Relands #149701 which was reverted in https://github.com/llvm/llvm-project/commit/185ae5cdc695248b58ae017508cc764c19bee5b7 because it broke demangling of Itanium symbols on i386. The last commit in this PR adds the fix for this (discussed in #160930). On x86 environments, the prefix of `__cdecl` functions will now be removed to match DWARF. I opened #161676 to discuss this for the other calling conventions.
This reverts commit e98f34eb08b2bf7aed787e7f8a7cea9111f044c8. This broke demangling of Itanium symbols on i386.
Before, functions created using the NativePDB plugin would not know about their mangled name. This showed when printing a stacktrace. There, only the function name was shown. For https://github.com/llvm/llvm-project/issues/143149, the mangled function name is required to separate different parts. This PR adds that name if available. The Clang AST nodes also take in a mangled name, which was previously unset. I don't think this unblocks anything further, because Clang can mangle the function anyway.
This patch causes the various AST dump commands (`target modules dump ast`/`target dump typesystem`) to be color-highlighted. I added a `bool show_color` parameter to `SymbolFile::DumpClangAST` and `TypeSystem::Dump`. In `TypeSystemClang` I temporarily sets the `getShowColors` flag on the owned Clang AST (using an RAII helper) for the duration of the AST dump. We use `Debugger::GetUseColors` to decide whether to color the AST dump.
This is a major change on how we represent nested name qualifications in the AST. * The nested name specifier itself and how it's stored is changed. The prefixes for types are handled within the type hierarchy, which makes canonicalization for them super cheap, no memory allocation required. Also translating a type into nested name specifier form becomes a no-op. An identifier is stored as a DependentNameType. The nested name specifier gains a lightweight handle class, to be used instead of passing around pointers, which is similar to what is implemented for TemplateName. There is still one free bit available, and this handle can be used within a PointerUnion and PointerIntPair, which should keep bit-packing aficionados happy. * The ElaboratedType node is removed, all type nodes in which it could previously apply to can now store the elaborated keyword and name qualifier, tail allocating when present. * TagTypes can now point to the exact declaration found when producing these, as opposed to the previous situation of there only existing one TagType per entity. This increases the amount of type sugar retained, and can have several applications, for example in tracking module ownership, and other tools which care about source file origins, such as IWYU. These TagTypes are lazily allocated, in order to limit the increase in AST size. This patch offers a great performance benefit. It greatly improves compilation time for [stdexec](https://github.com/NVIDIA/stdexec). For one datapoint, for `test_on2.cpp` in that project, which is the slowest compiling test, this patch improves `-c` compilation time by about 7.2%, with the `-fsyntax-only` improvement being at ~12%. This has great results on compile-time-tracker as well:  This patch also further enables other optimziations in the future, and will reduce the performance impact of template specialization resugaring when that lands. It has some other miscelaneous drive-by fixes. About the review: Yes the patch is huge, sorry about that. Part of the reason is that I started by the nested name specifier part, before the ElaboratedType part, but that had a huge performance downside, as ElaboratedType is a big performance hog. I didn't have the steam to go back and change the patch after the fact. There is also a lot of internal API changes, and it made sense to remove ElaboratedType in one go, versus removing it from one type at a time, as that would present much more churn to the users. Also, the nested name specifier having a different API avoids missing changes related to how prefixes work now, which could make existing code compile but not work. How to review: The important changes are all in `clang/include/clang/AST` and `clang/lib/AST`, with also important changes in `clang/lib/Sema/TreeTransform.h`. The rest and bulk of the changes are mostly consequences of the changes in API. PS: TagType::getDecl is renamed to `getOriginalDecl` in this patch, just for easier to rebasing. I plan to rename it back after this lands. Fixes #136624 Fixes https://github.com/llvm/llvm-project/issues/43179 Fixes https://github.com/llvm/llvm-project/issues/68670 Fixes https://github.com/llvm/llvm-project/issues/92757
Languages other than C/C++ don't necessarily emit mangled names in the
`UniqueName` field of type records. Rust specifically emits a unique ID
that doesn't contain the name.
For example, `(i32, i32)` is emitted as
```llvm
!266 = !DICompositeType(
tag: DW_TAG_structure_type, name: "tuple$<i32,i32>", file: !9, size: 64, align: 32,
elements: !267, templateParams: !17, identifier: "19122721b0632fe96c0dd37477674472"
)
```
which results in
```
0x1091 | LF_STRUCTURE [size = 72, hash = 0x1AC67] `tuple$<i32,i32>`
unique name: `19122721b0632fe96c0dd37477674472`
vtable: <no type>, base list: <no type>, field list: 0x1090
options: has unique name, sizeof 8
```
In C++ with Clang and MSVC, a structure similar to this would result in
```
0x136F | LF_STRUCTURE [size = 44, hash = 0x30BE2] `MyTuple`
unique name: `.?AUMyTuple@@`
vtable: <no type>, base list: <no type>, field list: 0x136E
options: has unique name, sizeof 8
```
With this PR, if a `UniqueName` is encountered that couldn't be parsed,
it will fall back to using the undecorated (→ do the same as if the
unique name is empty/unavailable).
I'm not sure how to test this. Maybe compiling the LLVM IR that rustc
emits?
Fixes #152051.
`FindNamespace` was not implemented for `SymbolFileNativePDB`. Without it, it wasn't possible to lookup items through namespaces when evaluating expressions. This is mostly the same as in [SymbolFilePDB](https://github.com/llvm/llvm-project/blob/f1eb869bae2ab86726ee3a5a5c7980d5b2acbd5d/lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp#L1664-L1696) as well as [PDBAstParser](https://github.com/llvm/llvm-project/blob/f1eb869bae2ab86726ee3a5a5c7980d5b2acbd5d/lldb/source/Plugins/SymbolFile/PDB/PDBASTParser.cpp#L1126-L1150): The AST parser/builder saves the created namespaces in a map to lookup when a namespace is requested. This is working towards making [Shell/SymbolFile/PDB/expressions.test](https://github.com/llvm/llvm-project/blob/f1eb869bae2ab86726ee3a5a5c7980d5b2acbd5d/lldb/test/Shell/SymbolFile/PDB/expressions.test) pass with the native PDB plugin.
Split out from https://github.com/llvm/llvm-project/pull/148877 This patch prepares `TypeSystemClang` APIs to take `AsmLabel`s which concatenated strings (hence `std::string`) instead of a plain `const char*`.