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Merged
merged 1 commit into from
Jan 19, 2024
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[clang][Interp] Add an EvaluationResult class #71315

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1 change: 1 addition & 0 deletions clang/lib/AST/CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -75,6 +75,7 @@ add_clang_library(clangAST
Interp/Function.cpp
Interp/InterpBuiltin.cpp
Interp/Floating.cpp
Interp/EvaluationResult.cpp
Interp/Interp.cpp
Interp/InterpBlock.cpp
Interp/InterpFrame.cpp
Expand Down
23 changes: 18 additions & 5 deletions clang/lib/AST/ExprConstant.cpp
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Expand Up @@ -15439,11 +15439,13 @@ static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result) {
if (Info.EnableNewConstInterp) {
if (!Info.Ctx.getInterpContext().evaluateAsRValue(Info, E, Result))
return false;
} else {
if (!::Evaluate(Result, Info, E))
return false;
return CheckConstantExpression(Info, E->getExprLoc(), E->getType(), Result,
ConstantExprKind::Normal);
}

if (!::Evaluate(Result, Info, E))
return false;

// Implicit lvalue-to-rvalue cast.
if (E->isGLValue()) {
LValue LV;
Expand Down Expand Up @@ -15671,6 +15673,13 @@ bool Expr::EvaluateAsConstantExpr(EvalResult &Result, const ASTContext &Ctx,
EvalInfo Info(Ctx, Result, EM);
Info.InConstantContext = true;

if (Info.EnableNewConstInterp) {
if (!Info.Ctx.getInterpContext().evaluate(Info, this, Result.Val))
return false;
return CheckConstantExpression(Info, getExprLoc(),
getStorageType(Ctx, this), Result.Val, Kind);
}

// The type of the object we're initializing is 'const T' for a class NTTP.
QualType T = getType();
if (Kind == ConstantExprKind::ClassTemplateArgument)
Expand Down Expand Up @@ -15746,10 +15755,16 @@ bool Expr::EvaluateAsInitializer(APValue &Value, const ASTContext &Ctx,
Info.setEvaluatingDecl(VD, Value);
Info.InConstantContext = IsConstantInitialization;

SourceLocation DeclLoc = VD->getLocation();
QualType DeclTy = VD->getType();

if (Info.EnableNewConstInterp) {
auto &InterpCtx = const_cast<ASTContext &>(Ctx).getInterpContext();
if (!InterpCtx.evaluateAsInitializer(Info, VD, Value))
return false;

return CheckConstantExpression(Info, DeclLoc, DeclTy, Value,
ConstantExprKind::Normal);
} else {
LValue LVal;
LVal.set(VD);
Expand Down Expand Up @@ -15779,8 +15794,6 @@ bool Expr::EvaluateAsInitializer(APValue &Value, const ASTContext &Ctx,
llvm_unreachable("Unhandled cleanup; missing full expression marker?");
}

SourceLocation DeclLoc = VD->getLocation();
QualType DeclTy = VD->getType();
return CheckConstantExpression(Info, DeclLoc, DeclTy, Value,
ConstantExprKind::Normal) &&
CheckMemoryLeaks(Info);
Expand Down
13 changes: 1 addition & 12 deletions clang/lib/AST/Interp/ByteCodeEmitter.cpp
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Expand Up @@ -20,8 +20,7 @@
using namespace clang;
using namespace clang::interp;

Expected<Function *>
ByteCodeEmitter::compileFunc(const FunctionDecl *FuncDecl) {
Function *ByteCodeEmitter::compileFunc(const FunctionDecl *FuncDecl) {
// Set up argument indices.
unsigned ParamOffset = 0;
SmallVector<PrimType, 8> ParamTypes;
Expand Down Expand Up @@ -120,10 +119,6 @@ ByteCodeEmitter::compileFunc(const FunctionDecl *FuncDecl) {

// Compile the function body.
if (!IsEligibleForCompilation || !visitFunc(FuncDecl)) {
// Return a dummy function if compilation failed.
if (BailLocation)
return llvm::make_error<ByteCodeGenError>(*BailLocation);

Func->setIsFullyCompiled(true);
return Func;
}
Expand Down Expand Up @@ -183,12 +178,6 @@ int32_t ByteCodeEmitter::getOffset(LabelTy Label) {
return 0ull;
}

bool ByteCodeEmitter::bail(const SourceLocation &Loc) {
if (!BailLocation)
BailLocation = Loc;
return false;
}

/// Helper to write bytecode and bail out if 32-bit offsets become invalid.
/// Pointers will be automatically marshalled as 32-bit IDs.
template <typename T>
Expand Down
10 changes: 1 addition & 9 deletions clang/lib/AST/Interp/ByteCodeEmitter.h
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Expand Up @@ -17,7 +17,6 @@
#include "PrimType.h"
#include "Program.h"
#include "Source.h"
#include "llvm/Support/Error.h"

namespace clang {
namespace interp {
Expand All @@ -32,7 +31,7 @@ class ByteCodeEmitter {

public:
/// Compiles the function into the module.
llvm::Expected<Function *> compileFunc(const FunctionDecl *FuncDecl);
Function *compileFunc(const FunctionDecl *FuncDecl);

protected:
ByteCodeEmitter(Context &Ctx, Program &P) : Ctx(Ctx), P(P) {}
Expand All @@ -49,11 +48,6 @@ class ByteCodeEmitter {
virtual bool visitExpr(const Expr *E) = 0;
virtual bool visitDecl(const VarDecl *E) = 0;

/// Bails out if a given node cannot be compiled.
bool bail(const Stmt *S) { return bail(S->getBeginLoc()); }
bool bail(const Decl *D) { return bail(D->getBeginLoc()); }
bool bail(const SourceLocation &Loc);

/// Emits jumps.
bool jumpTrue(const LabelTy &Label);
bool jumpFalse(const LabelTy &Label);
Expand Down Expand Up @@ -81,8 +75,6 @@ class ByteCodeEmitter {
LabelTy NextLabel = 0;
/// Offset of the next local variable.
unsigned NextLocalOffset = 0;
/// Location of a failure.
std::optional<SourceLocation> BailLocation;
/// Label information for linker.
llvm::DenseMap<LabelTy, unsigned> LabelOffsets;
/// Location of label relocations.
Expand Down
12 changes: 7 additions & 5 deletions clang/lib/AST/Interp/ByteCodeExprGen.cpp
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Expand Up @@ -371,7 +371,7 @@ bool ByteCodeExprGen<Emitter>::VisitBinaryOperator(const BinaryOperator *BO) {
}

if (!LT || !RT || !T)
return this->bail(BO);
return false;

// Pointer arithmetic special case.
if (BO->getOpcode() == BO_Add || BO->getOpcode() == BO_Sub) {
Expand Down Expand Up @@ -451,7 +451,7 @@ bool ByteCodeExprGen<Emitter>::VisitBinaryOperator(const BinaryOperator *BO) {
case BO_LAnd:
llvm_unreachable("Already handled earlier");
default:
return this->bail(BO);
return false;
}

llvm_unreachable("Unhandled binary op");
Expand Down Expand Up @@ -504,7 +504,7 @@ bool ByteCodeExprGen<Emitter>::VisitPointerArithBinOp(const BinaryOperator *E) {
else if (Op == BO_Sub)
return this->emitSubOffset(OffsetType, E);

return this->bail(E);
return false;
}

template <class Emitter>
Expand Down Expand Up @@ -2358,7 +2358,9 @@ bool ByteCodeExprGen<Emitter>::visitDecl(const VarDecl *VD) {
// Return the value
if (VarT)
return this->emitRet(*VarT, VD);
return this->emitRetValue(VD);

// Return non-primitive values as pointers here.
return this->emitRet(PT_Ptr, VD);
}

template <class Emitter>
Expand All @@ -2378,7 +2380,7 @@ bool ByteCodeExprGen<Emitter>::visitVarDecl(const VarDecl *VD) {
std::optional<unsigned> GlobalIndex = P.createGlobal(VD, Init);

if (!GlobalIndex)
return this->bail(VD);
return false;

assert(Init);
{
Expand Down
4 changes: 0 additions & 4 deletions clang/lib/AST/Interp/ByteCodeExprGen.h
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Expand Up @@ -191,10 +191,6 @@ class ByteCodeExprGen : public ConstStmtVisitor<ByteCodeExprGen<Emitter>, bool>,
if (!visitInitializer(Init))
return false;

if ((Init->getType()->isArrayType() || Init->getType()->isRecordType()) &&
!this->emitCheckGlobalCtor(Init))
return false;

return this->emitPopPtr(Init);
}

Expand Down
2 changes: 1 addition & 1 deletion clang/lib/AST/Interp/ByteCodeStmtGen.cpp
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Expand Up @@ -262,7 +262,7 @@ bool ByteCodeStmtGen<Emitter>::visitStmt(const Stmt *S) {
default: {
if (auto *Exp = dyn_cast<Expr>(S))
return this->discard(Exp);
return this->bail(S);
return false;
}
}
}
Expand Down
106 changes: 73 additions & 33 deletions clang/lib/AST/Interp/Context.cpp
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Expand Up @@ -30,18 +30,8 @@ Context::~Context() {}
bool Context::isPotentialConstantExpr(State &Parent, const FunctionDecl *FD) {
assert(Stk.empty());
Function *Func = P->getFunction(FD);
if (!Func || !Func->hasBody()) {
if (auto R = ByteCodeStmtGen<ByteCodeEmitter>(*this, *P).compileFunc(FD)) {
Func = *R;
} else {
handleAllErrors(R.takeError(), [&Parent](ByteCodeGenError &Err) {
Parent.FFDiag(Err.getRange().getBegin(),
diag::err_experimental_clang_interp_failed)
<< Err.getRange();
});
return false;
}
}
if (!Func || !Func->hasBody())
Func = ByteCodeStmtGen<ByteCodeEmitter>(*this, *P).compileFunc(FD);

APValue DummyResult;
if (!Run(Parent, Func, DummyResult)) {
Expand All @@ -54,36 +44,90 @@ bool Context::isPotentialConstantExpr(State &Parent, const FunctionDecl *FD) {
bool Context::evaluateAsRValue(State &Parent, const Expr *E, APValue &Result) {
assert(Stk.empty());
ByteCodeExprGen<EvalEmitter> C(*this, *P, Parent, Stk, Result);
if (Check(Parent, C.interpretExpr(E))) {
assert(Stk.empty());
#ifndef NDEBUG
// Make sure we don't rely on some value being still alive in
// InterpStack memory.

auto Res = C.interpretExpr(E);

if (Res.isInvalid()) {
Stk.clear();
return false;
}

assert(Stk.empty());
#ifndef NDEBUG
// Make sure we don't rely on some value being still alive in
// InterpStack memory.
Stk.clear();
#endif
return true;

// Implicit lvalue-to-rvalue conversion.
if (E->isGLValue()) {
std::optional<APValue> RValueResult = Res.toRValue();
if (!RValueResult) {
return false;
}
Result = *RValueResult;
} else {
Result = Res.toAPValue();
}

return true;
}

bool Context::evaluate(State &Parent, const Expr *E, APValue &Result) {
assert(Stk.empty());
ByteCodeExprGen<EvalEmitter> C(*this, *P, Parent, Stk, Result);

auto Res = C.interpretExpr(E);
if (Res.isInvalid()) {
Stk.clear();
return false;
}

assert(Stk.empty());
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Should we be asserting that we have an rvalue as opposed to an lvalue?

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We could have either here and just return what we have.

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Ah, okay!

#ifndef NDEBUG
// Make sure we don't rely on some value being still alive in
// InterpStack memory.
Stk.clear();
return false;
#endif
Result = Res.toAPValue();
return true;
}

bool Context::evaluateAsInitializer(State &Parent, const VarDecl *VD,
APValue &Result) {
assert(Stk.empty());
ByteCodeExprGen<EvalEmitter> C(*this, *P, Parent, Stk, Result);
if (Check(Parent, C.interpretDecl(VD))) {
assert(Stk.empty());
#ifndef NDEBUG
// Make sure we don't rely on some value being still alive in
// InterpStack memory.

auto Res = C.interpretDecl(VD);
if (Res.isInvalid()) {
Stk.clear();
#endif
return true;
return false;
}

assert(Stk.empty());
#ifndef NDEBUG
// Make sure we don't rely on some value being still alive in
// InterpStack memory.
Stk.clear();
return false;
#endif

// Ensure global variables are fully initialized.
if (shouldBeGloballyIndexed(VD) && !Res.isInvalid() &&
(VD->getType()->isRecordType() || VD->getType()->isArrayType())) {
assert(Res.isLValue());

if (!Res.checkFullyInitialized(C.getState()))
return false;

// lvalue-to-rvalue conversion.
std::optional<APValue> RValueResult = Res.toRValue();
if (!RValueResult)
return false;
Result = *RValueResult;
Comment on lines +122 to +126
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We should probably turn this into a function rather than reimplement it in different places.

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The two versions are slightly different: in evaluateInitializer(), we always do the conversion for global variables, but in the version in evaluateAsRValue only for GLValues. I could make the EvaluationResult API a littler easier to use for the cases in Context though, i.e. bool toRValue(APValue &Result) instead of returning the std::optional.

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Okay, that seems fine to do in a follow-up.


} else
Result = Res.toAPValue();
return true;
}

const LangOptions &Context::getLangOpts() const { return Ctx.getLangOpts(); }
Expand Down Expand Up @@ -234,12 +278,8 @@ const Function *Context::getOrCreateFunction(const FunctionDecl *FD) {
return Func;

if (!Func || WasNotDefined) {
if (auto R = ByteCodeStmtGen<ByteCodeEmitter>(*this, *P).compileFunc(FD))
Func = *R;
else {
llvm::consumeError(R.takeError());
return nullptr;
}
if (auto F = ByteCodeStmtGen<ByteCodeEmitter>(*this, *P).compileFunc(FD))
Func = F;
}

return Func;
Expand Down
3 changes: 3 additions & 0 deletions clang/lib/AST/Interp/Context.h
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Expand Up @@ -51,6 +51,9 @@ class Context final {
/// Evaluates a toplevel expression as an rvalue.
bool evaluateAsRValue(State &Parent, const Expr *E, APValue &Result);

/// Like evaluateAsRvalue(), but does no implicit lvalue-to-rvalue conversion.
bool evaluate(State &Parent, const Expr *E, APValue &Result);

/// Evaluates a toplevel initializer.
bool evaluateAsInitializer(State &Parent, const VarDecl *VD, APValue &Result);

Expand Down
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