diff options
Diffstat (limited to 'lib/Target/X86/X86.td')
| -rw-r--r-- | lib/Target/X86/X86.td | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/lib/Target/X86/X86.td b/lib/Target/X86/X86.td index ba998467b7990..ba97982e3330e 100644 --- a/lib/Target/X86/X86.td +++ b/lib/Target/X86/X86.td @@ -329,6 +329,27 @@ def FeatureHasFastGather : SubtargetFeature<"fast-gather", "HasFastGather", "true", "Indicates if gather is reasonably fast.">; +// Enable mitigation of some aspects of speculative execution related +// vulnerabilities by removing speculatable indirect branches. This disables +// jump-table formation, rewrites explicit `indirectbr` instructions into +// `switch` instructions, and uses a special construct called a "retpoline" to +// prevent speculation of the remaining indirect branches (indirect calls and +// tail calls). +def FeatureRetpoline + : SubtargetFeature<"retpoline", "UseRetpoline", "true", + "Remove speculation of indirect branches from the " + "generated code, either by avoiding them entirely or " + "lowering them with a speculation blocking construct.">; + +// Rely on external thunks for the emitted retpoline calls. This allows users +// to provide their own custom thunk definitions in highly specialized +// environments such as a kernel that does boot-time hot patching. +def FeatureRetpolineExternalThunk + : SubtargetFeature< + "retpoline-external-thunk", "UseRetpolineExternalThunk", "true", + "Enable retpoline, but with an externally provided thunk.", + [FeatureRetpoline]>; + //===----------------------------------------------------------------------===// // Register File Description //===----------------------------------------------------------------------===// |