[PATCH] D120936: [Sema][Windows] Don't special-case void* in __unaligned conversions.

[Eli Friedman via Phabricator via cfe-commits]

efriedma created this revision.
efriedma added reviewers: rnk, mstorsjo, andreybokhanko, majnemer, aaron.ballman.
Herald added a project: All.
efriedma requested review of this revision.
Herald added a project: clang.

As far as I can tell, MSVC allows the relevant conversions for all pointer types.  Found compiling a Windows SDK header.

I've verified that the updated errors in MicrosoftExtensions.cpp match the ones that MSVC actually emits, except for the one with a FIXME.  (Not sure why this wasn't done for the patch that added the tests.)


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D120936

Files:
  clang/lib/Sema/SemaOverload.cpp
  clang/test/SemaCXX/MicrosoftExtensions.cpp


Index: clang/test/SemaCXX/MicrosoftExtensions.cpp
===================================================================
--- clang/test/SemaCXX/MicrosoftExtensions.cpp
+++ clang/test/SemaCXX/MicrosoftExtensions.cpp
@@ -85,18 +85,18 @@
   foo_unaligned(p2);
 
   __unaligned B_unaligned *p3 = 0;
-  int p4 = foo_unaligned(p3);
+  int p4 = foo_unaligned(p3); // expected-error {{cannot initialize a variable of type 'int' with an rvalue of type 'void *'}}
 
-  B_unaligned *p5 = p3; // expected-error {{cannot initialize a variable of type 'B_unaligned *' with an lvalue of type '__unaligned B_unaligned *'}}
+  B_unaligned *p5 = p3;
 
   __unaligned B_unaligned *p6 = p3;
 
   p1_aligned_type4 = p2_aligned_type4;
-  p2_aligned_type4 = p1_aligned_type4; // expected-error {{assigning to 'int aligned_type4::*' from incompatible type '__unaligned int aligned_type4::*'}}
+  p2_aligned_type4 = p1_aligned_type4;
   p3_aligned_type4 = p1_aligned_type4;
 
   __unaligned int a[10];
-  int *b = a; // expected-error {{cannot initialize a variable of type 'int *' with an lvalue of type '__unaligned int[10]'}}
+  int *b = a;
 }
 
 // Test from PR27367
@@ -115,13 +115,15 @@
 // We should accept type conversion of __unaligned to non-__unaligned references
 typedef struct in_addr {
 public:
-  in_addr(in_addr &a) {} // expected-note {{candidate constructor not viable: no known conversion from '__unaligned IN_ADDR *' (aka '__unaligned in_addr *') to 'in_addr &' for 1st argument; dereference the argument with *}}
-  in_addr(in_addr *a) {} // expected-note {{candidate constructor not viable: 1st argument ('__unaligned IN_ADDR *' (aka '__unaligned in_addr *')) would lose __unaligned qualifier}}
+  in_addr(in_addr &a) {} // expected-note {{candidate constructor not viable: expects an lvalue for 1st argument}}
+  in_addr(in_addr *a) {} // expected-note {{candidate constructor not viable: no known conversion from 'IN_ADDR' (aka 'in_addr') to 'in_addr *' for 1st argument}}
 } IN_ADDR;
 
 void f(IN_ADDR __unaligned *a) {
   IN_ADDR local_addr = *a;
-  IN_ADDR local_addr2 = a; // expected-error {{no viable conversion from '__unaligned IN_ADDR *' (aka '__unaligned in_addr *') to 'IN_ADDR' (aka 'in_addr')}}
+  // FIXME: MSVC accepts the following; not sure why clang tries to
+  // copy-construct an in_addr.
+  IN_ADDR local_addr2 = a; // expected-error {{no viable constructor copying variable of type 'IN_ADDR' (aka 'in_addr')}}
 }
 
 template<typename T> void h1(T (__stdcall M::* const )()) { }
Index: clang/lib/Sema/SemaOverload.cpp
===================================================================
--- clang/lib/Sema/SemaOverload.cpp
+++ clang/lib/Sema/SemaOverload.cpp
@@ -3195,9 +3195,8 @@
   Qualifiers FromQuals = FromType.getQualifiers();
   Qualifiers ToQuals = ToType.getQualifiers();
 
-  // Ignore __unaligned qualifier if this type is void.
-  if (ToType.getUnqualifiedType()->isVoidType())
-    FromQuals.removeUnaligned();
+  // Ignore __unaligned qualifier.
+  FromQuals.removeUnaligned();
 
   // Objective-C ARC:
   //   Check Objective-C lifetime conversions.


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