Fix crash parsing invalid code

[ogoffart]

Summary

The code in the test caused a crash with this backtrace:

RecordLayoutBuilder.cpp:2934: const clang::ASTRecordLayout &clang::ASTContext::getASTRecordLayout(const clang::RecordDecl *) const: Assertion `!D->isInvalidDecl() && "Cannot get layout of invalid decl!"' failed.
[...]
#7 0x00007f63963d845a __assert_fail_base (/usr/lib/libc.so.6+0x2c45a)
#8 0x00007f63963d84d2 (/usr/lib/libc.so.6+0x2c4d2)
#9 0x00007f63937a0631 clang::ASTContext::getASTRecordLayout(clang::RecordDecl const*) const /home/olivier/prog/llvm/tools/clang/lib/AST/RecordLayoutBuilder.cpp:2935:3
#10 0x00007f63937a1ad5 getFieldOffset(clang::ASTContext const&, clang::FieldDecl const*) /home/olivier/prog/llvm/tools/clang/lib/AST/RecordLayoutBuilder.cpp:3057:37
#11 0x00007f6391869f14 clang::Sema::RefersToMemberWithReducedAlignment(clang::Expr*, llvm::function_ref<void (clang::Expr*, clang::RecordDecl*, clang::FieldDecl*, clang::CharUnits)>) /home/olivier/prog/llvm/tools/clang/lib/Sema/SemaChecking.cpp:12139:23
#12 0x00007f639186a2f8 clang::Sema::CheckAddressOfPackedMember(clang::Expr*) /home/olivier/prog/llvm/tools/clang/lib/Sema/SemaChecking.cpp:12190:1
#13 0x00007f6391a7a81c clang::Sema::CheckAddressOfOperand(clang::ActionResult<clang::Expr*, true>&, clang::SourceLocation) /home/olivier/prog/llvm/tools/clang/lib/Sema/SemaExpr.cpp:11111:10
#14 0x00007f6391a7f5d2 clang::Sema::CreateBuiltinUnaryOp(clang::SourceLocation, clang::UnaryOperatorKind, clang::Expr*) /home/olivier/prog/llvm/tools/clang/lib/Sema/SemaExpr.cpp:11932:18

Fixing by bailing out for invalid classes.

[rogfer01]

Hi @ogoffart thanks for fixing this.

I suggest some minor change for the check, other than that this looks good to me.

lib/Sema/SemaChecking.cpp

12099 ↗

(On Diff #105590)

Can you make the check for RD->isInvalidDecl() here instead?

if (RD->isInvalidDecl())
  return;

cfe/trunk/lib/Sema/SemaChecking.cpp

void Sema::RefersToMemberWithReducedAlignment(
   SmallVector<FieldDecl *, 4> ReverseMemberChain;
   const MemberExpr *TopME = nullptr;
   bool AnyIsPacked = false;
   do {
     QualType BaseType = ME->getBase()->getType();
     if (ME->isArrow())
       BaseType = BaseType->getPointeeType();
     RecordDecl *RD = BaseType->getAs<RecordType>()->getDecl();
+    if (RD->isInvalidDecl())
+      return;
 
     ValueDecl *MD = ME->getMemberDecl();
     auto *FD = dyn_cast<FieldDecl>(MD);
     // We do not care about non-data members.
     if (!FD || FD->isInvalidDecl())
       return;
 
     AnyIsPacked =

cfe/trunk/test/Sema/address-packed.c

struct S11 {
   uint32_t x;
 } __attribute__((__packed__));
 
 void g13(void) {
   struct S11 __attribute__((__aligned__(4))) a[4];
   uint32_t *p32;
   p32 = &a[0].x; // no-warning
 }
+
+struct Invalid0 {
+  void *x;
+  struct fwd f; // expected-error {{incomplete type}} expected-note {{forward declaration}}
+} __attribute__((packed));
+
+void *g14(struct Invalid0 *ivl) {
+  return &(ivl->x);
+}