Skip to content

Latest commit

 

History

History
41 lines (29 loc) · 1.46 KB

DeprecatedFeatures.md

File metadata and controls

41 lines (29 loc) · 1.46 KB
Raw

Deprecated Features

Capstone needs to support features which were removed by LLVM in the past. Here we explain how to reintroduce them.

Reintroduction

To get the old features back we copy them from the old .td files and include them in the new ones.

To include removed features from previous LLVM versions do the following:

  1. Checkout the last LLVM version the feature was present.

  2. Copy all feature related definitions into a <ARCH>Deprecated.td file.

  3. Checkout the newest LLVM version again.

  4. Wrap the different definition types in include guards. For example the InstrInfo definitions could be included in:

    #ifndef INCLUDED_CAPSTONE_DEPR_INSTR
#ifdef CAPSTONE_DEPR_INSTR
#define INCLUDED_CAPSTONE_DEPR_INSTR // Ensures it is only included once

[Instruction definitions of removed feature]

#endif // INCLUDED_CAPSTONE_DEPR_INSTR
#endif // CAPSTONE_DEPR_INSTR

    Note that the order of #ifndef and #ifdef matters (otherwise you'll get an error from tblgen).

  5. Include the definitions in the current definition files with:

    #define CAPSTONE_DEPR_INSTR
include "<ARCH>Deprecated.md"

Notes

  • It is possible that you have to change some definitions slightly. Because certain classes no longer exist or were replaced (e.g.: GCCBuiltin -> ClangBuiltin).
  • Some new processors might need to have the feature flag (Has<DeprecatedFeature>) added to their UnsupportedFeatures list.