[clang] 0a8ac91 - Permit nowthrow and nonnull with multiversioning.

[Erich Keane via cfe-commits]

Author: Erich Keane
Date: 2020-08-04T07:40:27-07:00
New Revision: 0a8ac91a084504929b1ef4ec1fee693455bd796d

URL: https://github.com/llvm/llvm-project/commit/0a8ac91a084504929b1ef4ec1fee693455bd796d
DIFF: https://github.com/llvm/llvm-project/commit/0a8ac91a084504929b1ef4ec1fee693455bd796d.diff

LOG: Permit nowthrow and nonnull with multiversioning.

Some shipped versions of stdlib.h use nonnull and nothrow with function
multiversioning.  Support these, as they are generally harmless.

Added: 
    

Modified: 
    clang/include/clang/Basic/DiagnosticSemaKinds.td
    clang/lib/Sema/SemaDecl.cpp
    clang/test/Sema/attr-cpuspecific.c
    clang/test/Sema/attr-target-mv.c

Removed: 
    


################################################################################
diff  --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 288e8232ca74..054b81c4a72b 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -10754,6 +10754,9 @@ def err_multiversion_noproto : Error<
 def err_multiversion_disallowed_other_attr : Error<
   "attribute '%select{target|cpu_specific|cpu_dispatch}0' multiversioning cannot be combined"
   " with attribute %1">;
+def err_multiversion_mismatched_attrs
+    : Error<"attributes on multiversioned functions must all match, attribute "
+            "%0 %select{is missing|has 
diff erent arguments}1">;
 def err_multiversion_
diff  : Error<
   "multiversioned function declaration has a 
diff erent %select{calling convention"
   "|return type|constexpr specification|inline specification|storage class|"

diff  --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index ba05b0d32cf4..77e15f187e53 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -10029,11 +10029,16 @@ static bool CheckMultiVersionValue(Sema &S, const FunctionDecl *FD) {
 // multiversion functions.
 static bool AttrCompatibleWithMultiVersion(attr::Kind Kind,
                                            MultiVersionKind MVType) {
+  // Note: this list/diagnosis must match the list in
+  // checkMultiversionAttributesAllSame.
   switch (Kind) {
   default:
     return false;
   case attr::Used:
     return MVType == MultiVersionKind::Target;
+  case attr::NonNull:
+  case attr::NoThrow:
+    return true;
   }
 }
 
@@ -10201,8 +10206,6 @@ static bool CheckMultiVersionAdditionalRules(Sema &S, const FunctionDecl *OldFD,
       MVType == MultiVersionKind::CPUDispatch ||
       MVType == MultiVersionKind::CPUSpecific;
 
-  // For now, disallow all other attributes.  These should be opt-in, but
-  // an analysis of all of them is a future FIXME.
   if (CausesMV && OldFD &&
       checkNonMultiVersionCompatAttributes(S, OldFD, NewFD, MVType))
     return true;

diff  --git a/clang/test/Sema/attr-cpuspecific.c b/clang/test/Sema/attr-cpuspecific.c
index e32c7a22894d..9cfeef8a2356 100644
--- a/clang/test/Sema/attr-cpuspecific.c
+++ b/clang/test/Sema/attr-cpuspecific.c
@@ -115,3 +115,5 @@ int use3(void) {
 
 // expected-warning at +1 {{CPU list contains duplicate entries; attribute ignored}}
 int __attribute__((cpu_dispatch(pentium_iii, pentium_iii_no_xmm_regs))) dupe_p3(void);
+
+void __attribute__((cpu_specific(atom), nothrow, nonnull(1))) addtl_attrs(int*);

diff  --git a/clang/test/Sema/attr-target-mv.c b/clang/test/Sema/attr-target-mv.c
index 33a2c4fa54eb..3f072b19083f 100644
--- a/clang/test/Sema/attr-target-mv.c
+++ b/clang/test/Sema/attr-target-mv.c
@@ -101,3 +101,10 @@ __vectorcall int __attribute__((target("arch=sandybridge")))  
diff _cc(void);
 int __attribute__((target("sse4.2"))) 
diff _ret(void);
 // expected-error at +1 {{multiversioned function declaration has a 
diff erent return type}}
 short __attribute__((target("arch=sandybridge")))  
diff _ret(void);
+
+void __attribute__((target("sse4.2"), nothrow, used, nonnull(1))) addtl_attrs5(int*);
+void __attribute__((target("arch=sandybridge"))) addtl_attrs5(int*);
+
+void __attribute__((target("sse4.2"))) addtl_attrs6(int*);
+void __attribute__((target("arch=sandybridge"), nothrow, used, nonnull)) addtl_attrs6(int*);
+