merge main into amd-staging (llvm#836)

Author: ronlieb

clang/lib/AST/ByteCode/Compiler.cpp

@@ -1674,6 +1674,7 @@ bool Compiler<Emitter>::VisitArraySubscriptExpr(const ArraySubscriptExpr *E) {
   const Expr *LHS = E->getLHS();
   const Expr *RHS = E->getRHS();
   const Expr *Index = E->getIdx();
+  const Expr *Base = E->getBase();
 
   if (DiscardResult)
     return this->discard(LHS) && this->discard(RHS);
@@ -1682,8 +1683,17 @@ bool Compiler<Emitter>::VisitArraySubscriptExpr(const ArraySubscriptExpr *E) {
   // side is the base.
   bool Success = true;
   for (const Expr *SubExpr : {LHS, RHS}) {
-    if (!this->visit(SubExpr))
+    if (!this->visit(SubExpr)) {
       Success = false;
+      continue;
+    }
+
+    // Expand the base if this is a subscript on a
+    // pointer expression.
+    if (SubExpr == Base && Base->getType()->isPointerType()) {
+      if (!this->emitExpandPtr(E))
+        Success = false;
+    }
   }
 
   if (!Success)

clang/lib/AST/ByteCode/Interp.cpp

@@ -139,17 +139,19 @@ static bool CheckActive(InterpState &S, CodePtr OpPC, const Pointer &Ptr,
 
   Pointer U = Ptr.getBase();
   Pointer C = Ptr;
-  while (!U.isRoot() && U.inUnion() && !U.isActive()) {
-    if (U.getField())
-      C = U;
+  while (!U.isRoot() && !U.isActive()) {
+    // A little arbitrary, but this is what the current interpreter does.
+    // See the AnonymousUnion test in test/AST/ByteCode/unions.cpp.
+    // GCC's output is more similar to what we would get without
+    // this condition.
+    if (U.getRecord() && U.getRecord()->isAnonymousUnion())
+      break;
+
+    C = U;
     U = U.getBase();
   }
   assert(C.isField());
 
-  // Get the inactive field descriptor.
-  const FieldDecl *InactiveField = C.getField();
-  assert(InactiveField);
-
   // Consider:
   // union U {
   //   struct {
@@ -165,6 +167,11 @@ static bool CheckActive(InterpState &S, CodePtr OpPC, const Pointer &Ptr,
   if (!U.getFieldDesc()->isUnion())
     return true;
 
+  // Get the inactive field descriptor.
+  assert(!C.isActive());
+  const FieldDecl *InactiveField = C.getField();
+  assert(InactiveField);
+
   // Find the active field of the union.
   const Record *R = U.getRecord();
   assert(R && R->isUnion() && "Not a union");

clang/lib/AST/ByteCode/Interp.h

@@ -2589,7 +2589,10 @@ inline bool NarrowPtr(InterpState &S, CodePtr OpPC) {
 
 inline bool ExpandPtr(InterpState &S, CodePtr OpPC) {
   const Pointer &Ptr = S.Stk.pop<Pointer>();
-  S.Stk.push<Pointer>(Ptr.expand());
+  if (Ptr.isBlockPointer())
+    S.Stk.push<Pointer>(Ptr.expand());
+  else
+    S.Stk.push<Pointer>(Ptr);
   return true;
 }
 

clang/lib/AST/ByteCode/Pointer.cpp

@@ -437,28 +437,35 @@ void Pointer::activate() const {
   if (!getInlineDesc()->InUnion)
     return;
 
-  getInlineDesc()->IsActive = true;
+  auto activate = [](Pointer &P) -> void {
+    P.getInlineDesc()->IsActive = true;
+  };
+  auto deactivate = [](Pointer &P) -> void {
+    P.getInlineDesc()->IsActive = false;
+  };
 
-  // Get the union, iterate over its fields and DEactivate all others.
+  // Unions might be nested etc., so find the topmost Pointer that's
+  // not in a union anymore.
   Pointer UnionPtr = getBase();
-  while (!UnionPtr.getFieldDesc()->isUnion())
+  while (!UnionPtr.isRoot() && UnionPtr.inUnion())
     UnionPtr = UnionPtr.getBase();
 
+  assert(UnionPtr.getFieldDesc()->isUnion());
+
   const Record *UnionRecord = UnionPtr.getRecord();
   for (const Record::Field &F : UnionRecord->fields()) {
     Pointer FieldPtr = UnionPtr.atField(F.Offset);
     if (FieldPtr == *this) {
     } else {
-      FieldPtr.getInlineDesc()->IsActive = false;
+      deactivate(FieldPtr);
       // FIXME: Recurse.
     }
   }
 
-  Pointer B = getBase();
-  while (!B.isRoot() && B.inUnion()) {
+  Pointer B = *this;
+  while (B != UnionPtr) {
+    activate(B);
     // FIXME: Need to de-activate other fields of parent records.
-    B.getInlineDesc()->IsActive = true;
-    assert(B.isActive());
     B = B.getBase();
   }
 }

clang/lib/AST/ByteCode/Pointer.h

@@ -494,9 +494,6 @@ class Pointer {
   /// Returns the field information.
   const FieldDecl *getField() const { return getFieldDesc()->asFieldDecl(); }
 
-  /// Checks if the object is a union.
-  bool isUnion() const;
-
   /// Checks if the storage is extern.
   bool isExtern() const {
     if (isBlockPointer())

clang/lib/Headers/cpuid.h

@@ -267,18 +267,18 @@
                   : "0"(__leaf), "2"(__count))
 #else
 /* x86-64 uses %rbx as the base register, so preserve it. */
-#define __cpuid(__leaf, __eax, __ebx, __ecx, __edx) \
-    __asm("  xchgq  %%rbx,%q1\n" \
-          "  cpuid\n" \
-          "  xchgq  %%rbx,%q1" \
-        : "=a"(__eax), "=r" (__ebx), "=c"(__ecx), "=d"(__edx) \
+#define __cpuid(__leaf, __eax, __ebx, __ecx, __edx)                            \
+  __asm("  xchg{q|}  {%%|}rbx,%q1\n"                                           \
+        "  cpuid\n"                                                            \
+        "  xchg{q|}  {%%|}rbx,%q1"                                             \
+        : "=a"(__eax), "=r"(__ebx), "=c"(__ecx), "=d"(__edx)                   \
         : "0"(__leaf))
 
-#define __cpuid_count(__leaf, __count, __eax, __ebx, __ecx, __edx) \
-    __asm("  xchgq  %%rbx,%q1\n" \
-          "  cpuid\n" \
-          "  xchgq  %%rbx,%q1" \
-        : "=a"(__eax), "=r" (__ebx), "=c"(__ecx), "=d"(__edx) \
+#define __cpuid_count(__leaf, __count, __eax, __ebx, __ecx, __edx)             \
+  __asm("  xchg{q|}  {%%|}rbx,%q1\n"                                           \
+        "  cpuid\n"                                                            \
+        "  xchg{q|}  {%%|}rbx,%q1"                                             \
+        : "=a"(__eax), "=r"(__ebx), "=c"(__ecx), "=d"(__edx)                   \
         : "0"(__leaf), "2"(__count))
 #endif
 
@@ -289,20 +289,22 @@ static __inline unsigned int __get_cpuid_max (unsigned int __leaf,
 #ifdef __i386__
     int __cpuid_supported;
 
-    __asm("  pushfl\n"
-          "  popl   %%eax\n"
-          "  movl   %%eax,%%ecx\n"
-          "  xorl   $0x00200000,%%eax\n"
-          "  pushl  %%eax\n"
-          "  popfl\n"
-          "  pushfl\n"
-          "  popl   %%eax\n"
-          "  movl   $0,%0\n"
-          "  cmpl   %%eax,%%ecx\n"
+    __asm("  pushf{l|d}\n"
+          "  pop{l|}   {%%|}eax\n"
+          "  mov{l|}   {%%eax,%%ecx|ecx,eax}\n"
+          "  xor{l|}   {$0x00200000,%%eax|eax,0x00200000}\n"
+          "  push{l|}  {%%|}eax\n"
+          "  popf{l|d}\n"
+          "  pushf{l|d}\n"
+          "  pop{l|}   {%%|}eax\n"
+          "  mov{l|}   {$0,%0|%0,0}\n"
+          "  cmp{l|}   {%%eax,%%ecx|ecx,eax}\n"
           "  je     1f\n"
-          "  movl   $1,%0\n"
+          "  mov{l|}   {$1,%0|%0,1}\n"
           "1:"
-        : "=r" (__cpuid_supported) : : "eax", "ecx");
+          : "=r"(__cpuid_supported)
+          :
+          : "eax", "ecx");
     if (!__cpuid_supported)
         return 0;
 #endif

clang/lib/StaticAnalyzer/Checkers/MacOSKeychainAPIChecker.cpp

@@ -314,7 +314,6 @@ void MacOSKeychainAPIChecker::checkPreStmt(const CallExpr *CE,
     RegionArgIsBad = true;
   }
 
-  assert(ArgSM);
   // Is the argument to the call being tracked?
   const AllocationState *AS = State->get<AllocatedData>(ArgSM);
   if (!AS)

clang/test/AST/ByteCode/arrays.cpp

@@ -662,3 +662,16 @@ namespace InvalidIndex {
   }
   static_assert(foo(0) == 1, "");
 }
+
+namespace PointerSubscript {
+  template<typename T>
+  constexpr T foo() {
+    T ss[] = {{}, {}, {}};
+    T *s = &ss[0];
+
+    return s[2];
+  }
+  static_assert(foo<int>() == 0);
+  struct S{};
+  static_assert((foo<S>(), true));
+}

clang/test/AST/ByteCode/libcxx/pointer-subscript.cpp

@@ -0,0 +1,36 @@
+// RUN: %clang_cc1 -std=c++2c -fexperimental-new-constant-interpreter -verify=expected,both %s
+// RUN: %clang_cc1 -std=c++2c  -verify=ref,both %s
+
+// both-no-diagnostics
+
+namespace std {
+inline namespace __1 {
+template <class _Tp> class unique_ptr;
+template <class _Tp> class unique_ptr<_Tp[]> {
+public:
+  _Tp* __ptr_;
+
+public:
+  constexpr _Tp&
+  operator[](unsigned i) const {
+    return __ptr_[i];
+  };
+};
+} // namespace __1
+} // namespace std
+struct WithTrivialDtor {
+  int x = 6;
+  constexpr friend void operator==(WithTrivialDtor const &x,
+                                   WithTrivialDtor const &y) {
+    (void)(x.x == y.x);
+  }
+};
+constexpr bool test() {
+
+  WithTrivialDtor array[50];
+  std::unique_ptr<WithTrivialDtor[]> p(&array[0]);
+  (void)(p[1] == WithTrivialDtor());
+
+  return true;
+}
+static_assert(test());

clang/test/AST/ByteCode/unions.cpp

@@ -485,4 +485,23 @@ namespace IFD {
   }
   static_assert(test());
 }
+
+namespace AnonymousUnion {
+  struct A {
+    int x;
+    union { int p, q; };
+  };
+  union B {
+    A a;
+    int bb;
+  };
+
+  constexpr B return_init_all() {
+    B b = {.bb = 1};
+    b.a.x = 2;
+    return b;
+  }
+  static_assert(return_init_all().a.p == 7); // both-error {{}} \
+                                             // both-note {{read of member 'p' of union with no active member}}
+}
 #endif