(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.
We should abstract this logic away to `TargetInfo`. See https://github.com/llvm/llvm-project/pull/137882 for more information. --------- Signed-off-by: Sarnie, Nick <nick.sarnie@intel.com>
We don't need lambdas here.
This extends https://github.com/llvm/llvm-project/pull/138577 to more UBSan checks, by changing SanitizerDebugLocation (formerly SanitizerScope) to add annotations if enabled for the specified ordinals. Annotations will use the ordinal name if there is exactly one ordinal specified in the SanitizerDebugLocation; otherwise, it will use the handler name. Updates the tests from https://github.com/llvm/llvm-project/pull/141814. --------- Co-authored-by: Vitaly Buka <vitalybuka@google.com>
We have multiple different attributes in clang representing device kernels for specific targets/languages. Refactor them into one attribute with different spellings to make it more easily scalable for new languages/targets. --------- Signed-off-by: Sarnie, Nick <nick.sarnie@intel.com>
This patch is part of a stack that teaches Clang to generate Key Instructions metadata for C and C++. When returning a value, stores to the `retval` allocas and branches to `return` block are put in the same atom group. They are both rank 1, which could in theory introduce an extra step in some optimized code. This low risk currently feels an acceptable for keeping the code a bit simpler (as opposed to adding scaffolding to make the store rank 2). In the case of a single return (no control flow) the return instruction inherits the atom group of the branch to the return block when the blocks get folded togather. RFC: https://discourse.llvm.org/t/rfc-improving-is-stmt-placement-for-better-interactive-debugging/82668 The feature is only functional in LLVM if LLVM is built with CMake flag LLVM_EXPERIMENTAL_KEY_INSTRUCTIONs. Eventually that flag will be removed.
[KeyInstr][Clang] Coerced store atoms This patch is part of a stack that teaches Clang to generate Key Instructions metadata for C and C++. RFC: https://discourse.llvm.org/t/rfc-improving-is-stmt-placement-for-better-interactive-debugging/82668 The feature is only functional in LLVM if LLVM is built with CMake flag LLVM_EXPERIMENTAL_KEY_INSTRUCTIONs. Eventually that flag will be removed.
The InstrProf headers are very expensive. Avoid including them in all of CodeGen/ by moving the CodeGenPGO member behind a unqiue_ptr. This reduces clang build time by 0.8%.