(This is a re-do of #138972, which had a minor warning in `Clang.cpp`.)
This PR adds some of the support needed for Windows hot-patching.
Windows implements a form of hot-patching. This allows patches to be
applied to Windows apps, drivers, and the kernel, without rebooting or
restarting any of these components. Hot-patching is a complex technology
and requires coordination between the OS, compilers, linkers, and
additional tools.
This PR adds support to Clang and LLVM for part of the hot-patching
process. It enables LLVM to generate the required code changes and to
generate CodeView symbols which identify hot-patched functions. The PR
provides new command-line arguments to Clang which allow developers to
identify the list of functions that need to be hot-patched. This PR also
allows LLVM to directly receive the list of functions to be modified, so
that language front-ends which have not yet been modified (such as Rust)
can still make use of hot-patching.
This PR:
* Adds a `MarkedForWindowsHotPatching` LLVM function attribute. This
attribute indicates that a function should be _hot-patched_. This
generates a new CodeView symbol, `S_HOTPATCHFUNC`, which identifies any
function that has been hot-patched. This attribute also causes accesses
to global variables to be indirected through a `_ref_*` global variable.
This allows hot-patched functions to access the correct version of a
global variable; the hot-patched code needs to access the variable in
the _original_ image, not the patch image.
* Adds a `AllowDirectAccessInHotPatchFunction` LLVM attribute. This
attribute may be placed on global variable declarations. It indicates
that the variable may be safely accessed without the `_ref_*`
indirection.
* Adds two Clang command-line parameters: `-fms-hotpatch-functions-file`
and `-fms-hotpatch-functions-list`. The `-file` flag may point to a text
file, which contains a list of functions to be hot-patched (one function
name per line). The `-list` flag simply directly identifies functions to
be patched, using a comma-separated list. These two command-line
parameters may also be combined; the final set of functions to be
hot-patched is the union of the two sets.
* Adds similar LLVM command-line parameters:
`--ms-hotpatch-functions-file` and `--ms-hotpatch-functions-list`.
* Adds integration tests for both LLVM and Clang.
* Adds support for dumping the new `S_HOTPATCHFUNC` CodeView symbol.
Although the flags are redundant between Clang and LLVM, this allows
additional languages (such as Rust) to take advantage of hot-patching
support before they have been modified to generate the required
attributes.
Credit to @dpaoliello, who wrote the original form of this patch.
This PR adds some of the support needed for Windows hot-patching.
Windows implements a form of hot-patching. This allows patches to be
applied to Windows apps, drivers, and the kernel, without rebooting or
restarting any of these components. Hot-patching is a complex technology
and requires coordination between the OS, compilers, linkers, and
additional tools.
This PR adds support to Clang and LLVM for part of the hot-patching
process. It enables LLVM to generate the required code changes and to
generate CodeView symbols which identify hot-patched functions. The PR
provides new command-line arguments to Clang which allow developers to
identify the list of functions that need to be hot-patched. This PR also
allows LLVM to directly receive the list of functions to be modified, so
that language front-ends which have not yet been modified (such as Rust)
can still make use of hot-patching.
This PR:
* Adds a `MarkedForWindowsHotPatching` LLVM function attribute. This
attribute indicates that a function should be _hot-patched_. This
generates a new CodeView symbol, `S_HOTPATCHFUNC`, which identifies any
function that has been hot-patched. This attribute also causes accesses
to global variables to be indirected through a `_ref_*` global variable.
This allows hot-patched functions to access the correct version of a
global variable; the hot-patched code needs to access the variable in
the _original_ image, not the patch image.
* Adds a `AllowDirectAccessInHotPatchFunction` LLVM attribute. This
attribute may be placed on global variable declarations. It indicates
that the variable may be safely accessed without the `_ref_*`
indirection.
* Adds two Clang command-line parameters: `-fms-hotpatch-functions-file`
and `-fms-hotpatch-functions-list`. The `-file` flag may point to a text
file, which contains a list of functions to be hot-patched (one function
name per line). The `-list` flag simply directly identifies functions to
be patched, using a comma-separated list. These two command-line
parameters may also be combined; the final set of functions to be
hot-patched is the union of the two sets.
* Adds similar LLVM command-line parameters:
`--ms-hotpatch-functions-file` and `--ms-hotpatch-functions-list`.
* Adds integration tests for both LLVM and Clang.
* Adds support for dumping the new `S_HOTPATCHFUNC` CodeView symbol.
Although the flags are redundant between Clang and LLVM, this allows
additional languages (such as Rust) to take advantage of hot-patching
support before they have been modified to generate the required
attributes.
Credit to @dpaoliello, who wrote the original form of this patch.
This fixes a bug where parsing PDBs with usages of register enums were
asserting.
The main problem is that printing out the code view register enums are
taken care of here:
e4888a9240/llvm/lib/ObjectYAML/CodeViewYAMLSymbols.cpp (L152)
Which requires a COFF::header in the IO context for the machine type,
which we didn't have when dumping a pdb or parsing a yaml file. So, we
make a fake one with the machine type.
A few files of llvm dir had duplicate headers included. This patch
removes those redundancies.
---------
Co-authored-by: Akash Agrawal <akashag@qti.qualcomm.com>
These symbols need to be exported for llvm-pdbutil when using windows
shared library builds.
Exclude the YAML traits declared in llvm-pdbutil so there not declared
as dllimported which will causing missing symbol errors for windows
shared library builds.
This is part of the work to enable LLVM_BUILD_LLVM_DYLIB and plugins on
window.
There are some places that want to convert an Error to string, but still
retain the original Error object, for example to emit a non-fatal
warning.
This currently isn't possible, because the entire Error infra is
move-based. And what people end up doing in this case is to move the
Error... twice.
This patch introduces a toStringWithoutConsuming() function to
accommodate this use case. This also requires some infrastructure that
allows visiting Errors without consuming them.
This adds the following values to the CodeView.h enums (and updates the
various functions that use them):
* CPUType:
* Added `Unknown`
* This is not currently documented in the online documentation, but this
is present in `cvconst.h` in the latest DIA SDK (Visual Studio 2022,
17.7.6)
* `Unknown` is the CPUType that is emitted by `aliasobj.exe` in the
Compile3Sym records, and can be found in objects that link with
`oldnames.lib`

* SourceLanguage (All of these are documented at
https://learn.microsoft.com/en-us/visualstudio/debugger/debug-interface-access/cv-cfl-lang?view=vs-2022
and are present in `cvconst.h` in the latest DIA SDK (Visual Studio
2022, 17.7.6))
* Added Go
* Added AliasObj
* emitted by `aliasobj.exe` in certain records, can be found in PDBs
that link with `oldnames.lib`
* Changed Swift to the official Microsoft enumeration
* Added `OldSwift`
* The old Swift enumeration of `S` was changed to `OldSwift` to allow
pdb dumping utilities to continue to emit correct source language
information for old PDBs
### WARNING
The `Swift` change is a potentially breaking change, as the swift
compiler will now emit `0x13` for the SourceLanguage type in PDB records
instead of `S`. This could potentially break utilities that relied on
the old enum value.
* CallType
* Added Swift
* This is not currently documented in the online documentation, but this
is present in `cvconst.h` in the latest DIA SDK (Visual Studio 2022,
17.7.6)
Note that llvm::support::endianness has been renamed to
llvm::endianness while becoming an enum class as opposed to an enum.
This patch replaces llvm::support::{big,little,native} with
llvm::endianness::{big,little,native}.
The `S_INLINEES` debug symbol is used to record all the functions that
are directly inlined within the current function (nested inlining is
ignored).
This change implements support for emitting the `S_INLINEES` debug
symbol in LLVM, and cleans up how the `S_INLINEES` and `S_CALLEES` debug
symbols are dumped.
The CodeView `S_ARMSWITCHTABLE` debug symbol is used to describe the layout of a jump table, it contains the following information:
* The address of the branch instruction that uses the jump table.
* The address of the jump table.
* The "base" address that the values in the jump table are relative to.
* The type of each entry (absolute pointer, a relative integer, a relative integer that is shifted).
Together this information can be used by debuggers and binary analysis tools to understand what an jump table indirect branch is doing and where it might jump to.
Documentation for the symbol can be found in the Microsoft PDB library dumper: 0fe89a942f/cvdump/dumpsym7.cpp (L5518)
This change adds support to LLVM to emit the `S_ARMSWITCHTABLE` debug symbol as well as to dump it out (for testing purposes).
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D149367
This reverts commit 8d0c3db388143f4e058b5f513a70fd5d089d51c3.
Causes crashes, see comments in https://reviews.llvm.org/D149367.
Some follow-up fixes are also reverted:
This reverts commit 636269f4fca44693bfd787b0a37bb0328ffcc085.
This reverts commit 5966079cf4d4de0285004eef051784d0d9f7a3a6.
This reverts commit e7294dbc85d24a08c716d9babbe7f68390cf219b.
The CodeView `S_ARMSWITCHTABLE` debug symbol is used to describe the layout of a jump table, it contains the following information:
* The address of the branch instruction that uses the jump table.
* The address of the jump table.
* The "base" address that the values in the jump table are relative to.
* The type of each entry (absolute pointer, a relative integer, a relative integer that is shifted).
Together this information can be used by debuggers and binary analysis tools to understand what an jump table indirect branch is doing and where it might jump to.
Documentation for the symbol can be found in the Microsoft PDB library dumper: 0fe89a942f/cvdump/dumpsym7.cpp (L5518)
This change adds support to LLVM to emit the `S_ARMSWITCHTABLE` debug symbol as well as to dump it out (for testing purposes).
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D149367
In preparation for removing the `#include "llvm/ADT/StringExtras.h"`
from the header to source file of `llvm/Support/Error.h`, first add in
all the missing includes that were previously included transitively
through this header.
This patch adds llvm::codeview::SourceLanguage entries, DWARF translations, and PDB source file extensions in LLVM and allow LLDB's PDB parsers to recognize them correctly.
The CV_CFL_LANG enum in the Visual Studio 2022 documentation https://learn.microsoft.com/en-us/visualstudio/debugger/debug-interface-access/cv-cfl-lang defines:
```
CV_CFL_OBJC = 0x11,
CV_CFL_OBJCXX = 0x12,
```
Since the initial commit in D24317, ObjC was emitted as C language and ObjC++ as Masm.
Reviewed By: DavidSpickett
Differential Revision: https://reviews.llvm.org/D146221
This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated. The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.
This is part of an effort to migrate from llvm::Optional to
std::optional:
https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
Right now, if we want to dump symbol at specified offset, we need to use `grep`.
And it can only show surrounding symbols in layout (not in lexical scope sense).
This adds similar options to `dump` command as `llvm-dwarfdump` to allow users
to dump symbol record at specified offset and its parents or children with
spcified depth.
`--symbol-offset=` must be used with `--modi` to dump only one symbol at given
offset.
`--show-parents`/`--show-children` must be used with `--symbol-offset` to
dump all symbols that are parents/children of the symbol at given offset.
`--parent-recurse-depth`/`--children-recurse-depth` must be used with
`--show-parents`/`--show-children` to specify the max up/down depth.
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D124317