[all-commits] [llvm/llvm-project] 4802ed: Fix size of flexible array initializers, and re-en...

[Eli Friedman via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 4802edd1ac7a5aea8c8488b5baec221d722cbdde
      https://github.com/llvm/llvm-project/commit/4802edd1ac7a5aea8c8488b5baec221d722cbdde
  Author: Eli Friedman <efriedma at quicinc.com>
  Date:   2022-04-15 (Fri, 15 Apr 2022)

  Changed paths:
    M clang/include/clang/AST/Decl.h
    M clang/lib/AST/Decl.cpp
    M clang/lib/CodeGen/CGDecl.cpp
    M clang/lib/CodeGen/CGExprConstant.cpp
    M clang/lib/CodeGen/CodeGenModule.cpp
    M clang/test/CodeGen/flexible-array-init.c
    M clang/test/CodeGenCXX/flexible-array-init.cpp

  Log Message:
  -----------
  Fix size of flexible array initializers, and re-enable assertions.

In D123649, I got the formula for getFlexibleArrayInitChars slightly
wrong: the flexible array elements can be contained in the tail padding
of the struct.  Fix the formula to account for that.

With the fixed formula, we run into another issue: in some cases, we
were emitting extra padding for flexible arrray initializers. Fix
CGExprConstant so it uses a packed struct when necessary, to avoid this
extra padding.

Differential Revision: https://reviews.llvm.org/D123826