Reapply "Reapply "[clang][bytecode] Allocate IntegralAP and Floating … (#145014)

…types usi… (#144676)"

This reverts commit 68471d29eed2c49f9b439e505b3f24d387d54f97.

IntegralAP contains a union:
  union {
    uint64_t *Memory = nullptr;
    uint64_t Val;
  };

On 64bit systems, both Memory and Val have the same size. However, on 32
bit system, Val is 64bit and Memory only 32bit. Which means the default
initializer for Memory will only zero half of Val. We fixed this by
zero-initializing Val explicitly in the IntegralAP(unsigned BitWidth)
constructor.


See also the discussion in
https://github.com/llvm/llvm-project/pull/144246

1 files changed, 63 insertions, 50 deletions

diff --git a/clang/lib/AST/ByteCode/Compiler.cpp b/clang/lib/AST/ByteCode/Compiler.cpp
index 9fe4803..c5ac402 100644
--- a/clang/lib/AST/ByteCode/Compiler.cpp
+++ b/clang/lib/AST/ByteCode/Compiler.cpp
@@ -748,7 +748,8 @@ bool Compiler<Emitter>::VisitFloatingLiteral(const FloatingLiteral *E) {
   if (DiscardResult)
     return true;
 
-  return this->emitConstFloat(E->getValue(), E);
+  APFloat F = E->getValue();
+  return this->emitFloat(F, E);
 }
 
 template <class Emitter>
@@ -4185,13 +4186,14 @@ bool Compiler<Emitter>::visitZeroInitializer(PrimType T, QualType QT,
                              nullptr, E);
   case PT_MemberPtr:
     return this->emitNullMemberPtr(0, nullptr, E);
-  case PT_Float:
-    return this->emitConstFloat(APFloat::getZero(Ctx.getFloatSemantics(QT)), E);
+  case PT_Float: {
+    APFloat F = APFloat::getZero(Ctx.getFloatSemantics(QT));
+    return this->emitFloat(F, E);
+  }
   case PT_FixedPoint: {
     auto Sem = Ctx.getASTContext().getFixedPointSemantics(E->getType());
     return this->emitConstFixedPoint(FixedPoint::zero(Sem), E);
   }
-    llvm_unreachable("Implement");
   }
   llvm_unreachable("unknown primitive type");
 }
@@ -4674,10 +4676,7 @@ VarCreationState Compiler<Emitter>::visitVarDecl(const VarDecl *VD,
       if (!visitInitializer(Init))
         return false;
 
-      if (!this->emitFinishInit(Init))
-        return false;
-
-      return this->emitPopPtr(Init);
+      return this->emitFinishInitGlobal(Init);
     };
 
     DeclScope<Emitter> LocalScope(this, VD);
@@ -4698,51 +4697,45 @@ VarCreationState Compiler<Emitter>::visitVarDecl(const VarDecl *VD,
       return false;
 
     return !Init || (checkDecl() && initGlobal(*GlobalIndex));
-  } else {
-    InitLinkScope<Emitter> ILS(this, InitLink::Decl(VD));
-
-    if (VarT) {
-      unsigned Offset = this->allocateLocalPrimitive(
-          VD, *VarT, VD->getType().isConstQualified(), nullptr,
-          ScopeKind::Block, IsConstexprUnknown);
-      if (Init) {
-        // If this is a toplevel declaration, create a scope for the
-        // initializer.
-        if (Toplevel) {
-          LocalScope<Emitter> Scope(this);
-          if (!this->visit(Init))
-            return false;
-          return this->emitSetLocal(*VarT, Offset, VD) && Scope.destroyLocals();
-        } else {
-          if (!this->visit(Init))
-            return false;
-          return this->emitSetLocal(*VarT, Offset, VD);
-        }
-      }
-    } else {
-      if (std::optional<unsigned> Offset =
-              this->allocateLocal(VD, VD->getType(), nullptr, ScopeKind::Block,
-                                  IsConstexprUnknown)) {
-        if (!Init)
-          return true;
+  }
+  // Local variables.
+  InitLinkScope<Emitter> ILS(this, InitLink::Decl(VD));
 
-        if (!this->emitGetPtrLocal(*Offset, Init))
+  if (VarT) {
+    unsigned Offset = this->allocateLocalPrimitive(
+        VD, *VarT, VD->getType().isConstQualified(), nullptr, ScopeKind::Block,
+        IsConstexprUnknown);
+    if (Init) {
+      // If this is a toplevel declaration, create a scope for the
+      // initializer.
+      if (Toplevel) {
+        LocalScope<Emitter> Scope(this);
+        if (!this->visit(Init))
           return false;
-
-        if (!visitInitializer(Init))
+        return this->emitSetLocal(*VarT, Offset, VD) && Scope.destroyLocals();
+      } else {
+        if (!this->visit(Init))
           return false;
+        return this->emitSetLocal(*VarT, Offset, VD);
+      }
+    }
+  } else {
+    if (std::optional<unsigned> Offset = this->allocateLocal(
+            VD, VD->getType(), nullptr, ScopeKind::Block, IsConstexprUnknown)) {
+      if (!Init)
+        return true;
 
-        if (!this->emitFinishInit(Init))
-          return false;
+      if (!this->emitGetPtrLocal(*Offset, Init))
+        return false;
 
-        return this->emitPopPtr(Init);
-      }
-      return false;
+      if (!visitInitializer(Init))
+        return false;
+
+      return this->emitFinishInitPop(Init);
     }
-    return true;
+    return false;
   }
-
-  return false;
+  return true;
 }
 
 template <class Emitter>
@@ -4751,8 +4744,10 @@ bool Compiler<Emitter>::visitAPValue(const APValue &Val, PrimType ValType,
   assert(!DiscardResult);
   if (Val.isInt())
     return this->emitConst(Val.getInt(), ValType, E);
-  else if (Val.isFloat())
-    return this->emitConstFloat(Val.getFloat(), E);
+  else if (Val.isFloat()) {
+    APFloat F = Val.getFloat();
+    return this->emitFloat(F, E);
+  }
 
   if (Val.isLValue()) {
     if (Val.isNullPointer())
@@ -6133,8 +6128,10 @@ bool Compiler<Emitter>::VisitUnaryOperator(const UnaryOperator *E) {
       const auto &TargetSemantics = Ctx.getFloatSemantics(E->getType());
       if (!this->emitLoadFloat(E))
         return false;
-      if (!this->emitConstFloat(llvm::APFloat(TargetSemantics, 1), E))
+      APFloat F(TargetSemantics, 1);
+      if (!this->emitFloat(F, E))
         return false;
+
       if (!this->emitAddf(getFPOptions(E), E))
         return false;
       if (!this->emitStoreFloat(E))
@@ -6176,8 +6173,10 @@ bool Compiler<Emitter>::VisitUnaryOperator(const UnaryOperator *E) {
       const auto &TargetSemantics = Ctx.getFloatSemantics(E->getType());
       if (!this->emitLoadFloat(E))
         return false;
-      if (!this->emitConstFloat(llvm::APFloat(TargetSemantics, 1), E))
+      APFloat F(TargetSemantics, 1);
+      if (!this->emitFloat(F, E))
         return false;
+
       if (!this->emitSubf(getFPOptions(E), E))
         return false;
       if (!this->emitStoreFloat(E))
@@ -6953,6 +6952,20 @@ bool Compiler<Emitter>::emitDummyPtr(const DeclTy &D, const Expr *E) {
   return true;
 }
 
+template <class Emitter>
+bool Compiler<Emitter>::emitFloat(const APFloat &F, const Expr *E) {
+  assert(!DiscardResult && "Should've been checked before");
+
+  if (Floating::singleWord(F.getSemantics()))
+    return this->emitConstFloat(Floating(F), E);
+
+  APInt I = F.bitcastToAPInt();
+  return this->emitConstFloat(
+      Floating(const_cast<uint64_t *>(I.getRawData()),
+               llvm::APFloatBase::SemanticsToEnum(F.getSemantics())),
+      E);
+}
+
 //  This function is constexpr if and only if To, From, and the types of
 //  all subobjects of To and From are types T such that...
 //  (3.1) - is_union_v<T> is false;