[clang][bytecode] Enter a non-constant context when revisiting (#136104)

Otherwise, things like __builtin_is_constant_evaluated() return the
wrong value.

4 files changed, 18 insertions, 1 deletions

diff --git a/clang/lib/AST/ByteCode/Compiler.cpp b/clang/lib/AST/ByteCode/Compiler.cpp
index 157e306..d3eabc5 100644
--- a/clang/lib/AST/ByteCode/Compiler.cpp
+++ b/clang/lib/AST/ByteCode/Compiler.cpp
@@ -6466,8 +6466,13 @@ 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 {
+    if (!this->emitPushCC(VD->hasConstantInitialization(), E))
+      return false;
     auto VarState = this->visitDecl(VD, /*IsConstexprUnknown=*/true);
 
+    if (!this->emitPopCC(E))
+      return false;
+
     if (VarState.notCreated())
       return true;
     if (!VarState)
diff --git a/clang/lib/AST/ByteCode/Interp.h b/clang/lib/AST/ByteCode/Interp.h
index bd58c2a..49e2326 100644
--- a/clang/lib/AST/ByteCode/Interp.h
+++ b/clang/lib/AST/ByteCode/Interp.h
@@ -2848,6 +2848,15 @@ inline bool EndSpeculation(InterpState &S, CodePtr OpPC) {
   return true;
 }
 
+inline bool PushCC(InterpState &S, CodePtr OpPC, bool Value) {
+  S.ConstantContextOverride = Value;
+  return true;
+}
+inline bool PopCC(InterpState &S, CodePtr OpPC) {
+  S.ConstantContextOverride = std::nullopt;
+  return true;
+}
+
 /// Do nothing and just abort execution.
 inline bool Error(InterpState &S, CodePtr OpPC) { return false; }
 
diff --git a/clang/lib/AST/ByteCode/InterpState.h b/clang/lib/AST/ByteCode/InterpState.h
index 74001b8..528c1a2 100644
--- a/clang/lib/AST/ByteCode/InterpState.h
+++ b/clang/lib/AST/ByteCode/InterpState.h
@@ -127,7 +127,6 @@ private:
   SourceMapper *M;
   /// Allocator used for dynamic allocations performed via the program.
   DynamicAllocator Alloc;
-  std::optional<bool> ConstantContextOverride;
 
 public:
   /// Reference to the module containing all bytecode.
@@ -147,6 +146,7 @@ public:
   /// Things needed to do speculative execution.
   SmallVectorImpl<PartialDiagnosticAt> *PrevDiags = nullptr;
   unsigned SpeculationDepth = 0;
+  std::optional<bool> ConstantContextOverride;
 
   llvm::SmallVector<
       std::pair<const Expr *, const LifetimeExtendedTemporaryDecl *>>
diff --git a/clang/lib/AST/ByteCode/Opcodes.td b/clang/lib/AST/ByteCode/Opcodes.td
index 5a9079f..8451e54 100644
--- a/clang/lib/AST/ByteCode/Opcodes.td
+++ b/clang/lib/AST/ByteCode/Opcodes.td
@@ -872,3 +872,6 @@ def GetTypeidPtr : Opcode { let Args = [ArgTypePtr]; }
 def DiagTypeid : Opcode;
 
 def CheckDestruction : Opcode;
+
+def PushCC : Opcode { let Args = [ArgBool]; }
+def PopCC : Opcode;