Author: phosek Date: Tue Jun 12 13:00:50 2018 New Revision: 334531 URL: http://llvm.org/viewvc/llvm-project?rev=334531&view=rev Log: [AArch64] Support reserving x20 register
Register x20 is a callee-saved register which may be used for other purposes in certain contexts, for example to hold special variables within the kernel. This change adds support for reserving this register both to frontend and backend to make this register usable for these purposes. Differential Revision: https://reviews.llvm.org/D46552 Added: cfe/trunk/test/Driver/aarch64-fixed-x20.c Modified: cfe/trunk/docs/ClangCommandLineReference.rst cfe/trunk/include/clang/Driver/Options.td cfe/trunk/lib/Driver/ToolChains/Arch/AArch64.cpp Modified: cfe/trunk/docs/ClangCommandLineReference.rst URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/docs/ClangCommandLineReference.rst?rev=334531&r1=334530&r2=334531&view=diff ============================================================================== --- cfe/trunk/docs/ClangCommandLineReference.rst (original) +++ cfe/trunk/docs/ClangCommandLineReference.rst Tue Jun 12 13:00:50 2018 @@ -2296,6 +2296,10 @@ AARCH64 Reserve the x18 register (AArch64 only) +.. option:: -ffixed-x20 + +Reserve the x20 register (AArch64 only) + .. option:: -mfix-cortex-a53-835769, -mno-fix-cortex-a53-835769 Workaround Cortex-A53 erratum 835769 (AArch64 only) Modified: cfe/trunk/include/clang/Driver/Options.td URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Driver/Options.td?rev=334531&r1=334530&r2=334531&view=diff ============================================================================== --- cfe/trunk/include/clang/Driver/Options.td (original) +++ cfe/trunk/include/clang/Driver/Options.td Tue Jun 12 13:00:50 2018 @@ -2004,6 +2004,8 @@ def mno_fix_cortex_a53_835769 : Flag<["- HelpText<"Don't workaround Cortex-A53 erratum 835769 (AArch64 only)">; def ffixed_x18 : Flag<["-"], "ffixed-x18">, Group<m_aarch64_Features_Group>, HelpText<"Reserve the x18 register (AArch64 only)">; +def ffixed_x20 : Flag<["-"], "ffixed-x20">, Group<m_aarch64_Features_Group>, + HelpText<"Reserve the x20 register (AArch64 only)">; def msimd128 : Flag<["-"], "msimd128">, Group<m_wasm_Features_Group>; def mno_simd128 : Flag<["-"], "mno-simd128">, Group<m_wasm_Features_Group>; Modified: cfe/trunk/lib/Driver/ToolChains/Arch/AArch64.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/ToolChains/Arch/AArch64.cpp?rev=334531&r1=334530&r2=334531&view=diff ============================================================================== --- cfe/trunk/lib/Driver/ToolChains/Arch/AArch64.cpp (original) +++ cfe/trunk/lib/Driver/ToolChains/Arch/AArch64.cpp Tue Jun 12 13:00:50 2018 @@ -198,6 +198,9 @@ void aarch64::getAArch64TargetFeatures(c if (Args.hasArg(options::OPT_ffixed_x18)) Features.push_back("+reserve-x18"); + if (Args.hasArg(options::OPT_ffixed_x20)) + Features.push_back("+reserve-x20"); + if (Args.hasArg(options::OPT_mno_neg_immediates)) Features.push_back("+no-neg-immediates"); } Added: cfe/trunk/test/Driver/aarch64-fixed-x20.c URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Driver/aarch64-fixed-x20.c?rev=334531&view=auto ============================================================================== --- cfe/trunk/test/Driver/aarch64-fixed-x20.c (added) +++ cfe/trunk/test/Driver/aarch64-fixed-x20.c Tue Jun 12 13:00:50 2018 @@ -0,0 +1,4 @@ +// RUN: %clang -target aarch64-none-gnu -ffixed-x20 -### %s 2> %t +// RUN: FileCheck --check-prefix=CHECK-FIXED-X20 < %t %s + +// CHECK-FIXED-X20: "-target-feature" "+reserve-x20" _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits