[llvm-branch-commits] [clang] 104dfd2 - Initial implementation of corrected fix

Zarko Todorovski via llvm-branch-commits llvm-branch-commits at lists.llvm.org
Wed Jan 26 19:17:32 PST 2022


Author: Zarko Todorovski
Date: 2022-01-26T22:16:52-05:00
New Revision: 104dfd2b26361f1caf2ad116cbc709c49355da75

URL: https://github.com/llvm/llvm-project/commit/104dfd2b26361f1caf2ad116cbc709c49355da75
DIFF: https://github.com/llvm/llvm-project/commit/104dfd2b26361f1caf2ad116cbc709c49355da75.diff

LOG: Initial implementation of corrected fix

Added: 
    

Modified: 
    clang/include/clang/Sema/Sema.h
    clang/lib/Sema/SemaChecking.cpp
    clang/lib/Sema/SemaDeclAttr.cpp
    clang/test/Sema/aix-attr-align.c

Removed: 
    


################################################################################
diff  --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index 4b609f4b1477c..c5ed62943e320 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -12691,7 +12691,7 @@ class Sema final {
                             const FunctionProtoType *Proto, SourceLocation Loc);
 
   void CheckArgAlignment(SourceLocation Loc, NamedDecl *FDecl,
-                         StringRef ParamName, QualType ArgTy, QualType ParamTy);
+                         StringRef ParamName, QualType ArgTy, QualType ParamTy, const Expr* Arg = nullptr);
 
   void checkCall(NamedDecl *FDecl, const FunctionProtoType *Proto,
                  const Expr *ThisArg, ArrayRef<const Expr *> Args,

diff  --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index c8fb36b8311a4..fc78d9071fbb5 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -5207,7 +5207,37 @@ static void CheckNonNullArguments(Sema &S,
 /// calling functions defined in terms of the original type.
 void Sema::CheckArgAlignment(SourceLocation Loc, NamedDecl *FDecl,
                              StringRef ParamName, QualType ArgTy,
-                             QualType ParamTy) {
+                             QualType ParamTy, const Expr* Arg) {
+
+  // 16 byte ByVal alignment not due to a vector member is not honoured by XL
+  // on AIX. Emit a warning here that users are generating binary incompatible
+  // code to be safe.
+  // Here we try to get information about the alignment of the struct member
+  // argument passed to function.
+  if (Context.getTargetInfo().getTriple().isOSAIX()) {
+    if (Arg->IgnoreParens()) {
+      // Using AArg so as to not modify Arg for the rest of the function.
+      const Expr *AArg = Arg->IgnoreParens();
+      if (AArg->getStmtClass() == Stmt::ImplicitCastExprClass) {
+        const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(AArg);
+        AArg = ICE->getSubExpr();
+        if (AArg->getStmtClass() == Stmt::MemberExprClass) {
+          const auto *ME = dyn_cast<MemberExpr>(AArg);
+          ValueDecl *MD = ME->getMemberDecl();
+          auto *FD = dyn_cast<FieldDecl>(MD);
+          if (FD) {
+            if (FD->hasAttr<AlignedAttr>()) {
+              auto *AA = FD->getAttr<AlignedAttr>();
+              unsigned Aligned = AA->getAlignment(Context);
+              // Divide by 8 to get the bytes instead of using bits.
+              if (Aligned / 8 >= 16)
+                Diag(Loc, diag::warn_not_xl_compatible) << FD;
+            }
+          }
+        }
+      }
+    }
+  }
 
   // If a function accepts a pointer or reference type
   if (!ParamTy->isPointerType() && !ParamTy->isReferenceType())
@@ -5314,7 +5344,7 @@ void Sema::checkCall(NamedDecl *FDecl, const FunctionProtoType *Proto,
         QualType ParamTy = Proto->getParamType(ArgIdx);
         QualType ArgTy = Arg->getType();
         CheckArgAlignment(Arg->getExprLoc(), FDecl, std::to_string(ArgIdx + 1),
-                          ArgTy, ParamTy);
+                          ArgTy, ParamTy, Arg);
       }
     }
   }
@@ -5352,7 +5382,7 @@ void Sema::CheckConstructorCall(FunctionDecl *FDecl, QualType ThisType,
 
   auto *Ctor = cast<CXXConstructorDecl>(FDecl);
   CheckArgAlignment(Loc, FDecl, "'this'", Context.getPointerType(ThisType),
-                    Context.getPointerType(Ctor->getThisObjectType()));
+                    Context.getPointerType(Ctor->getThisObjectType()), nullptr);
 
   checkCall(FDecl, Proto, /*ThisArg=*/nullptr, Args, /*IsMemberFunction=*/true,
             Loc, SourceRange(), CallType);
@@ -5396,7 +5426,7 @@ bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall,
         Context.getPointerType(cast<CXXMethodDecl>(FDecl)->getThisObjectType());
 
     CheckArgAlignment(TheCall->getRParenLoc(), FDecl, "'this'", ThisType,
-                      ThisTypeFromDecl);
+                      ThisTypeFromDecl, nullptr);
   }
 
   checkCall(FDecl, Proto, ImplicitThis, llvm::makeArrayRef(Args, NumArgs),

diff  --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index 955f477760429..61c30a0f34216 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -4320,13 +4320,6 @@ void Sema::AddAlignedAttr(Decl *D, const AttributeCommonInfo &CI, Expr *E,
     return;
 
   uint64_t AlignVal = Alignment.getZExtValue();
-  // 16 byte ByVal alignment not due to a vector member is not honoured by XL
-  // on AIX. Emit a warning here that users are generating binary incompatible
-  // code to be safe.
-  if (AlignVal >= 16 && isa<FieldDecl>(D) &&
-      Context.getTargetInfo().getTriple().isOSAIX())
-    Diag(AttrLoc, diag::warn_not_xl_compatible) << E->getSourceRange();
-
   // C++11 [dcl.align]p2:
   //   -- if the constant expression evaluates to zero, the alignment
   //      specifier shall have no effect

diff  --git a/clang/test/Sema/aix-attr-align.c b/clang/test/Sema/aix-attr-align.c
index 0fd6af4ee4c13..5da8ab7890946 100644
--- a/clang/test/Sema/aix-attr-align.c
+++ b/clang/test/Sema/aix-attr-align.c
@@ -6,17 +6,31 @@
 // RUN: %clang_cc1 -triple powerpc64le-unknown-linux -verify=off -fsyntax-only %s
 
 struct S {
-  int a[8] __attribute__((aligned(8))); // no-warning
+  int a[8] __attribute__((aligned(8)));  // no-warning
+  int b[8] __attribute__((aligned(16))); // no-warning
+  int c[2] __attribute__((aligned(32))); // no-warning
 };
 
 struct T {
-  int a[4] __attribute__((aligned(16))); // expected-warning {{requesting an alignment of 16 bytes or greater for struct members is not binary compatible with IBM XL C/C++ for AIX 16.1.0 and older}}
+  int a[4] __attribute__((aligned(16))); // no-warning
 };
 
 struct U {
-  int a[2] __attribute__((aligned(32))); // expected-warning {{requesting an alignment of 16 bytes or greater for struct members is not binary compatible with IBM XL C/C++ for AIX 16.1.0 and older}}
+  int a[2] __attribute__((aligned(32))); // no-warning
 };
 
 int a[8] __attribute__((aligned(8)));  // no-warning
 int b[4] __attribute__((aligned(16))); // no-warning
 int c[2] __attribute__((aligned(32))); // no-warning
+
+void baz(int *);
+void foo(int p1, int p2, int p3, int p4, int p5, int p6, int p7, int p8,
+         struct S s) {
+  baz(s.a); // no-warning
+  baz(s.b); // expected-warning {{requesting an alignment of 16 bytes or greater for struct members is not binary compatible with IBM XL C/C++ for AIX 16.1.0 and older}}
+  baz(s.c); // expected-warning {{requesting an alignment of 16 bytes or greater for struct members is not binary compatible with IBM XL C/C++ for AIX 16.1.0 and older}}
+
+  baz(a); // no-warning
+  baz(b); // no-warning
+  baz(c); // no-warning
+}


        


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