[clang][bytecode] Explicitly mark constexpr-unknown variables as such #135806
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
llvmbot
added
clang
Member
|
@llvm/pr-subscribers-clang Author: Timm Baeder (tbaederr) ChangesInstead of trying to figure out what's constexpr-unknown later on. Full diff: https://github.com/llvm/llvm-project/pull/135806.diff 7 Files Affected:
diff --git a/clang/lib/AST/ByteCode/Compiler.cpp b/clang/lib/AST/ByteCode/Compiler.cpp
index 2e22c85ed5f6d..afd8d09a088cd 100644
--- a/clang/lib/AST/ByteCode/Compiler.cpp
+++ b/clang/lib/AST/ByteCode/Compiler.cpp
@@ -4293,7 +4293,8 @@ bool Compiler<Emitter>::emitConst(const APSInt &Value, const Expr *E) {
template <class Emitter>
unsigned Compiler<Emitter>::allocateLocalPrimitive(
- DeclTy &&Src, PrimType Ty, bool IsConst, const ValueDecl *ExtendingDecl) {
+ DeclTy &&Src, PrimType Ty, bool IsConst, const ValueDecl *ExtendingDecl,
+ bool IsConstexprUnknown) {
// Make sure we don't accidentally register the same decl twice.
if (const auto *VD =
dyn_cast_if_present<ValueDecl>(Src.dyn_cast<const Decl *>())) {
@@ -4307,6 +4308,7 @@ unsigned Compiler<Emitter>::allocateLocalPrimitive(
// or isa<MaterializeTemporaryExpr>().
Descriptor *D = P.createDescriptor(Src, Ty, nullptr, Descriptor::InlineDescMD,
IsConst, isa<const Expr *>(Src));
+ D->IsConstexprUnknown = IsConstexprUnknown;
Scope::Local Local = this->createLocal(D);
if (auto *VD = dyn_cast_if_present<ValueDecl>(Src.dyn_cast<const Decl *>()))
Locals.insert({VD, Local});
@@ -4320,7 +4322,8 @@ unsigned Compiler<Emitter>::allocateLocalPrimitive(
template <class Emitter>
std::optional<unsigned>
Compiler<Emitter>::allocateLocal(DeclTy &&Src, QualType Ty,
- const ValueDecl *ExtendingDecl) {
+ const ValueDecl *ExtendingDecl,
+ bool IsConstexprUnknown) {
// Make sure we don't accidentally register the same decl twice.
if ([[maybe_unused]] const auto *VD =
dyn_cast_if_present<ValueDecl>(Src.dyn_cast<const Decl *>())) {
@@ -4349,6 +4352,7 @@ Compiler<Emitter>::allocateLocal(DeclTy &&Src, QualType Ty,
IsTemporary, /*IsMutable=*/false, Init);
if (!D)
return std::nullopt;
+ D->IsConstexprUnknown = IsConstexprUnknown;
Scope::Local Local = this->createLocal(D);
if (Key)
@@ -4460,9 +4464,10 @@ bool Compiler<Emitter>::visitExpr(const Expr *E, bool DestroyToplevelScope) {
}
template <class Emitter>
-VarCreationState Compiler<Emitter>::visitDecl(const VarDecl *VD) {
+VarCreationState Compiler<Emitter>::visitDecl(const VarDecl *VD,
+ bool IsConstexprUnknown) {
- auto R = this->visitVarDecl(VD, /*Toplevel=*/true);
+ auto R = this->visitVarDecl(VD, /*Toplevel=*/true, IsConstexprUnknown);
if (R.notCreated())
return R;
@@ -4550,7 +4555,8 @@ bool Compiler<Emitter>::visitDeclAndReturn(const VarDecl *VD,
template <class Emitter>
VarCreationState Compiler<Emitter>::visitVarDecl(const VarDecl *VD,
- bool Toplevel) {
+ bool Toplevel,
+ bool IsConstexprUnknown) {
// We don't know what to do with these, so just return false.
if (VD->getType().isNull())
return false;
@@ -4620,7 +4626,8 @@ VarCreationState Compiler<Emitter>::visitVarDecl(const VarDecl *VD,
if (VarT) {
unsigned Offset = this->allocateLocalPrimitive(
- VD, *VarT, VD->getType().isConstQualified());
+ VD, *VarT, VD->getType().isConstQualified(), nullptr,
+ IsConstexprUnknown);
if (Init) {
// If this is a toplevel declaration, create a scope for the
// initializer.
@@ -4636,7 +4643,8 @@ VarCreationState Compiler<Emitter>::visitVarDecl(const VarDecl *VD,
}
}
} else {
- if (std::optional<unsigned> Offset = this->allocateLocal(VD)) {
+ if (std::optional<unsigned> Offset = this->allocateLocal(
+ VD, VD->getType(), nullptr, IsConstexprUnknown)) {
if (!Init)
return true;
@@ -6461,7 +6469,7 @@ bool Compiler<Emitter>::visitDeclRef(const ValueDecl *D, const Expr *E) {
// In case we need to re-visit a declaration.
auto revisit = [&](const VarDecl *VD) -> bool {
- auto VarState = this->visitDecl(VD);
+ auto VarState = this->visitDecl(VD, /*IsConstexprUnknown=*/true);
if (VarState.notCreated())
return true;
diff --git a/clang/lib/AST/ByteCode/Compiler.h b/clang/lib/AST/ByteCode/Compiler.h
index 858957367d85d..a3090a8a31189 100644
--- a/clang/lib/AST/ByteCode/Compiler.h
+++ b/clang/lib/AST/ByteCode/Compiler.h
@@ -286,8 +286,10 @@ class Compiler : public ConstStmtVisitor<Compiler<Emitter>, bool>,
/// intact.
bool delegate(const Expr *E);
/// Creates and initializes a variable from the given decl.
- VarCreationState visitVarDecl(const VarDecl *VD, bool Toplevel = false);
- VarCreationState visitDecl(const VarDecl *VD);
+ VarCreationState visitVarDecl(const VarDecl *VD, bool Toplevel = false,
+ bool IsConstexprUnknown = false);
+ VarCreationState visitDecl(const VarDecl *VD,
+ bool IsConstexprUnknown = false);
/// Visit an APValue.
bool visitAPValue(const APValue &Val, PrimType ValType, const Expr *E);
bool visitAPValueInitializer(const APValue &Val, const Expr *E, QualType T);
@@ -303,12 +305,14 @@ class Compiler : public ConstStmtVisitor<Compiler<Emitter>, bool>,
/// Creates a local primitive value.
unsigned allocateLocalPrimitive(DeclTy &&Decl, PrimType Ty, bool IsConst,
- const ValueDecl *ExtendingDecl = nullptr);
+ const ValueDecl *ExtendingDecl = nullptr,
+ bool IsConstexprUnknown = false);
/// Allocates a space storing a local given its type.
std::optional<unsigned>
allocateLocal(DeclTy &&Decl, QualType Ty = QualType(),
- const ValueDecl *ExtendingDecl = nullptr);
+ const ValueDecl *ExtendingDecl = nullptr,
+ bool IsConstexprUnknown = false);
std::optional<unsigned> allocateTemporary(const Expr *E);
private:
diff --git a/clang/lib/AST/ByteCode/Descriptor.h b/clang/lib/AST/ByteCode/Descriptor.h
index 9acabfd31d80b..a0705cc8c377f 100644
--- a/clang/lib/AST/ByteCode/Descriptor.h
+++ b/clang/lib/AST/ByteCode/Descriptor.h
@@ -168,6 +168,7 @@ struct Descriptor final {
const bool IsArray = false;
/// Flag indicating if this is a dummy descriptor.
bool IsDummy = false;
+ bool IsConstexprUnknown = false;
/// Storage management methods.
const BlockCtorFn CtorFn = nullptr;
diff --git a/clang/lib/AST/ByteCode/Disasm.cpp b/clang/lib/AST/ByteCode/Disasm.cpp
index d4c9ce6050b85..4bdf0f0afb1b0 100644
--- a/clang/lib/AST/ByteCode/Disasm.cpp
+++ b/clang/lib/AST/ByteCode/Disasm.cpp
@@ -376,6 +376,8 @@ LLVM_DUMP_METHOD void Descriptor::dump(llvm::raw_ostream &OS) const {
if (isDummy())
OS << " dummy";
+ if (IsConstexprUnknown)
+ OS << " constexpr-unknown";
}
/// Dump descriptor, including all valid offsets.
diff --git a/clang/lib/AST/ByteCode/Interp.cpp b/clang/lib/AST/ByteCode/Interp.cpp
index 3e1f36da8925f..4625154ac353d 100644
--- a/clang/lib/AST/ByteCode/Interp.cpp
+++ b/clang/lib/AST/ByteCode/Interp.cpp
@@ -299,15 +299,14 @@ void cleanupAfterFunctionCall(InterpState &S, CodePtr OpPC,
TYPE_SWITCH(Ty, S.Stk.discard<T>());
}
-// FIXME: Instead of using this fairly expensive test, we should
-// just mark constexpr-unknown values when creating them.
bool isConstexprUnknown(const Pointer &P) {
if (!P.isBlockPointer())
return false;
+
if (P.isDummy())
- return false;
- const VarDecl *VD = P.block()->getDescriptor()->asVarDecl();
- return VD && VD->hasLocalStorage() && !isa<ParmVarDecl>(VD);
+ return isa_and_nonnull<ParmVarDecl>(P.getDeclDesc()->asValueDecl());
+
+ return P.getDeclDesc()->IsConstexprUnknown;
}
bool CheckBCPResult(InterpState &S, const Pointer &Ptr) {
diff --git a/clang/lib/AST/ByteCode/Program.cpp b/clang/lib/AST/ByteCode/Program.cpp
index c83f5579fd55f..fdb7b960ff06d 100644
--- a/clang/lib/AST/ByteCode/Program.cpp
+++ b/clang/lib/AST/ByteCode/Program.cpp
@@ -156,7 +156,7 @@ unsigned Program::getOrCreateDummy(const DeclTy &D) {
if (const auto *E = dyn_cast<const Expr *>(D)) {
QT = E->getType();
} else {
- const ValueDecl *VD = cast<ValueDecl>(cast<const Decl *>(D));
+ const auto *VD = cast<ValueDecl>(cast<const Decl *>(D));
IsWeak = VD->isWeak();
QT = VD->getType();
if (const auto *RT = QT->getAs<ReferenceType>())
diff --git a/clang/test/AST/ByteCode/codegen.cpp b/clang/test/AST/ByteCode/codegen.cpp
index 7c853a20362b8..6f9e75eac6026 100644
--- a/clang/test/AST/ByteCode/codegen.cpp
+++ b/clang/test/AST/ByteCode/codegen.cpp
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 -triple x86_64-linux -emit-llvm -o - %s | FileCheck %s
-// RUN: %clang_cc1 -triple x86_64-linux -emit-llvm -o - %s -fexperimental-new-constant-interpreter | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-linux -emit-llvm -o - %s -fcxx-exceptions | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-linux -emit-llvm -o - %s -fcxx-exceptions -fexperimental-new-constant-interpreter | FileCheck %s
#ifdef __SIZEOF_INT128__
// CHECK: @PR11705 = global i128 0
@@ -104,3 +104,34 @@ int notdead() {
}
// CHECK: _ZZ7notdeadvEN3$_0clEv
// CHECK: ret i32 %cond
+
+/// The conmparison of those two parameters should NOT work.
+bool paramcmp(const int& lhs, const int& rhs) {
+ if (&lhs == &rhs)
+ return true;
+ return false;
+}
+// CHECK: _Z8paramcmpRKiS0_
+// CHECK: if.then
+// CHECK: if.end
+
+/// &x == &OuterX should work and return 0.
+class X {
+public:
+ X();
+ X(const X&);
+ X(const volatile X &);
+ ~X();
+};
+
+extern X OuterX;
+
+X test24() {
+ X x;
+ if (&x == &OuterX)
+ throw 0;
+ return x;
+}
+// CHECK: _Z6test24v
+// CHECK-NOT: eh.resume
+// CHECK-NOT: unreachable
|
Instead of trying to figure out what's constexpr-unknown later on.
tbaederr
force-pushed
the
constexpr-unknown
branch
from
17b01c6 to
038f7cb
Compare
cor3ntin
approved these changes
Apr 16, 2025
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Instead of trying to figure out what's constexpr-unknown later on.