On Mar 6, 2007, at 8:25 AM, Duncan Sands wrote: > This patch applies on top of the previously posted patch > "llvm-gcc: use component_ref_field_offset in component references", > http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20070226/045399.html > > . > > This fixes wrong handling of structs containing more than one > variable sized field. Two C testcases are attached. Consider > for example the struct from VarSizeInStruct1: > struct f { char w; char x[n]; char z[]; }; > DecodeStructFields does the following: it creates a field for > w; it skips x; it doesn't skip z because it is the last field, > however it thinks it starts at byte offset 0 because it starts > at the variable offset n+1, and so pops w out of the struct > and replaces it with z, leading to the LLVM struct { [0 * i8] }. > This causes an assertion failure later on in EmitLV_COMPONENT_REF. > The other testcase is similar, and leads to a different assertion > failure. > > I first prepared a minimal fix, but later noticed that the code for > handling variable sized struct fields was unnecessarily complicated > and came up with this more involved patch, which removes a bunch of > special casing. The existing code seems rather fixated on whether > TYPE_SIZE is constant or not, when what really matters is whether the > field starts at a constant offset. I simply skip over fields if and > only if they don't start at a constant offset, and let variable sized > fields be emitted and indexed like any others (no more ~0U field > indices). > I remove the special casing for ~0U field indices everywhere in favour > of the generic code, for example in EmitLV_COMPONENT_REF. The only > place where something still needs to be done is in > ConvertRecordCONSTRUCTOR, > but there too the code simplifies. > > I see no additional failures in the regression test suite or in > MultiSource with these changes.
Applied. - Devang _______________________________________________ llvm-commits mailing list llvm-commits@cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
