[PATCH] D79733: [clang][SLH] Add __has_feature(speculative_load_hardening)

[Zola Bridges via Phabricator via cfe-commits]

zbrid created this revision.
zbrid added reviewers: craig.topper, echristo.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.
zbrid marked an inline comment as done.
zbrid added inline comments.
zbrid marked an inline comment as done.


================
Comment at: clang/lib/Driver/ToolChains/Clang.cpp:5357
 
-  if (Args.hasFlag(options::OPT_mspeculative_load_hardening, options::OPT_mno_speculative_load_hardening,
-                   false))
+  if (Args.hasFlag(options::OPT_mspeculative_load_hardening,
+                   options::OPT_mno_speculative_load_hardening, false))
----------------
This is a style fix only.


================
Comment at: clang/lib/Driver/ToolChains/Clang.cpp:5357
 
-  if (Args.hasFlag(options::OPT_mspeculative_load_hardening, options::OPT_mno_speculative_load_hardening,
-                   false))
+  if (Args.hasFlag(options::OPT_mspeculative_load_hardening,
+                   options::OPT_mno_speculative_load_hardening, false))
----------------
zbrid wrote:
> This is a style fix only.
Err, I mean the change in this line is only a style fix. The rest of the patch is the functional change.


SLH doesn't support asm goto and is unlikely to ever support it. Users of asm
goto need a way to choose whether to use asm goto or fallback to an SLH
compatible code path when SLH is enabled. This feature flag will give users
this ability.

Tested via unit test


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D79733

Files:
  clang/include/clang/Basic/Features.def
  clang/include/clang/Basic/LangOptions.def
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp


Index: clang/lib/Frontend/CompilerInvocation.cpp
===================================================================
--- clang/lib/Frontend/CompilerInvocation.cpp
+++ clang/lib/Frontend/CompilerInvocation.cpp
@@ -3372,6 +3372,8 @@
   }
 
   Opts.BranchTargetEnforcement = Args.hasArg(OPT_mbranch_target_enforce);
+  Opts.SpeculativeLoadHardeningEnabled =
+      Args.hasArg(OPT_mspeculative_load_hardening);
 }
 
 static bool isStrictlyPreprocessorAction(frontend::ActionKind Action) {
Index: clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Clang.cpp
+++ clang/lib/Driver/ToolChains/Clang.cpp
@@ -5354,8 +5354,8 @@
 
   Args.AddLastArg(CmdArgs, options::OPT_pthread);
 
-  if (Args.hasFlag(options::OPT_mspeculative_load_hardening, options::OPT_mno_speculative_load_hardening,
-                   false))
+  if (Args.hasFlag(options::OPT_mspeculative_load_hardening,
+                   options::OPT_mno_speculative_load_hardening, false))
     CmdArgs.push_back(Args.MakeArgString("-mspeculative-load-hardening"));
 
   RenderSSPOptions(TC, Args, CmdArgs, KernelOrKext);
Index: clang/include/clang/Basic/LangOptions.def
===================================================================
--- clang/include/clang/Basic/LangOptions.def
+++ clang/include/clang/Basic/LangOptions.def
@@ -366,6 +366,9 @@
              "Key used for return address signing")
 LANGOPT(BranchTargetEnforcement, 1, 0, "Branch-target enforcement enabled")
 
+BENIGN_LANGOPT(SpeculativeLoadHardeningEnabled, 1, 0,
+               "Speculative load hardening enabled")
+
 #undef LANGOPT
 #undef COMPATIBLE_LANGOPT
 #undef BENIGN_LANGOPT
Index: clang/include/clang/Basic/Features.def
===================================================================
--- clang/include/clang/Basic/Features.def
+++ clang/include/clang/Basic/Features.def
@@ -36,6 +36,7 @@
 #define EXTENSION(Name, Predicate)
 #endif
 
+FEATURE(speculative_load_hardening, LangOpts.SpeculativeLoadHardeningEnabled)
 FEATURE(address_sanitizer,
         LangOpts.Sanitize.hasOneOf(SanitizerKind::Address |
                                    SanitizerKind::KernelAddress))


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