(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.
Reverts llvm/llvm-project#138972
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.
The IR now includes a global variable for the debugger that holds the address of the vtable. Now every class that contains virtual functions, has a static member (marked as artificial) that identifies where that vtable is loaded in memory. The unmangled name is '_vtable$'. This new symbol will allow a debugger to easily associate classes with the physical location of their VTables using only the DWARF information. Previously, this had to be done by searching for ELF symbols with matching names; something that was time-consuming and error-prone in certain edge cases.
Rename function to meet the coding guidelines.
Use GetAddrOfGlobal, which is a more general API that takes a GlobalDecl, and handles declaring C++ destructors and other types in a general way. We can use this to generalize over functions and variable declarations. This fixes issues reported on #130674 by @lexi-nadia .
A function declared with the `sycl_kernel_entry_point` attribute, sometimes called a SYCL kernel entry point function, specifies a pattern from which the parameters and body of an offload entry point function, sometimes called a SYCL kernel caller function, are derived. SYCL kernel caller functions are emitted during SYCL device compilation. Their parameters and body are derived from the `SYCLKernelCallStmt` statement and `OutlinedFunctionDecl` declaration associated with their corresponding SYCL kernel entry point function. A distinct SYCL kernel caller function is generated for each SYCL kernel entry point function defined as a non-inline function or ODR-used in the translation unit. The name of each SYCL kernel caller function is parameterized by the SYCL kernel name type specified by the `sycl_kernel_entry_point` attribute attached to the corresponding SYCL kernel entry point function. For the moment, the Itanium ABI mangled name for typeinfo data (`_ZTS<type>`) is used to name these functions; a future change will switch to a more appropriate naming scheme. The calling convention used for a SYCL kernel caller function is target dependent. Support for AMDGCN, NVPTX, and SPIR targets is currently provided. These functions are required to observe the language restrictions for SYCL devices as specified by the SYCL 2020 specification; this includes a forward progress guarantee and prohibits recursion. Only SYCL kernel caller functions, functions declared as `SYCL_EXTERNAL`, and functions directly or indirectly referenced from those functions should be emitted during device compilation. Pruning of other declarations has not yet been implemented. --------- Co-authored-by: Elizabeth Andrews <elizabeth.andrews@intel.com>
Finding operator delete[] is still problematic, without it the extension is a security hazard, so reverting until the problem with operator delete[] is figured out. This reverts the following PRs: Reland [MS][clang] Add support for vector deleting destructors (llvm#133451) [MS][clang] Make sure vector deleting dtor calls correct operator delete (llvm#133950) [MS][clang] Fix crash on deletion of array of pointers (llvm#134088) [clang] Do not diagnose unused deleted operator delete[] (llvm#134357) [MS][clang] Error about ambiguous operator delete[] only when required (llvm#135041)
Whereas it is UB in terms of the standard to delete an array of objects via pointer whose static type doesn't match its dynamic type, MSVC supports an extension allowing to do it. Aside from array deletion not working correctly in the mentioned case, currently not having this extension implemented causes clang to generate code that is not compatible with the code generated by MSVC, because clang always puts scalar deleting destructor to the vftable. This PR aims to resolve these problems. It was reverted due to link time errors in chromium with sanitizer coverage enabled, which is fixed by https://github.com/llvm/llvm-project/pull/131929 . The second commit of this PR also contains a fix for a runtime failure in chromium reported in https://github.com/llvm/llvm-project/pull/126240#issuecomment-2730216384 . Fixes https://github.com/llvm/llvm-project/issues/19772
I'm adding support for SPIR-V, so let's consolidate these checks. --------- Signed-off-by: Sarnie, Nick <nick.sarnie@intel.com>