3 files changed, 20 insertions, 6 deletions

diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index 07fb6d56dd7..fcc8a3e5f64 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -1734,6 +1734,8 @@ void CodeGenModule::ConstructDefaultFnAttrList(StringRef Name, bool HasOptnone,
     FuncAttrs.addAttribute("less-precise-fpmad",
                            llvm::toStringRef(CodeGenOpts.LessPreciseFPMAD));
 
+    if (CodeGenOpts.NullPointerIsValid)
+      FuncAttrs.addAttribute("null-pointer-is-valid", "true");
     if (!CodeGenOpts.FPDenormalMode.empty())
       FuncAttrs.addAttribute("denormal-fp-math", CodeGenOpts.FPDenormalMode);
 
@@ -1867,7 +1869,8 @@ void CodeGenModule::ConstructAttributeList(
     }
     if (TargetDecl->hasAttr<RestrictAttr>())
       RetAttrs.addAttribute(llvm::Attribute::NoAlias);
-    if (TargetDecl->hasAttr<ReturnsNonNullAttr>())
+    if (TargetDecl->hasAttr<ReturnsNonNullAttr>() &&
+        !CodeGenOpts.NullPointerIsValid)
       RetAttrs.addAttribute(llvm::Attribute::NonNull);
     if (TargetDecl->hasAttr<AnyX86NoCallerSavedRegistersAttr>())
       FuncAttrs.addAttribute("no_caller_saved_registers");
@@ -1974,7 +1977,8 @@ void CodeGenModule::ConstructAttributeList(
     if (!PTy->isIncompleteType() && PTy->isConstantSizeType())
       RetAttrs.addDereferenceableAttr(getContext().getTypeSizeInChars(PTy)
                                         .getQuantity());
-    else if (getContext().getTargetAddressSpace(PTy) == 0)
+    else if (getContext().getTargetAddressSpace(PTy) == 0 &&
+             !CodeGenOpts.NullPointerIsValid)
       RetAttrs.addAttribute(llvm::Attribute::NonNull);
   }
 
@@ -2083,7 +2087,8 @@ void CodeGenModule::ConstructAttributeList(
       if (!PTy->isIncompleteType() && PTy->isConstantSizeType())
         Attrs.addDereferenceableAttr(getContext().getTypeSizeInChars(PTy)
                                        .getQuantity());
-      else if (getContext().getTargetAddressSpace(PTy) == 0)
+      else if (getContext().getTargetAddressSpace(PTy) == 0 &&
+               !CodeGenOpts.NullPointerIsValid)
         Attrs.addAttribute(llvm::Attribute::NonNull);
     }
 
@@ -2343,7 +2348,8 @@ void CodeGenFunction::EmitFunctionProlog(const CGFunctionInfo &FI,
 
         if (const ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(Arg)) {
           if (getNonNullAttr(CurCodeDecl, PVD, PVD->getType(),
-                             PVD->getFunctionScopeIndex()))
+                             PVD->getFunctionScopeIndex()) &&
+              !CGM.getCodeGenOpts().NullPointerIsValid)
             AI->addAttr(llvm::Attribute::NonNull);
 
           QualType OTy = PVD->getOriginalType();
@@ -2362,7 +2368,8 @@ void CodeGenFunction::EmitFunctionProlog(const CGFunctionInfo &FI,
                 Attrs.addDereferenceableAttr(
                   getContext().getTypeSizeInChars(ETy).getQuantity()*ArrSize);
                 AI->addAttrs(Attrs);
-              } else if (getContext().getTargetAddressSpace(ETy) == 0) {
+              } else if (getContext().getTargetAddressSpace(ETy) == 0 &&
+                         !CGM.getCodeGenOpts().NullPointerIsValid) {
                 AI->addAttr(llvm::Attribute::NonNull);
               }
             }
@@ -2372,7 +2379,8 @@ void CodeGenFunction::EmitFunctionProlog(const CGFunctionInfo &FI,
             // we can't use the dereferenceable attribute, but in addrspace(0)
             // we know that it must be nonnull.
             if (ArrTy->getSizeModifier() == VariableArrayType::Static &&
-                !getContext().getTargetAddressSpace(ArrTy->getElementType()))
+                !getContext().getTargetAddressSpace(ArrTy->getElementType()) &&
+                !CGM.getCodeGenOpts().NullPointerIsValid)
               AI->addAttr(llvm::Attribute::NonNull);
           }
 
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 4db4dc19a8b..e23ff16699f 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -3348,6 +3348,10 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
                    options::OPT_fno_merge_all_constants, false))
     CmdArgs.push_back("-fmerge-all-constants");
 
+  if (Args.hasFlag(options::OPT_fno_delete_null_pointer_checks,
+                   options::OPT_fdelete_null_pointer_checks, false))
+    CmdArgs.push_back("-fno-delete-null-pointer-checks");
+
   // LLVM Code Generator Options.
 
   if (Args.hasArg(options::OPT_frewrite_map_file) ||
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index c26d5fb79b3..9bb673d1e77 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -746,6 +746,8 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
 
   Opts.NoUseJumpTables = Args.hasArg(OPT_fno_jump_tables);
 
+  Opts.NullPointerIsValid = Args.hasArg(OPT_fno_delete_null_pointer_checks);
+
   Opts.ProfileSampleAccurate = Args.hasArg(OPT_fprofile_sample_accurate);
 
   Opts.PrepareForLTO = Args.hasArg(OPT_flto, OPT_flto_EQ);