[PATCH] D143285: X86: completely refactor `X86FrameLowering::emitPrologue`

[Saleem Abdulrasool via Phabricator via llvm-commits]

compnerd created this revision.
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This function has had a long overdue need for refactoring.  The current implementation works across the matrix of:

{IP32, IP64, I64P32} x {Function,Funclet x {Managed,Unmanaged}}

This makes the code extremely brittle and difficult to follow.  Introduce the `FrameBuilder` that constructs the shared context to emit the various operations.  The builder has a number of emitters which follow the general pattern of a series of guard statements preventing the emission if the conditions do not hold.  We then perform the build.  This allows the build operation to become entirely free of control flow - we perform the operations unconditionally.  Furthermore, it allows us to split up the operations so that we no longer have a single 600-line function that emits the prologue for every configuration.

This was initially started in D104557 <https://reviews.llvm.org/D104557>.  This applies the full transformation as a single patch (though it was perform through ~42 individual commits).


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D143285

Files:
  llvm/lib/Target/X86/X86FrameLowering.cpp
  llvm/lib/Target/X86/X86FrameLowering.h

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