[all-commits] [llvm/llvm-project] 066eea: Revert "Reland "clang][DebugInfo] Emit global vari...

[Hans via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 066eea75d38957353824b46474413ef2632d01a7
      https://github.com/llvm/llvm-project/commit/066eea75d38957353824b46474413ef2632d01a7
  Author: Hans Wennborg <hans at chromium.org>
  Date:   2023-11-07 (Tue, 07 Nov 2023)

  Changed paths:
    M clang/lib/CodeGen/CGDebugInfo.cpp
    M clang/lib/CodeGen/CGDebugInfo.h
    M clang/test/CodeGenCXX/debug-info-class.cpp
    R clang/test/CodeGenCXX/debug-info-static-inline-member.cpp
    M clang/test/CodeGenCXX/debug-info-static-member.cpp
    M lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
    M lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h
    M lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h
    M lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp
    M lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.h
    M lldb/test/API/lang/cpp/const_static_integral_member/TestConstStaticIntegralMember.py
    M lldb/test/API/lang/cpp/const_static_integral_member/main.cpp
    M lldb/test/API/tools/lldb-dap/variables/TestDAP_variables.py

  Log Message:
  -----------
  Revert "Reland "clang][DebugInfo] Emit global variable definitions for static data members with constant initializers (#70639)""

This casued asserts:

  llvm/lib/IR/Metadata.cpp:689:
  void llvm::MDNode::resolve(): Assertion `isUniqued() && "Expected this to be uniqued"' failed.

See comments on the PR.

This also reverts the dependent follow-up commits, see below.

> When an LLDB user asks for the value of a static data member, LLDB
> starts by searching the Names accelerator table for the corresponding
> variable definition DIE. For static data members with out-of-class
> definitions that works fine, because those get represented as global
> variables with a location and making them eligible to be added to the
> Names table. However, in-class definitions won<E2><80><99>t get indexed because
> we usually don't emit global variables for them. So in DWARF we end
> up with a single `DW_TAG_member` that usually holds the constant
> initializer.  But we don't get a corresponding CU-level
> `DW_TAG_variable` like we do for out-of-class definitions.
>
> To make it more convenient for debuggers to get to the value of
> inline static data members, this patch makes sure we emit definitions
> for static variables with constant initializers the same way we do
> for other static variables. This also aligns Clang closer to GCC,
> which produces CU-level definitions for inline statics and also
> emits these into `.debug_pubnames`.
>
> The implementation keeps track of newly created static data members.
> Then in `CGDebugInfo::finalize`, we emit a global `DW_TAG_variable`
> with a `DW_AT_const_value` for any of those declarations that didn't
> end up with a definition in the `DeclCache`.
>
> The newly emitted `DW_TAG_variable` will look as follows:
> ```
> 0x0000007b:   DW_TAG_structure_type
>                 DW_AT_calling_convention        (DW_CC_pass_by_value)
>                 DW_AT_name      ("Foo")
>                 ...
>
> 0x0000008d:     DW_TAG_member
>                   DW_AT_name    ("i")
>                   DW_AT_type    (0x00000062 "const int")
>                   DW_AT_external        (true)
>                   DW_AT_declaration     (true)
>                   DW_AT_const_value     (4)
>
> Newly added
> vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
>
> 0x0000009a:   DW_TAG_variable
>                 DW_AT_specification     (0x0000008d "i")
>                 DW_AT_const_value       (4)
>                 DW_AT_linkage_name      ("_ZN2t2IiE1iIfEE")
> ```
>
> This patch also drops the `DW_AT_const_value` off of the declaration
> since we now always have it on the definition. This ensures that the
> `DWARFParallelLinker` can type-merge class with static members where
> we couldn't attach the constant on the declaration in some CUs.

This reverts commit 7c3707aea8a6f1fc245ad2862982b8a51b6c0fea.
This reverts commit cab0a19467ac2e6e1e022087f4b6cb90d55da040.
This reverts commit 317481b3c8b34b0c3f106c514e6aa39b70886110.
This reverts commit 15fc809404d4715822e5349b76dcca50eb100eec.
This reverts commit 470de2bbec7f5fdd199775aa99c68ac76f4d5c74.