Revert Refactor constant evaluation of typeid(T) to track a symbolic type_info object rather than tracking the originating expression.

This reverts r360974 (git commit 7ee4307b)

llvm-svn: 360988

Revert [c++20] P1327R1: Support for typeid applied to objects of polymorphic class type in constant evaluation.

This reverts r360977 (git commit f51dc8d2)

llvm-svn: 360987

Replace the member variable Target with Triple
Use Triple instead of TheTarget.getName() to dispatch on 32-bit/64-bit.
Delete redundant parameters

llvm-svn: 360986

Summary:
This patch adds a libClang_shared library on *nix systems which exports the entire C++ API. In order to support this on Windows we should really refactor llvm-shlib and share code between the two.

This also uses a slightly different method for generating the shared library, which I should back-port to llvm-shlib. Instead of linking the static archives and passing linker flags to force loading the whole libraries, this patch creates object libraries for every library (which has no cost in the build system), and link the object libraries.

llvm-svn: 360985

This patch implements a limited form of autolinking primarily designed to allow
either the --dependent-library compiler option, or "comment lib" pragmas (
https://docs.microsoft.com/en-us/cpp/preprocessor/comment-c-cpp?view=vs-2017) in
C/C++ e.g. #pragma comment(lib, "foo"), to cause an ELF linker to automatically
add the specified library to the link when processing the input file generated
by the compiler.

Currently this extension is unique to LLVM and LLD. However, care has been taken
to design this feature so that it could be supported by other ELF linkers.

The design goals were to provide:

- A simple linking model for developers to reason about.
- The ability to to override autolinking from the linker command line.
- Source code compatibility, where possible, with "comment lib" pragmas in other
  environments (MSVC in particular).

Dependent library support is implemented differently for ELF platforms than on
the other platforms. Primarily this difference is that on ELF we pass the
dependent library specifiers directly to the linker without manipulating them.
This is in contrast to other platforms where they are mapped to a specific
linker option by the compiler. This difference is a result of the greater
variety of ELF linkers and the fact that ELF linkers tend to handle libraries in
a more complicated fashion than on other platforms. This forces us to defer
handling the specifiers to the linker.

In order to achieve a level of source code compatibility with other platforms
we have restricted this feature to work with libraries that meet the following
"reasonable" requirements:

1. There are no competing defined symbols in a given set of libraries, or
   if they exist, the program owner doesn't care which is linked to their
   program.
2. There may be circular dependencies between libraries.

The binary representation is a mergeable string section (SHF_MERGE,
SHF_STRINGS), called .deplibs, with custom type SHT_LLVM_DEPENDENT_LIBRARIES
(0x6fff4c04). The compiler forms this section by concatenating the arguments of
the "comment lib" pragmas and --dependent-library options in the order they are
encountered. Partial (-r, -Ur) links are handled by concatenating .deplibs
sections with the normal mergeable string section rules. As an example, #pragma
comment(lib, "foo") would result in:

.section ".deplibs","MS",@llvm_dependent_libraries,1
         .asciz "foo"

For LTO, equivalent information to the contents of a the .deplibs section can be
retrieved by the LLD for bitcode input files.

LLD processes the dependent library specifiers in the following way:

1. Dependent libraries which are found from the specifiers in .deplibs sections
   of relocatable object files are added when the linker decides to include that
   file (which could itself be in a library) in the link. Dependent libraries
   behave as if they were appended to the command line after all other options. As
   a consequence the set of dependent libraries are searched last to resolve
   symbols.
2. It is an error if a file cannot be found for a given specifier.
3. Any command line options in effect at the end of the command line parsing apply
   to the dependent libraries, e.g. --whole-archive.
4. The linker tries to add a library or relocatable object file from each of the
   strings in a .deplibs section by; first, handling the string as if it was
   specified on the command line; second, by looking for the string in each of the
   library search paths in turn; third, by looking for a lib<string>.a or
   lib<string>.so (depending on the current mode of the linker) in each of the
   library search paths.
5. A new command line option --no-dependent-libraries tells LLD to ignore the
   dependent libraries.

Rationale for the above points:

1. Adding the dependent libraries last makes the process simple to understand
   from a developers perspective. All linkers are able to implement this scheme.
2. Error-ing for libraries that are not found seems like better behavior than
   failing the link during symbol resolution.
3. It seems useful for the user to be able to apply command line options which
   will affect all of the dependent libraries. There is a potential problem of
   surprise for developers, who might not realize that these options would apply
   to these "invisible" input files; however, despite the potential for surprise,
   this is easy for developers to reason about and gives developers the control
   that they may require.
4. This algorithm takes into account all of the different ways that ELF linkers
   find input files. The different search methods are tried by the linker in most
   obvious to least obvious order.
5. I considered adding finer grained control over which dependent libraries were
   ignored (e.g. MSVC has /nodefaultlib:<library>); however, I concluded that this
   is not necessary: if finer control is required developers can fall back to using
   the command line directly.

RFC thread: http://lists.llvm.org/pipermail/llvm-dev/2019-March/131004.html.

Differential Revision: https://reviews.llvm.org/D60274

llvm-svn: 360984

This can be used to create references among sections. When --gc-sections
is used, the referenced section will be retained if the origin section
is retained.

See R_MIPS_NONE (D13659), R_ARM_NONE (D61992), R_AARCH64_NONE (D61973) for similar changes.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D62014

llvm-svn: 360983

Summary:
Removed dependency on c++ standard library. Some supporting allocators (namely Scudo on Fuchsia, and shortly, scudo standalone) has a hard requirement of no c++stdlib.

This patch updates the build system so that we don't have any c++ stdlib dependencies. It also will conveniently fix a racy build-order bug discrepency between GWP-ASan and libc++.

Reviewers: phosek, morehouse

Reviewed By: phosek, morehouse

Subscribers: kubamracek, mgorny, cryptoad, #sanitizers, llvm-commits, beanz, smeenai, vitalybuka

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D62048

llvm-svn: 360982

Summary:
This can be used to create references among sections. When --gc-sections
is used, the referenced section will be retained if the origin section
is retained.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D61973

llvm-svn: 360981

R_ARM_NONE can be used to create references among sections. When
--gc-sections is used, the referenced section will be retained if the
origin section is retained.

Add a generic MCFixupKind FK_NONE as this kind of no-op relocation is
ubiquitous on ELF and COFF, and probably available on many other binary
formats. See D62014.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D61992

llvm-svn: 360980

llvm-svn: 360978

class type in constant evaluation.

llvm-svn: 360977

Using dominance vs a set membership check is indistinguishable from a compile time perspective, and the two queries return equivelent results.  Simplify code by using the existing function.

llvm-svn: 360976

This is the last patch of the series of patches to make it possible to
resolve symbols without asking SymbolTable to do so.

The main point of this patch is the introduction of
`elf::resolveSymbol(Symbol *Old, Symbol *New)`. That function resolves
or merges given symbols by examining symbol types and call
replaceSymbol (which memcpy's New to Old) if necessary.

With the new function, we have now separated symbol resolution from
symbol lookup. If you already have a Symbol pointer, you can directly
resolve the symbol without asking SymbolTable to do that.

Now that the nice abstraction become available, I can start working on
performance improvement of the linker. As a starter, I'm thinking of
making --{start,end}-lib faster.

--{start,end}-lib is currently unnecessarily slow because it looks up
the symbol table twice for each symbol.

 - The first hash table lookup/insertion occurs when we instantiate a
   LazyObject file to insert LazyObject symbols.

 - The second hash table lookup/insertion occurs when we create an
   ObjFile from LazyObject file. That overwrites LazyObject symbols
   with Defined symbols.

I think it is not too hard to see how we can now eliminate the second
hash table lookup. We can keep LazyObject symbols in Step 1, and then
call elf::resolveSymbol() to do Step 2.

Differential Revision: https://reviews.llvm.org/D61898

llvm-svn: 360975

object rather than tracking the originating expression.

This is groundwork for supporting polymorphic typeid expressions. (Note
that this somewhat regresses our support for DR1968, but it turns out
that that never actually worked anyway, at least in non-trivial cases.)

llvm-svn: 360974

It breaks LLVM_ENABLE_PIC=OFF builds, and it's not clear
if the object library approach doesn't impact the normal
clang binary.

llvm-svn: 360973

llvm-svn: 360972

Add the proper headings instead of using just a bold font. Also add the
local ToC.

llvm-svn: 360971

getUserCost() currently returns TCC_Free for any extend of a compare (i1)
result. It seems this is only true in a limited number of cases where for
example two compares are chained. Even in those types of cases it seems
unlikely that they are generally free, while they may be in some cases.

This patch therefore removes this special handling of cast of i1. No tests
are failing because of this.

If some target want the old behavior, it could override getUserCost().

Review: Hal Finkel, Chandler Carruth, Evgeny Astigeevich, Simon Pilgrim,
        Ulrich Weigand
https://reviews.llvm.org/D54742/new/

llvm-svn: 360970

EXPECT_EQ takes two arguments, not a single expression that evaluates to bool.

llvm-svn: 360969

I'm slowly wrapping my head around this code, and am making comment improvements where I can.

llvm-svn: 360968

This is outdated, there's a bunch of architectures missing. If we want
them to be part of this table they should be a separate row anyway.

llvm-svn: 360967

Previously "bt all    " would've failed as the regex didn't match
them.

Over the shoulder review by Jonas Devlieghere.

<rdar://problem/50824935>

llvm-svn: 360966

Make sure to not unroll a vector division/remainder (with a constant splat
divisor) after type legalization, since the scalar type may then be illegal.

Review: Ulrich Weigand
https://reviews.llvm.org/D62036

llvm-svn: 360965

Unify the padding across list items and the list header.

llvm-svn: 360964

It caused PR41917.

llvm-svn: 360963

Summary:
Rather than duplicating code between PointerUnion, PointerUnion3, and
PointerUnion4 (and missing things from the latter cases, such as some of the
DenseMap support and operator==), convert PointerUnion to a variadic template
that can be used as a union of any number of pointers.

(This doesn't support PointerUnion<> right now. Adding a special case for that
would be possible, and perhaps even useful in some situations, but it doesn't
seem worthwhile until we have a concrete use case.)

Reviewers: dblaikie

Subscribers: dexonsmith, kristina, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62027

llvm-svn: 360962

These are all of the ones involving the same data layout string.  Remainder take a bit more consideration, but at least everything can be auto-updated now.

llvm-svn: 360961

These are valid Jcc, but aren't based on the EFLAGS condition codes (Intel 64
and IA-32 Architetcures Software Developer's Manual Vol. 1, Appendix B). These
are covered in clang/test, but not llvm/test.

llvm-svn: 360960

Summary:
Adds a call to __hwasan_handle_vfork(SP) at each landingpad entry.

Reusing __hwasan_handle_vfork instead of introducing a new runtime call
in order to be ABI-compatible with old runtime library.

Reviewers: pcc

Subscribers: kubamracek, hiraditya, #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D61968

llvm-svn: 360959

llvm-svn: 360958

Newly written tests to cover the simple cases.  We don't appear to have broad coverage of this transform anywhere.

llvm-svn: 360957

llvm-svn: 360956

The change broke some scenarios where debug information is still
needed, although MarkLive cannot see it, including the
Chromium/Android build. Reverting to unbreak that build.

llvm-svn: 360955

In Intel syntax, it's not uncommon to see a "short" modifier on Jcc conditional
jumps, which indicates the offset should be a "short jump" (8-bit immediate
offset from EIP, -128 to +127). This patch expands to all recognized Jcc
condition codes, and removes the inline restriction.

Clang already ignores "jmp short" in inline assembly. However, only "jmp" and a
couple of Jcc are actually checked, and only inline (i.e., not when using the
integrated assembler for asm sources). A quick search through asm-containing
libraries at hand shows a pretty broad range of Jcc conditions spelled with
"short."

GAS ignores the "short" modifier, and instead uses an encoding based on the
given immediate. MS inline seems to do the same, and I suspect MASM does, too.
NASM will yield an error if presented with an out-of-range immediate value.

Example of GCC 9.1 and MSVC v19.20, "jmp short" with offsets that do and do not
fit within 8 bits: https://gcc.godbolt.org/z/aFZmjY

Differential Revision: https://reviews.llvm.org/D61990

llvm-svn: 360954

This better matches the verbiage in Intel documentation, and should help avoid
confusion between these two different kinds of values, both of which are parsed
from mnemonics.

llvm-svn: 360953

Summary:
This refactors four pieces of code that create SDNodes for references to
symbols:
- normal global address lowering (LEA, MOV, etc)
- callee global address lowering (CALL)
- external symbol address lowering (LEA, MOV, etc)
- external symbol address lowering (CALL)

Each of these pieces of code need to:
- classify the reference
- lower the symbol
- emit a RIP wrapper if needed
- emit a load if needed
- add offsets if needed

I think handling them all in one place will make the code easier to
maintain in the future.

Reviewers: craig.topper, RKSimon

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61690

llvm-svn: 360952

llvm-svn: 360951

Summary:
This emits S_CONSTANT records for global variables.
Currently this emits records for the global variables already being tracked in the
LLVM IR metadata, which are just constant global variables; we'll also want S_CONSTANTs
for static data members and enums.

Related to https://bugs.llvm.org/show_bug.cgi?id=41615

Reviewers: rnk

Subscribers: aprantl, hiraditya, llvm-commits, thakis

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61926

llvm-svn: 360948

llvm-svn: 360947

Summary:
This patch adds a libClang_shared library on *nix systems which exports the entire C++ API. In order to support this on Windows we should really refactor llvm-shlib and share code between the two.

This also uses a slightly different method for generating the shared library, which I should back-port to llvm-shlib. Instead of linking the static archives and passing linker flags to force loading the whole libraries, this patch creates object libraries for every library (which has no cost in the build system), and link the object libraries.

Reviewers: tstellar, winksaville

Subscribers: mgorny, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D61909

llvm-svn: 360946