
Files:
clang/lib/AST/CMakeLists.txt
clang/lib/AST/Interp/ByteCodeExprGen.cpp
clang/lib/AST/Interp/Function.h
clang/lib/AST/Interp/Interp.cpp
clang/lib/AST/Interp/Interp.h
clang/lib/AST/Interp/InterpBuiltin.cpp
clang/test/AST/Interp/builtins.cpp
Index: clang/test/AST/Interp/builtins.cpp
===================================================================
--- /dev/null
+++ clang/test/AST/Interp/builtins.cpp
@@ -0,0 +1,25 @@
+// RUN: %clang_cc1 -fexperimental-new-constant-interpreter %s -verify
+// RUN: %clang_cc1 -fexperimental-new-constant-interpreter %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -verify=ref %s -Wno-constant-evaluated
+// RUN: %clang_cc1 -verify=ref %s -Wno-constant-evaluated
+// RUN: %clang_cc1 -verify=ref %s -Wno-constant-evaluated -S -emit-llvm -o - | FileCheck %s
+
+// expected-no-diagnostics
+// ref-no-diagnostics
+
+using size_t = decltype(sizeof(int));
+
+namespace std {
+inline constexpr bool is_constant_evaluated() noexcept {
+ return __builtin_is_constant_evaluated();
+}
+} // namespace std
+
+constexpr bool b = std::is_constant_evaluated();
+static_assert(b, "");
+static_assert(std::is_constant_evaluated() , "");
+
+
+bool is_this_constant() {
+ return __builtin_is_constant_evaluated(); // CHECK: ret i1 false
+}
Index: clang/lib/AST/Interp/InterpBuiltin.cpp
===================================================================
--- /dev/null
+++ clang/lib/AST/Interp/InterpBuiltin.cpp
@@ -0,0 +1,51 @@
+//===--- InterpBuiltin.cpp - Interpreter for the constexpr VM ---*- 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
+//
+//===----------------------------------------------------------------------===//
+#include "Boolean.h"
+#include "Interp.h"
+#include "PrimType.h"
+#include "clang/Basic/Builtins.h"
+
+namespace clang {
+namespace interp {
+
+/// This is a slightly simplified version of the Ret() we have in Interp.cpp
+/// If they end up diverging in the future, we should get rid of the code
+/// duplication.
+template <PrimType Name, class T = typename PrimConv<Name>::T>
+static bool Ret(InterpState &S, CodePtr &PC) {
+ S.CallStackDepth--;
+ const T &Ret = S.Stk.pop<T>();
+
+ assert(S.Current->getFrameOffset() == S.Stk.size() && "Invalid frame");
+ if (!S.checkingPotentialConstantExpression())
+ S.Current->popArgs();
+
+ InterpFrame *Caller = S.Current->Caller;
+ assert(Caller);
+
+ PC = S.Current->getRetPC();
+ delete S.Current;
+ S.Current = Caller;
+ S.Stk.push<T>(Ret);
+
+ return true;
+}
+
+bool InterpretBuiltin(InterpState &S, CodePtr PC, unsigned BuiltinID) {
+ switch (BuiltinID) {
+ case Builtin::BI__builtin_is_constant_evaluated:
+ S.Stk.push<Boolean>(Boolean::from(S.inConstantContext()));
+ Ret<PT_Bool>(S, PC);
+ return true;
+ }
+
+ return false;
+}
+
+} // namespace interp
+} // namespace clang
Index: clang/lib/AST/Interp/Interp.h
===================================================================
--- clang/lib/AST/Interp/Interp.h
+++ clang/lib/AST/Interp/Interp.h
@@ -110,6 +110,8 @@
/// Interpreter entry point.
bool Interpret(InterpState &S, APValue &Result);
+bool InterpretBuiltin(InterpState &S, CodePtr PC, unsigned BuiltinID);
+
enum class ArithOp { Add, Sub };
//===----------------------------------------------------------------------===//
@@ -1349,21 +1351,29 @@
InterpFrame *FrameBefore = S.Current;
S.Current = NewFrame.get();
- APValue CallResult;
- // Note that we cannot assert(CallResult.hasValue()) here since
- // Ret() above only sets the APValue if the curent frame doesn't
- // have a caller set.
- if (Interpret(S, CallResult)) {
- NewFrame.release(); // Frame was delete'd already.
- assert(S.Current == FrameBefore);
-
- // For constructors, check that all fields have been initialized.
- if (Func->isConstructor()) {
- if (!CheckCtorCall(S, PC, ThisPtr))
- return false;
+ // Evaluate builtin functions directly.
+ if (unsigned BID = Func->getBuiltinID()) {
+ if (InterpretBuiltin(S, PC, BID)) {
+ NewFrame.release();
+ return true;
}
+ } else {
+ APValue CallResult;
+ // Note that we cannot assert(CallResult.hasValue()) here since
+ // Ret() above only sets the APValue if the curent frame doesn't
+ // have a caller set.
+ if (Interpret(S, CallResult)) {
+ NewFrame.release(); // Frame was delete'd already.
+ assert(S.Current == FrameBefore);
+
+ // For constructors, check that all fields have been initialized.
+ if (Func->isConstructor()) {
+ if (!CheckCtorCall(S, PC, ThisPtr))
+ return false;
+ }
- return true;
+ return true;
+ }
}
// Interpreting the function failed somehow. Reset to
Index: clang/lib/AST/Interp/Interp.cpp
===================================================================
--- clang/lib/AST/Interp/Interp.cpp
+++ clang/lib/AST/Interp/Interp.cpp
@@ -349,6 +349,11 @@
}
}
+ // Builtin functions are always fine, provided we implement them, which
+ // we will check later.
+ if (F->getBuiltinID())
+ return true;
+
if (!F->isConstexpr()) {
const SourceLocation &Loc = S.Current->getLocation(OpPC);
if (S.getLangOpts().CPlusPlus11) {
Index: clang/lib/AST/Interp/Function.h
===================================================================
--- clang/lib/AST/Interp/Function.h
+++ clang/lib/AST/Interp/Function.h
@@ -138,6 +138,8 @@
// Checks if the funtion already has a body attached.
bool hasBody() const { return HasBody; }
+ unsigned getBuiltinID() const { return F->getBuiltinID(); }
+
unsigned getNumParams() const { return ParamTypes.size(); }
private:
Index: clang/lib/AST/Interp/ByteCodeExprGen.cpp
===================================================================
--- clang/lib/AST/Interp/ByteCodeExprGen.cpp
+++ clang/lib/AST/Interp/ByteCodeExprGen.cpp
@@ -1370,10 +1370,8 @@
template <class Emitter>
bool ByteCodeExprGen<Emitter>::VisitCallExpr(const CallExpr *E) {
- assert(!E->getBuiltinCallee() && "Builtin functions aren't supported yet");
-
const Decl *Callee = E->getCalleeDecl();
- if (const auto *FuncDecl = dyn_cast_or_null<FunctionDecl>(Callee)) {
+ if (const auto *FuncDecl = dyn_cast_if_present<FunctionDecl>(Callee)) {
const Function *Func = getFunction(FuncDecl);
if (!Func)
return false;
Index: clang/lib/AST/CMakeLists.txt
===================================================================
--- clang/lib/AST/CMakeLists.txt
+++ clang/lib/AST/CMakeLists.txt
@@ -73,6 +73,7 @@
Interp/Frame.cpp
Interp/Function.cpp
Interp/Floating.cpp
+ Interp/InterpBuiltin.cpp
Interp/Interp.cpp
Interp/InterpBlock.cpp
Interp/InterpFrame.cpp
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