[cfe-commits] r113154 - in /cfe/trunk: lib/CodeGen/CGObjCMac.cpp test/CodeGenObjC/ivars.m

[Argyrios Kyrtzidis]

Fariborz please review.

On Sep 6, 2010, at 1:00 PM, Argyrios Kyrtzidis wrote:

> Author: akirtzidis
> Date: Mon Sep  6 07:00:10 2010
> New Revision: 113154
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=113154&view=rev
> Log:
> LastFieldBitfield in CGObjCCommonMac::BuildAggrIvarLayout keeps bitfields or unnamed fields but later the code
> assumes that it's always a bitfield. This can lead to a crash (reported at rdar://8368320).
> 
> Modified:
>    cfe/trunk/lib/CodeGen/CGObjCMac.cpp
>    cfe/trunk/test/CodeGenObjC/ivars.m
> 
> Modified: cfe/trunk/lib/CodeGen/CGObjCMac.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGObjCMac.cpp?rev=113154&r1=113153&r2=113154&view=diff
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CGObjCMac.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CGObjCMac.cpp Mon Sep  6 07:00:10 2010
> @@ -3586,10 +3586,10 @@
>   uint64_t MaxSkippedUnionIvarSize = 0;
>   FieldDecl *MaxField = 0;
>   FieldDecl *MaxSkippedField = 0;
> -  FieldDecl *LastFieldBitfield = 0;
> +  FieldDecl *LastFieldBitfieldOrUnnamed = 0;
>   uint64_t MaxFieldOffset = 0;
>   uint64_t MaxSkippedFieldOffset = 0;
> -  uint64_t LastBitfieldOffset = 0;
> +  uint64_t LastBitfieldOrUnnamedOffset = 0;
> 
>   if (RecFields.empty())
>     return;
> @@ -3609,12 +3609,12 @@
> 
>     // Skip over unnamed or bitfields
>     if (!Field->getIdentifier() || Field->isBitField()) {
> -      LastFieldBitfield = Field;
> -      LastBitfieldOffset = FieldOffset;
> +      LastFieldBitfieldOrUnnamed = Field;
> +      LastBitfieldOrUnnamedOffset = FieldOffset;
>       continue;
>     }
> 
> -    LastFieldBitfield = 0;
> +    LastFieldBitfieldOrUnnamed = 0;
>     QualType FQT = Field->getType();
>     if (FQT->isRecordType() || FQT->isUnionType()) {
>       if (FQT->isUnionType())
> @@ -3703,16 +3703,25 @@
>     }
>   }
> 
> -  if (LastFieldBitfield) {
> -    // Last field was a bitfield. Must update skip info.
> -    Expr *BitWidth = LastFieldBitfield->getBitWidth();
> -    uint64_t BitFieldSize =
> -      BitWidth->EvaluateAsInt(CGM.getContext()).getZExtValue();
> -    GC_IVAR skivar;
> -    skivar.ivar_bytepos = BytePos + LastBitfieldOffset;
> -    skivar.ivar_size = (BitFieldSize / ByteSizeInBits)
> -      + ((BitFieldSize % ByteSizeInBits) != 0);
> -    SkipIvars.push_back(skivar);
> +  if (LastFieldBitfieldOrUnnamed) {
> +    if (LastFieldBitfieldOrUnnamed->isBitField()) {
> +      // Last field was a bitfield. Must update skip info.
> +      Expr *BitWidth = LastFieldBitfieldOrUnnamed->getBitWidth();
> +      uint64_t BitFieldSize =
> +        BitWidth->EvaluateAsInt(CGM.getContext()).getZExtValue();
> +      GC_IVAR skivar;
> +      skivar.ivar_bytepos = BytePos + LastBitfieldOrUnnamedOffset;
> +      skivar.ivar_size = (BitFieldSize / ByteSizeInBits)
> +        + ((BitFieldSize % ByteSizeInBits) != 0);
> +      SkipIvars.push_back(skivar);
> +    } else {
> +      assert(!LastFieldBitfieldOrUnnamed->getIdentifier() &&"Expected unnamed");
> +      // Last field was unnamed. Must update skip info.
> +      unsigned FieldSize
> +          = CGM.getContext().getTypeSize(LastFieldBitfieldOrUnnamed->getType());
> +      SkipIvars.push_back(GC_IVAR(BytePos + LastBitfieldOrUnnamedOffset,
> +                                  FieldSize / ByteSizeInBits));
> +    }
>   }
> 
>   if (MaxField)
> 
> Modified: cfe/trunk/test/CodeGenObjC/ivars.m
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenObjC/ivars.m?rev=113154&r1=113153&r2=113154&view=diff
> ==============================================================================
> --- cfe/trunk/test/CodeGenObjC/ivars.m (original)
> +++ cfe/trunk/test/CodeGenObjC/ivars.m Mon Sep  6 07:00:10 2010
> @@ -1,5 +1,6 @@
> // RUN: %clang_cc1 -triple x86_64-apple-darwin9 -emit-llvm -o - %s
> // RUN: %clang_cc1 -triple i386-apple-darwin9 -emit-llvm -o - %s
> +// RUN: %clang_cc1 -fobjc-gc -emit-llvm -o - %s
> 
> // rdar://6800926
> @interface ITF {
> @@ -12,3 +13,17 @@
> void foo(ITF *P) {
>   P->boolfield = 1;
> }
> +
> +// rdar://8368320
> + at interface R {
> +  struct {
> +    union {
> +      int x;
> +      char c;
> +    };
> +  } _union;
> +}
> + at end
> +
> + at implementation R
> + at end
> 
> 
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