Author: dim
Date: Fri Mar  6 17:02:14 2020
New Revision: 358711
URL: https://svnweb.freebsd.org/changeset/base/358711

Log:
  Merge commit f75939599 from llvm git (by Erich Keane):
  
    Reland r374450 with Richard Smith's comments and test fixed.
  
    The behavior from the original patch has changed, since we're no
    longer allowing LLVM to just ignore the alignment.  Instead, we're
    just assuming the maximum possible alignment.
  
    Differential Revision: https://reviews.llvm.org/D68824
  
    llvm-svn: 374562
  
  This fixes 'Assertion failed: (Alignment != 0 && "Invalid Alignment"),
  function CreateAlignmentAssumption', when building recent versions of
  v8, which invoke __builtin_assume_aligned() with its alignment argument
  set to 4GiB or more.
  
  Clang will now report a warning, and show the maximum possible alignment
  instead, e.g.:
  
  huge-align.cpp:1:27: warning: requested alignment must be 536870912 bytes or 
smaller; maximum alignment assumed [-Wbuiltin-assume-aligned-alignment]
  void *f(void *g) { return __builtin_assume_aligned(g, 4294967296); }
                            ^                           ~~~~~~~~~~
  
  Upstream PR:  https://bugs.llvm.org/show_bug.cgi?id=43839
  Reported by:  cem
  MFC after:    3 days

Modified:
  head/contrib/llvm-project/clang/include/clang/Basic/DiagnosticSemaKinds.td
  head/contrib/llvm-project/clang/lib/CodeGen/CGBuiltin.cpp
  head/contrib/llvm-project/clang/lib/CodeGen/CGCall.cpp
  head/contrib/llvm-project/clang/lib/CodeGen/CGExprScalar.cpp
  head/contrib/llvm-project/clang/lib/CodeGen/CGStmtOpenMP.cpp
  head/contrib/llvm-project/clang/lib/CodeGen/CodeGenFunction.cpp
  head/contrib/llvm-project/clang/lib/CodeGen/CodeGenFunction.h
  head/contrib/llvm-project/clang/lib/Sema/SemaChecking.cpp

Modified: 
head/contrib/llvm-project/clang/include/clang/Basic/DiagnosticSemaKinds.td
==============================================================================
--- head/contrib/llvm-project/clang/include/clang/Basic/DiagnosticSemaKinds.td  
Fri Mar  6 16:52:20 2020        (r358710)
+++ head/contrib/llvm-project/clang/include/clang/Basic/DiagnosticSemaKinds.td  
Fri Mar  6 17:02:14 2020        (r358711)
@@ -2797,6 +2797,10 @@ def err_alignment_dependent_typedef_name : Error<
 
 def err_attribute_aligned_too_great : Error<
   "requested alignment must be %0 bytes or smaller">;
+def warn_assume_aligned_too_great
+    : Warning<"requested alignment must be %0 bytes or smaller; maximum "
+              "alignment assumed">,
+      InGroup<DiagGroup<"builtin-assume-aligned-alignment">>;
 def warn_redeclaration_without_attribute_prev_attribute_ignored : Warning<
   "%q0 redeclared without %1 attribute: previous %1 ignored">,
   InGroup<MicrosoftInconsistentDllImport>;

Modified: head/contrib/llvm-project/clang/lib/CodeGen/CGBuiltin.cpp
==============================================================================
--- head/contrib/llvm-project/clang/lib/CodeGen/CGBuiltin.cpp   Fri Mar  6 
16:52:20 2020        (r358710)
+++ head/contrib/llvm-project/clang/lib/CodeGen/CGBuiltin.cpp   Fri Mar  6 
17:02:14 2020        (r358711)
@@ -2026,11 +2026,13 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDe
 
     Value *AlignmentValue = EmitScalarExpr(E->getArg(1));
     ConstantInt *AlignmentCI = cast<ConstantInt>(AlignmentValue);
-    unsigned Alignment = (unsigned)AlignmentCI->getZExtValue();
+    if (AlignmentCI->getValue().ugt(llvm::Value::MaximumAlignment))
+      AlignmentCI = ConstantInt::get(AlignmentCI->getType(),
+                                     llvm::Value::MaximumAlignment);
 
     EmitAlignmentAssumption(PtrValue, Ptr,
                             /*The expr loc is sufficient.*/ SourceLocation(),
-                            Alignment, OffsetValue);
+                            AlignmentCI, OffsetValue);
     return RValue::get(PtrValue);
   }
   case Builtin::BI__assume:

Modified: head/contrib/llvm-project/clang/lib/CodeGen/CGCall.cpp
==============================================================================
--- head/contrib/llvm-project/clang/lib/CodeGen/CGCall.cpp      Fri Mar  6 
16:52:20 2020        (r358710)
+++ head/contrib/llvm-project/clang/lib/CodeGen/CGCall.cpp      Fri Mar  6 
17:02:14 2020        (r358711)
@@ -4548,7 +4548,7 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo 
       llvm::Value *Alignment = EmitScalarExpr(AA->getAlignment());
       llvm::ConstantInt *AlignmentCI = cast<llvm::ConstantInt>(Alignment);
       EmitAlignmentAssumption(Ret.getScalarVal(), RetTy, Loc, 
AA->getLocation(),
-                              AlignmentCI->getZExtValue(), OffsetValue);
+                              AlignmentCI, OffsetValue);
     } else if (const auto *AA = TargetDecl->getAttr<AllocAlignAttr>()) {
       llvm::Value *AlignmentVal = CallArgs[AA->getParamIndex().getLLVMIndex()]
                                       .getRValue(*this)

Modified: head/contrib/llvm-project/clang/lib/CodeGen/CGExprScalar.cpp
==============================================================================
--- head/contrib/llvm-project/clang/lib/CodeGen/CGExprScalar.cpp        Fri Mar 
 6 16:52:20 2020        (r358710)
+++ head/contrib/llvm-project/clang/lib/CodeGen/CGExprScalar.cpp        Fri Mar 
 6 17:02:14 2020        (r358711)
@@ -294,8 +294,7 @@ class ScalarExprEmitter (public)
 
     Value *AlignmentValue = CGF.EmitScalarExpr(AVAttr->getAlignment());
     llvm::ConstantInt *AlignmentCI = cast<llvm::ConstantInt>(AlignmentValue);
-    CGF.EmitAlignmentAssumption(V, E, AVAttr->getLocation(),
-                                AlignmentCI->getZExtValue());
+    CGF.EmitAlignmentAssumption(V, E, AVAttr->getLocation(), AlignmentCI);
   }
 
   /// EmitLoadOfLValue - Given an expression with complex type that represents 
a

Modified: head/contrib/llvm-project/clang/lib/CodeGen/CGStmtOpenMP.cpp
==============================================================================
--- head/contrib/llvm-project/clang/lib/CodeGen/CGStmtOpenMP.cpp        Fri Mar 
 6 16:52:20 2020        (r358710)
+++ head/contrib/llvm-project/clang/lib/CodeGen/CGStmtOpenMP.cpp        Fri Mar 
 6 17:02:14 2020        (r358711)
@@ -1460,14 +1460,14 @@ static void emitAlignedClause(CodeGenFunction &CGF,
   if (!CGF.HaveInsertPoint())
     return;
   for (const auto *Clause : D.getClausesOfKind<OMPAlignedClause>()) {
-    unsigned ClauseAlignment = 0;
+    llvm::APInt ClauseAlignment(64, 0);
     if (const Expr *AlignmentExpr = Clause->getAlignment()) {
       auto *AlignmentCI =
           cast<llvm::ConstantInt>(CGF.EmitScalarExpr(AlignmentExpr));
-      ClauseAlignment = static_cast<unsigned>(AlignmentCI->getZExtValue());
+      ClauseAlignment = AlignmentCI->getValue();
     }
     for (const Expr *E : Clause->varlists()) {
-      unsigned Alignment = ClauseAlignment;
+      llvm::APInt Alignment(ClauseAlignment);
       if (Alignment == 0) {
         // OpenMP [2.8.1, Description]
         // If no optional parameter is specified, implementation-defined 
default
@@ -1478,12 +1478,13 @@ static void emitAlignedClause(CodeGenFunction &CGF,
                     E->getType()->getPointeeType()))
                 .getQuantity();
       }
-      assert((Alignment == 0 || llvm::isPowerOf2_32(Alignment)) &&
+      assert((Alignment == 0 || Alignment.isPowerOf2()) &&
              "alignment is not power of 2");
       if (Alignment != 0) {
         llvm::Value *PtrValue = CGF.EmitScalarExpr(E);
         CGF.EmitAlignmentAssumption(
-            PtrValue, E, /*No second loc needed*/ SourceLocation(), Alignment);
+            PtrValue, E, /*No second loc needed*/ SourceLocation(),
+            llvm::ConstantInt::get(CGF.getLLVMContext(), Alignment));
       }
     }
   }

Modified: head/contrib/llvm-project/clang/lib/CodeGen/CodeGenFunction.cpp
==============================================================================
--- head/contrib/llvm-project/clang/lib/CodeGen/CodeGenFunction.cpp     Fri Mar 
 6 16:52:20 2020        (r358710)
+++ head/contrib/llvm-project/clang/lib/CodeGen/CodeGenFunction.cpp     Fri Mar 
 6 17:02:14 2020        (r358711)
@@ -2048,24 +2048,9 @@ void CodeGenFunction::EmitAlignmentAssumption(llvm::Va
 }
 
 void CodeGenFunction::EmitAlignmentAssumption(llvm::Value *PtrValue,
-                                              QualType Ty, SourceLocation Loc,
-                                              SourceLocation AssumptionLoc,
-                                              unsigned Alignment,
-                                              llvm::Value *OffsetValue) {
-  llvm::Value *TheCheck;
-  llvm::Instruction *Assumption = Builder.CreateAlignmentAssumption(
-      CGM.getDataLayout(), PtrValue, Alignment, OffsetValue, &TheCheck);
-  if (SanOpts.has(SanitizerKind::Alignment)) {
-    llvm::Value *AlignmentVal = llvm::ConstantInt::get(IntPtrTy, Alignment);
-    EmitAlignmentAssumptionCheck(PtrValue, Ty, Loc, AssumptionLoc, 
AlignmentVal,
-                                 OffsetValue, TheCheck, Assumption);
-  }
-}
-
-void CodeGenFunction::EmitAlignmentAssumption(llvm::Value *PtrValue,
                                               const Expr *E,
                                               SourceLocation AssumptionLoc,
-                                              unsigned Alignment,
+                                              llvm::Value *Alignment,
                                               llvm::Value *OffsetValue) {
   if (auto *CE = dyn_cast<CastExpr>(E))
     E = CE->getSubExprAsWritten();

Modified: head/contrib/llvm-project/clang/lib/CodeGen/CodeGenFunction.h
==============================================================================
--- head/contrib/llvm-project/clang/lib/CodeGen/CodeGenFunction.h       Fri Mar 
 6 16:52:20 2020        (r358710)
+++ head/contrib/llvm-project/clang/lib/CodeGen/CodeGenFunction.h       Fri Mar 
 6 17:02:14 2020        (r358711)
@@ -2829,13 +2829,8 @@ class CodeGenFunction : public CodeGenTypeCache { (pub
                                llvm::Value *Alignment,
                                llvm::Value *OffsetValue = nullptr);
 
-  void EmitAlignmentAssumption(llvm::Value *PtrValue, QualType Ty,
-                               SourceLocation Loc, SourceLocation 
AssumptionLoc,
-                               unsigned Alignment,
-                               llvm::Value *OffsetValue = nullptr);
-
   void EmitAlignmentAssumption(llvm::Value *PtrValue, const Expr *E,
-                               SourceLocation AssumptionLoc, unsigned 
Alignment,
+                               SourceLocation AssumptionLoc, llvm::Value 
*Alignment,
                                llvm::Value *OffsetValue = nullptr);
 
   
//===--------------------------------------------------------------------===//

Modified: head/contrib/llvm-project/clang/lib/Sema/SemaChecking.cpp
==============================================================================
--- head/contrib/llvm-project/clang/lib/Sema/SemaChecking.cpp   Fri Mar  6 
16:52:20 2020        (r358710)
+++ head/contrib/llvm-project/clang/lib/Sema/SemaChecking.cpp   Fri Mar  6 
17:02:14 2020        (r358711)
@@ -5961,6 +5961,12 @@ bool Sema::SemaBuiltinAssumeAligned(CallExpr *TheCall)
     if (!Result.isPowerOf2())
       return Diag(TheCall->getBeginLoc(), diag::err_alignment_not_power_of_two)
              << Arg->getSourceRange();
+
+    // Alignment calculations can wrap around if it's greater than 2**29.
+    unsigned MaximumAlignment = 536870912;
+    if (Result > MaximumAlignment)
+      Diag(TheCall->getBeginLoc(), diag::warn_assume_aligned_too_great)
+          << Arg->getSourceRange() << MaximumAlignment;
   }
 
   if (NumArgs > 2) {
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