From: Elizabeth Andrews <elizabeth.andrews@intel.com>
Date: Tue, 13 Aug 2019 15:53:19 +0000 (+0000)
Subject: Fix crash on switch conditions of non-integer types in templates
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=318c63ccf2beb63e6f49c990eb3754180d36800b;p=clang

Fix crash on switch conditions of non-integer types in templates

Clang currently crashes for switch statements inside a template when
the condition is a non-integer field. The crash is due to incorrect
type-dependency of field. Type-dependency of member expressions is
currently set based on the containing class. This patch changes this for
'members of the current instantiation' to set the type dependency based
on the member's type instead.

A few lit tests started to fail once I applied this patch because errors
are now diagnosed earlier (does not wait till instantiation). I've modified
these tests in this patch as well.

Patch fixes PR#40982

Differential Revision: https://reviews.llvm.org/D61027

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@368706 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index d2730d3e26..70bd42cfa5 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -1669,6 +1669,15 @@ MemberExpr *MemberExpr::Create(
   MemberExpr *E = new (Mem) MemberExpr(Base, IsArrow, OperatorLoc, MemberDecl,
                                        NameInfo, T, VK, OK, NOUR);
 
+  if (FieldDecl *Field = dyn_cast<FieldDecl>(MemberDecl)) {
+    DeclContext *DC = MemberDecl->getDeclContext();
+    // dyn_cast_or_null is used to handle objC variables which do not
+    // have a declaration context.
+    CXXRecordDecl *RD = dyn_cast_or_null<CXXRecordDecl>(DC);
+    if (RD && RD->isDependentContext() && RD->isCurrentInstantiation(DC))
+      E->setTypeDependent(T->isDependentType());
+  }
+
   if (HasQualOrFound) {
     // FIXME: Wrong. We should be looking at the member declaration we found.
     if (QualifierLoc && QualifierLoc.getNestedNameSpecifier()->isDependent()) {
diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index 3225dffe92..9df5599728 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -14288,6 +14288,8 @@ void Sema::RefersToMemberWithReducedAlignment(
   bool AnyIsPacked = false;
   do {
     QualType BaseType = ME->getBase()->getType();
+    if (BaseType->isDependentType())
+      return;
     if (ME->isArrow())
       BaseType = BaseType->getPointeeType();
     RecordDecl *RD = BaseType->getAs<RecordType>()->getDecl();
diff --git a/test/SemaTemplate/dependent-names.cpp b/test/SemaTemplate/dependent-names.cpp
index 67ef238083..a8de159a1d 100644
--- a/test/SemaTemplate/dependent-names.cpp
+++ b/test/SemaTemplate/dependent-names.cpp
@@ -273,9 +273,6 @@ namespace PR10187 {
       }
       int e[10];
     };
-    void g() {
-      S<int>().f(); // expected-note {{here}}
-    }
   }
 
   namespace A2 {
diff --git a/test/SemaTemplate/enum-argument.cpp b/test/SemaTemplate/enum-argument.cpp
index 7ff4196139..a79ed8403e 100644
--- a/test/SemaTemplate/enum-argument.cpp
+++ b/test/SemaTemplate/enum-argument.cpp
@@ -1,5 +1,4 @@
 // RUN: %clang_cc1 -fsyntax-only -verify %s
-// expected-no-diagnostics
 
 enum Enum { val = 1 };
 template <Enum v> struct C {
@@ -31,7 +30,7 @@ namespace rdar8020920 {
     unsigned long long bitfield : e0;
 
     void f(int j) {
-      bitfield + j;
+      bitfield + j; // expected-warning {{expression result unused}}
     }
   };
 }
diff --git a/test/SemaTemplate/member-access-expr.cpp b/test/SemaTemplate/member-access-expr.cpp
index 8dba2e68d6..ef10d72a0e 100644
--- a/test/SemaTemplate/member-access-expr.cpp
+++ b/test/SemaTemplate/member-access-expr.cpp
@@ -156,7 +156,7 @@ namespace test6 {
     void get(B **ptr) {
       // It's okay if at some point we figure out how to diagnose this
       // at instantiation time.
-      *ptr = field;
+      *ptr = field; // expected-error {{assigning to 'test6::B *' from incompatible type 'test6::A *}}
     }
   };
 }
diff --git a/test/SemaTemplate/non-integral-switch-cond.cpp b/test/SemaTemplate/non-integral-switch-cond.cpp
new file mode 100644
index 0000000000..23c8e0ef8d
--- /dev/null
+++ b/test/SemaTemplate/non-integral-switch-cond.cpp
@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+struct NOT_AN_INTEGRAL_TYPE {};
+
+template <typename T>
+struct foo {
+  NOT_AN_INTEGRAL_TYPE Bad;
+  void run() {
+    switch (Bad) { // expected-error {{statement requires expression of integer type ('NOT_AN_INTEGRAL_TYPE' invalid)}}
+    case 0:
+      break;
+    }
+  }
+};