Christian Weisgerber <[email protected]> wrote:
> Mark Kettenis:
>
> > CVSROOT: /cvs
> > Module name: src
> > Changes by: [email protected] 2023/04/17 12:10:26
> >
> > Modified files:
> > gnu/llvm/clang/lib/Driver/ToolChains: Clang.cpp
> >
> > Log message:
> > Make -mbranch-protection=bti the default on OpenBSD.
>
> LLVM 15 reshuffled some code, so the change above no longer applies
> there. Here's my attempt to add it:
I suspect there will be a different arm64 variation of that diff coming
which tries to change the default at a lower level.
Here is the corresponding amd64 diff (an earlier version had a bug) for
in-tree clang. It changes it so BTI is enabled by default, and then adds
missing code to allow it to be turned off.
Index: gnu/llvm/clang/include/clang/Basic/CodeGenOptions.def
===================================================================
RCS file: /cvs/src/gnu/llvm/clang/include/clang/Basic/CodeGenOptions.def,v
retrieving revision 1.4
diff -u -p -u -r1.4 CodeGenOptions.def
--- gnu/llvm/clang/include/clang/Basic/CodeGenOptions.def 17 Dec 2021
14:46:43 -0000 1.4
+++ gnu/llvm/clang/include/clang/Basic/CodeGenOptions.def 17 Apr 2023
18:36:15 -0000
@@ -102,7 +102,7 @@ CODEGENOPT(InstrumentFunctionEntryBare ,
///< -finstrument-function-entry-bare is
enabled.
CODEGENOPT(CFProtectionReturn , 1, 0) ///< if -fcf-protection is
///< set to full or return.
-CODEGENOPT(CFProtectionBranch , 1, 0) ///< if -fcf-protection is
+CODEGENOPT(CFProtectionBranch , 1, 1) ///< if -fcf-protection is
///< set to full or branch.
CODEGENOPT(XRayInstrumentFunctions , 1, 0) ///< Set when -fxray-instrument is
///< enabled.
Index: gnu/llvm/clang/lib/Frontend/CompilerInvocation.cpp
===================================================================
RCS file: /cvs/src/gnu/llvm/clang/lib/Frontend/CompilerInvocation.cpp,v
retrieving revision 1.5
diff -u -p -u -r1.5 CompilerInvocation.cpp
--- gnu/llvm/clang/lib/Frontend/CompilerInvocation.cpp 17 Dec 2021 14:46:44
-0000 1.5
+++ gnu/llvm/clang/lib/Frontend/CompilerInvocation.cpp 18 Apr 2023 10:48:28
-0000
@@ -1792,7 +1792,10 @@ bool CompilerInvocation::ParseCodeGenArg
Opts.CFProtectionReturn = 1;
else if (Name == "branch")
Opts.CFProtectionBranch = 1;
- else if (Name != "none")
+ else if (Name == "none") {
+ Opts.CFProtectionBranch = 0;
+ Opts.CFProtectionReturn = 0;
+ } else
Diags.Report(diag::err_drv_invalid_value) << A->getAsString(Args) <<
Name;
}
@@ -3653,7 +3656,8 @@ bool CompilerInvocation::ParseLangArgs(L
StringRef Name = A->getValue();
if (Name == "full" || Name == "branch") {
Opts.CFProtectionBranch = 1;
- }
+ } else if (Name == "none")
+ Opts.CFProtectionBranch = 1;
}
if ((Args.hasArg(OPT_fsycl_is_device) || Args.hasArg(OPT_fsycl_is_host)) &&
