[clang] 7692fc8 - Revert "[randstruct] Enforce using a designated init for a randomized struct"

[Aaron Ballman via cfe-commits]

Author: Aaron Ballman
Date: 2022-04-16T11:11:32-04:00
New Revision: 7692fc81e016a5674464fa77732bd1c7a3903f17

URL: https://github.com/llvm/llvm-project/commit/7692fc81e016a5674464fa77732bd1c7a3903f17
DIFF: https://github.com/llvm/llvm-project/commit/7692fc81e016a5674464fa77732bd1c7a3903f17.diff

LOG: Revert "[randstruct] Enforce using a designated init for a randomized struct"

This reverts commit aed923b1246ac38335b222b89594516fcf0d6385.

It causes some buildbot test failures.

Added: 
    

Modified: 
    clang/include/clang/Basic/DiagnosticSemaKinds.td
    clang/lib/Sema/SemaInit.cpp

Removed: 
    clang/test/Sema/init-randomized-struct.c


################################################################################
diff  --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index e79a40d62381f..a14194d271a71 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -11602,9 +11602,7 @@ def err_hlsl_pointers_unsupported : Error<
 def err_hlsl_operator_unsupported : Error<
   "the '%select{&|*|->}0' operator is unsupported in HLSL">;
 
-// Layout randomization diagnostics.
-def err_non_designated_init_used : Error<
-  "a randomized struct can only be initialized with a designated initializer">;
+// Layout randomization warning.
 def err_cast_from_randomized_struct : Error<
   "casting from randomized structure pointer type %0 to %1">;
 } // end of sema component.

diff  --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index 233be547bf118..c3bbefbaaed1b 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -2123,7 +2123,6 @@ void InitListChecker::CheckStructUnionTypes(
   // worthwhile to skip over the rest of the initializer, though.
   RecordDecl *RD = DeclType->castAs<RecordType>()->getDecl();
   RecordDecl::field_iterator FieldEnd = RD->field_end();
-  size_t NumRecordFields = std::distance(RD->field_begin(), RD->field_end());
   bool CheckForMissingFields =
     !IList->isIdiomaticZeroInitializer(SemaRef.getLangOpts());
   bool HasDesignatedInit = false;
@@ -2173,35 +2172,6 @@ void InitListChecker::CheckStructUnionTypes(
       break;
     }
 
-    // Check if this is an initializer of forms:
-    //
-    //   struct foo f = {};
-    //   struct foo g = {0};
-    //
-    // These are okay for randomized structures. [C99 6.7.8p19]
-    //
-    // Also, if there is only one element in the structure, we allow something
-    // like this, because it's really not randomized in the tranditional sense.
-    //
-    //   struct foo h = {bar};
-    auto IsZeroInitializer = [&](const Expr *I) {
-      if (IList->getNumInits() == 1) {
-        if (NumRecordFields == 1)
-          return true;
-        if (const auto *IL = dyn_cast<IntegerLiteral>(I))
-          return IL->getValue().isZero();
-      }
-      return false;
-    };
-
-    // Don't allow non-designated initializers on randomized structures.
-    if (RD->isRandomized() && !IsZeroInitializer(Init)) {
-      if (!VerifyOnly)
-        SemaRef.Diag(InitLoc, diag::err_non_designated_init_used);
-      hadError = true;
-      break;
-    }
-
     // We've already initialized a member of a union. We're done.
     if (InitializedSomething && DeclType->isUnionType())
       break;

diff  --git a/clang/test/Sema/init-randomized-struct.c b/clang/test/Sema/init-randomized-struct.c
deleted file mode 100644
index 87842e1f19e80..0000000000000
--- a/clang/test/Sema/init-randomized-struct.c
+++ /dev/null
@@ -1,56 +0,0 @@
-// RUN: %clang_cc1 %s -verify -fsyntax-only -frandomize-layout-seed=1234567890abcdef
-
-// Initializing a randomized structure requires a designated initializer,
-// otherwise the element ordering will be off. The only exceptions to this rule
-// are:
-//
-//    - A structure with only one element, and
-//    - A structure initialized with "{0}".
-//
-// These are well-defined situations where the field ordering doesn't affect
-// the result.
-
-typedef void (*func_ptr)();
-
-void foo(void);
-void bar(void);
-void baz(void);
-void gaz(void);
-
-struct test {
-  func_ptr a;
-  func_ptr b;
-  func_ptr c;
-  func_ptr d;
-  func_ptr e;
-  func_ptr f;
-  func_ptr g;
-} __attribute__((randomize_layout));
-
-struct test t1 = {}; // This should be fine per WG14 N2900 (in C23) + our extension handling of it in earlier modes
-struct test t2 = { 0 }; // This should also be fine per C99 6.7.8p19
-struct test t3 = { .f = baz, .b = bar, .g = gaz, .a = foo }; // Okay
-struct test t4 = { .a = foo, bar, baz }; // expected-error {{a randomized struct can only be initialized with a designated initializer}}
-
-struct other_test {
-  func_ptr a;
-  func_ptr b[3];
-  func_ptr c;
-} __attribute__((randomize_layout));
-
-struct other_test t5 = { .a = foo, .b[0] = foo }; // Okay
-struct other_test t6 = { .a = foo, .b[0] = foo, bar, baz }; // Okay
-struct other_test t7 = { .a = foo, .b = { foo, bar, baz } }; // Okay
-struct other_test t8 = { baz, bar, gaz, foo }; // expected-error {{a randomized struct can only be initialized with a designated initializer}}
-struct other_test t9 = { .a = foo, .b[0] = foo, bar, baz, gaz }; // expected-error {{a randomized struct can only be initialized with a designated initializer}}
-
-struct empty_test {
-} __attribute__((randomize_layout));
-
-struct empty_test t10 = {}; // Okay
-
-struct degen_test {
-  func_ptr a;
-} __attribute__((randomize_layout));
-
-struct degen_test t11 = { foo }; // Okay