Commit b45efad4 authored by Tom Stellard's avatar Tom Stellard
Browse files

Merging r313398: 

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r313398 | steven_wu | 2017-09-15 14:12:14 -0700 (Fri, 15 Sep 2017) | 19 lines

[AutoUpgrade] Fix a compatibility issue with module flag

Summary:
After r304661, module flag to record objective-c image info section is
encoded without whitespaces after comma. The new name is equivalent to
the old one, except that when LTO a module built by old compiler and a
module built by a new compiler, it will fail with conflicting values.

Fix the issue by removing whitespaces in bitcode upgrade path.

rdar://problem/34416934

Reviewers: compnerd

Reviewed By: compnerd

Subscribers: mehdi_amini, hans, llvm-commits

Differential Revision: https://reviews.llvm.org/D37909
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llvm-svn: 318850
parent f0cacaaa

llvm/lib/IR/AutoUpgrade.cpp

+18 −0
Original line number Diff line number Diff line
@@ -2271,6 +2271,24 @@ bool llvm::UpgradeModuleFlags(Module &M) { 
        }

      }

    }

    // Upgrade Objective-C Image Info Section. Removed the whitespce in the

    // section name so that llvm-lto will not complain about mismatching

    // module flags that is functionally the same.

    if (ID->getString() == "Objective-C Image Info Section") {

      if (auto *Value = dyn_cast_or_null<MDString>(Op->getOperand(2))) {

        SmallVector<StringRef, 4> ValueComp;

        Value->getString().split(ValueComp, " ");

        if (ValueComp.size() != 1) {

          std::string NewValue;

          for (auto &S : ValueComp)

            NewValue += S.str();

          Metadata *Ops[3] = {Op->getOperand(0), Op->getOperand(1),

                              MDString::get(M.getContext(), NewValue)};

          ModFlags->setOperand(I, MDNode::get(M.getContext(), Ops));

          Changed = true;

        }

      }

    }

  }



  // "Objective-C Class Properties" is recently added for Objective-C. We

llvm/test/Bitcode/upgrade-module-flag.ll

+4 −2
Original line number Diff line number Diff line 
; RUN: llvm-as < %s | llvm-dis | FileCheck %s

; RUN: verify-uselistorder < %s



!llvm.module.flags = !{!0, !1, !2}

!llvm.module.flags = !{!0, !1, !2, !3}



!0 = !{i32 1, !"PIC Level", i32 1}

!1 = !{i32 1, !"PIE Level", i32 1}

!2 = !{i32 1, !"Objective-C Image Info Version", i32 0}

!3 = !{i32 1, !"Objective-C Image Info Section", !"__DATA, __objc_imageinfo, regular, no_dead_strip"}



; CHECK: !0 = !{i32 7, !"PIC Level", i32 1}

; CHECK: !1 = !{i32 7, !"PIE Level", i32 1}

; CHECK: !2 = !{i32 1, !"Objective-C Image Info Version", i32 0}

; CHECK: !3 = !{i32 4, !"Objective-C Class Properties", i32 0}
 
; CHECK: !3 = !{i32 1, !"Objective-C Image Info Section", !"__DATA,__objc_imageinfo,regular,no_dead_strip"}

; CHECK: !4 = !{i32 4, !"Objective-C Class Properties", i32 0}