tbaeder created this revision.
tbaeder added reviewers: aaron.ballman, tahonermann, erichkeane, shafik.
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tbaeder requested review of this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.
There was already //some// form of this, but it wasn't working. I moved the
depth tracking from `InterpState` to `InterpFrame` so remove some of the magic
from the `Ret` instructions.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D148614
Files:
clang/lib/AST/Interp/Interp.cpp
clang/lib/AST/Interp/Interp.h
clang/lib/AST/Interp/InterpFrame.cpp
clang/lib/AST/Interp/InterpFrame.h
clang/lib/AST/Interp/InterpState.cpp
clang/lib/AST/Interp/InterpState.h
clang/test/AST/Interp/depth-limit.cpp
Index: clang/test/AST/Interp/depth-limit.cpp
===================================================================
--- /dev/null
+++ clang/test/AST/Interp/depth-limit.cpp
@@ -0,0 +1,35 @@
+// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -fconstexpr-depth 100 -verify %s
+// RUN: %clang_cc1 -fconstexpr-depth 100 -verify=ref %s
+
+
+/// Note that the diagnostics are slightly different.
+
+constexpr int f(int a) {
+ return f(a + 1); // ref-note {{exceeded maximum depth of 100 calls}} \
+ // ref-note {{in call to 'f(99)'}} \
+ // ref-note {{in call to 'f(98)'}} \
+ // ref-note {{in call to 'f(97)'}} \
+ // ref-note {{in call to 'f(96)'}} \
+ // ref-note {{in call to 'f(95)'}} \
+ // ref-note {{skipping 90 calls in backtrace}} \
+ // ref-note {{in call to 'f(4)'}} \
+ // ref-note {{in call to 'f(3)'}} \
+ // ref-note {{in call to 'f(2)'}} \
+ // ref-note {{in call to 'f(1)'}} \
+ // expected-note {{exceeded maximum depth of 100 calls}} \
+ // expected-note {{in call to 'f(100)'}} \
+ // expected-note {{in call to 'f(99)'}} \
+ // expected-note {{in call to 'f(98)'}} \
+ // expected-note {{in call to 'f(97)'}} \
+ // expected-note {{in call to 'f(96)'}} \
+ // expected-note {{skipping 90 calls in backtrace}} \
+ // expected-note {{in call to 'f(5)'}} \
+ // expected-note {{in call to 'f(4)'}} \
+ // expected-note {{in call to 'f(3)'}} \
+ // expected-note {{in call to 'f(2)'}} \
+ // expected-note {{in call to 'f(1)'}}
+}
+static_assert(f(0) == 100); // ref-error {{not an integral constant expression}} \
+ // ref-note {{in call to 'f(0)'}} \
+ // expected-error {{not an integral constant expression}} \
+ // expected-note {{in call to 'f(0)'}}
Index: clang/lib/AST/Interp/InterpState.h
===================================================================
--- clang/lib/AST/Interp/InterpState.h
+++ clang/lib/AST/Interp/InterpState.h
@@ -15,6 +15,7 @@
#include "Context.h"
#include "Function.h"
+#include "InterpFrame.h"
#include "InterpStack.h"
#include "State.h"
#include "clang/AST/APValue.h"
@@ -41,7 +42,9 @@
// Stack frame accessors.
Frame *getSplitFrame() { return Parent.getCurrentFrame(); }
Frame *getCurrentFrame() override;
- unsigned getCallStackDepth() override { return CallStackDepth; }
+ unsigned getCallStackDepth() override {
+ return Current ? Current->getDepth() : 1;
+ }
const Frame *getBottomFrame() const override {
return Parent.getBottomFrame();
}
@@ -103,8 +106,6 @@
Context &Ctx;
/// The current frame.
InterpFrame *Current = nullptr;
- /// Call stack depth.
- unsigned CallStackDepth;
};
} // namespace interp
Index: clang/lib/AST/Interp/InterpState.cpp
===================================================================
--- clang/lib/AST/Interp/InterpState.cpp
+++ clang/lib/AST/Interp/InterpState.cpp
@@ -17,8 +17,7 @@
InterpState::InterpState(State &Parent, Program &P, InterpStack &Stk,
Context &Ctx, SourceMapper *M)
- : Parent(Parent), M(M), P(P), Stk(Stk), Ctx(Ctx), Current(nullptr),
- CallStackDepth(Parent.getCallStackDepth() + 1) {}
+ : Parent(Parent), M(M), P(P), Stk(Stk), Ctx(Ctx), Current(nullptr) {}
InterpState::~InterpState() {
while (Current) {
Index: clang/lib/AST/Interp/InterpFrame.h
===================================================================
--- clang/lib/AST/Interp/InterpFrame.h
+++ clang/lib/AST/Interp/InterpFrame.h
@@ -15,7 +15,6 @@
#include "Frame.h"
#include "Program.h"
-#include "State.h"
#include <cstdint>
#include <vector>
@@ -120,6 +119,8 @@
const Expr *getExpr(CodePtr PC) const;
SourceLocation getLocation(CodePtr PC) const;
+ unsigned getDepth() const { return Depth; }
+
private:
/// Returns an original argument from the stack.
template <typename T> const T &stackRef(unsigned Offset) const {
@@ -145,6 +146,8 @@
private:
/// Reference to the interpreter state.
InterpState &S;
+ /// Depth of this frame.
+ unsigned Depth;
/// Reference to the function being executed.
const Function *Func;
/// Current object pointer for methods.
Index: clang/lib/AST/Interp/InterpFrame.cpp
===================================================================
--- clang/lib/AST/Interp/InterpFrame.cpp
+++ clang/lib/AST/Interp/InterpFrame.cpp
@@ -23,8 +23,8 @@
InterpFrame::InterpFrame(InterpState &S, const Function *Func,
InterpFrame *Caller, CodePtr RetPC)
- : Caller(Caller), S(S), Func(Func), RetPC(RetPC),
- ArgSize(Func ? Func->getArgSize() : 0),
+ : Caller(Caller), S(S), Depth(Caller ? Caller->Depth + 1 : 0), Func(Func),
+ RetPC(RetPC), ArgSize(Func ? Func->getArgSize() : 0),
Args(static_cast<char *>(S.Stk.top())), FrameOffset(S.Stk.size()) {
if (!Func)
return;
Index: clang/lib/AST/Interp/Interp.h
===================================================================
--- clang/lib/AST/Interp/Interp.h
+++ clang/lib/AST/Interp/Interp.h
@@ -158,7 +158,6 @@
template <PrimType Name, bool Builtin = false,
class T = typename PrimConv<Name>::T>
bool Ret(InterpState &S, CodePtr &PC, APValue &Result) {
- S.CallStackDepth--;
const T &Ret = S.Stk.pop<T>();
assert(S.Current->getFrameOffset() == S.Stk.size() && "Invalid frame");
@@ -181,8 +180,6 @@
template <bool Builtin = false>
inline bool RetVoid(InterpState &S, CodePtr &PC, APValue &Result) {
- S.CallStackDepth--;
-
assert(S.Current->getFrameOffset() == S.Stk.size() && "Invalid frame");
if (Builtin || !S.checkingPotentialConstantExpression())
S.Current->popArgs();
Index: clang/lib/AST/Interp/Interp.cpp
===================================================================
--- clang/lib/AST/Interp/Interp.cpp
+++ clang/lib/AST/Interp/Interp.cpp
@@ -338,6 +338,14 @@
return false;
}
+ // Check if calling the function would exceed our call depth limit.
+ if (S.Current->getDepth() > S.getLangOpts().ConstexprCallDepth) {
+ S.FFDiag(S.Current->getSource(OpPC),
+ diag::note_constexpr_depth_limit_exceeded)
+ << S.getLangOpts().ConstexprCallDepth;
+ return false;
+ }
+
return true;
}
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