Author: prakhar Date: Thu Dec 15 01:59:24 2016 New Revision: 289786 URL: http://llvm.org/viewvc/llvm-project?rev=289786&view=rev Log: [ARM] Implement execute-only support in CodeGen
Summary: This implements execute-only support for ARM code generation, which prevents the compiler from generating data accesses to code sections. The following changes are involved: * Add the CodeGen option "-arm-execute-only" to the ARM code generator. * Add the clang flag "-mexecute-only" as well as the GCC-compatible alias "-mpure-code" to enable this option. * When enabled, literal pools are replaced with MOVW/MOVT instructions, with VMOV used in addition for floating-point literals. As the MOVT instruction is required, execute-only support is only available in Thumb mode for targets supporting ARMv8-M baseline or Thumb2. * Jump tables are placed in data sections when in execute-only mode. * The execute-only text section is assigned section ID 0, and is marked as unreadable with the SHF_ARM_PURECODE flag with symbol 'y'. This also overrides selection of ELF sections for globals. Reviewers: t.p.northover, rengolin Subscribers: llvm-commits, aemerson Differential Revision: https://reviews.llvm.org/D27450 Added: cfe/trunk/test/Driver/arm-execute-only.c Modified: cfe/trunk/include/clang/Basic/DiagnosticCommonKinds.td cfe/trunk/include/clang/Driver/Options.td cfe/trunk/lib/Driver/Tools.cpp Modified: cfe/trunk/include/clang/Basic/DiagnosticCommonKinds.td URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticCommonKinds.td?rev=289786&r1=289785&r2=289786&view=diff ============================================================================== --- cfe/trunk/include/clang/Basic/DiagnosticCommonKinds.td (original) +++ cfe/trunk/include/clang/Basic/DiagnosticCommonKinds.td Thu Dec 15 01:59:24 2016 @@ -190,6 +190,8 @@ def err_target_unsupported_fpmath : Erro "the '%0' unit is not supported with this instruction set">; def err_target_unsupported_unaligned : Error< "the %0 sub-architecture does not support unaligned accesses">; +def err_target_unsupported_execute_only : Error< + "execute only is not supported for the %0 sub-architecture">; def err_opt_not_valid_with_opt : Error< "option '%0' cannot be specified with '%1'">; Modified: cfe/trunk/include/clang/Driver/Options.td URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Driver/Options.td?rev=289786&r1=289785&r2=289786&view=diff ============================================================================== --- cfe/trunk/include/clang/Driver/Options.td (original) +++ cfe/trunk/include/clang/Driver/Options.td Thu Dec 15 01:59:24 2016 @@ -1455,6 +1455,12 @@ def mlong_calls : Flag<["-"], "mlong-cal HelpText<"Generate branches with extended addressability, usually via indirect jumps.">; def mno_long_calls : Flag<["-"], "mno-long-calls">, Group<m_Group>, HelpText<"Restore the default behaviour of not generating long calls">; +def mexecute_only : Flag<["-"], "mexecute-only">, Group<m_arm_Features_Group>, + HelpText<"Disallow generation of data access to code sections (ARM only)">; +def mno_execute_only : Flag<["-"], "mno-execute-only">, Group<m_arm_Features_Group>, + HelpText<"Allow generation of data access to code sections (ARM only)">; +def mpure_code : Flag<["-"], "mpure-code">, Alias<mexecute_only>; // Alias for GCC compatibility +def mno_pure_code : Flag<["-"], "mno-pure-code">, Alias<mno_execute_only>; def mtvos_version_min_EQ : Joined<["-"], "mtvos-version-min=">, Group<m_Group>; def mappletvos_version_min_EQ : Joined<["-"], "mappletvos-version-min=">, Alias<mtvos_version_min_EQ>; def mtvos_simulator_version_min_EQ : Joined<["-"], "mtvos-simulator-version-min=">, Alias<mtvos_version_min_EQ>; Modified: cfe/trunk/lib/Driver/Tools.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/Tools.cpp?rev=289786&r1=289785&r2=289786&view=diff ============================================================================== --- cfe/trunk/lib/Driver/Tools.cpp (original) +++ cfe/trunk/lib/Driver/Tools.cpp Thu Dec 15 01:59:24 2016 @@ -1001,6 +1001,7 @@ arm::FloatABI arm::getARMFloatABI(const static void getARMTargetFeatures(const ToolChain &TC, const llvm::Triple &Triple, const ArgList &Args, + ArgStringList &CmdArgs, std::vector<StringRef> &Features, bool ForAS) { const Driver &D = TC.getDriver(); @@ -1139,6 +1140,28 @@ static void getARMTargetFeatures(const T Features.push_back("+long-calls"); } + // Generate execute-only output (no data access to code sections). + // Supported only on ARMv6T2 and ARMv7 and above. + // Cannot be combined with -mno-movt or -mlong-calls + if (Arg *A = Args.getLastArg(options::OPT_mexecute_only, options::OPT_mno_execute_only)) { + if (A->getOption().matches(options::OPT_mexecute_only)) { + if (getARMSubArchVersionNumber(Triple) < 7 && + llvm::ARM::parseArch(Triple.getArchName()) != llvm::ARM::AK_ARMV6T2) + D.Diag(diag::err_target_unsupported_execute_only) << Triple.getArchName(); + else if (Arg *B = Args.getLastArg(options::OPT_mno_movt)) + D.Diag(diag::err_opt_not_valid_with_opt) << A->getAsString(Args) << B->getAsString(Args); + // Long calls create constant pool entries and have not yet been fixed up + // to play nicely with execute-only. Hence, they cannot be used in + // execute-only code for now + else if (Arg *B = Args.getLastArg(options::OPT_mlong_calls, options::OPT_mno_long_calls)) { + if (B->getOption().matches(options::OPT_mlong_calls)) + D.Diag(diag::err_opt_not_valid_with_opt) << A->getAsString(Args) << B->getAsString(Args); + } + + CmdArgs.push_back("-arm-execute-only"); + } + } + // Kernel code has more strict alignment requirements. if (KernelOrKext) Features.push_back("+strict-align"); @@ -2703,7 +2726,7 @@ static void getTargetFeatures(const Tool case llvm::Triple::armeb: case llvm::Triple::thumb: case llvm::Triple::thumbeb: - getARMTargetFeatures(TC, Triple, Args, Features, ForAS); + getARMTargetFeatures(TC, Triple, Args, CmdArgs, Features, ForAS); break; case llvm::Triple::ppc: Added: cfe/trunk/test/Driver/arm-execute-only.c URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Driver/arm-execute-only.c?rev=289786&view=auto ============================================================================== --- cfe/trunk/test/Driver/arm-execute-only.c (added) +++ cfe/trunk/test/Driver/arm-execute-only.c Thu Dec 15 01:59:24 2016 @@ -0,0 +1,99 @@ +// RUN: %clang -target armv6t2-eabi -### %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY + +// RUN: %clang -target armv6t2-eabi -### -mexecute-only %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-EXECUTE-ONLY + +// RUN: %clang -target armv6t2-eabi -### -mexecute-only -mno-execute-only %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY + +// RUN: %clang -target armv7m-eabi -### %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY + +// RUN: %clang -target armv7m-eabi -### -mexecute-only %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-EXECUTE-ONLY + +// RUN: %clang -target armv7m-eabi -### -mexecute-only -mno-execute-only %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY + +// RUN: %clang -target armv8m.base-eabi -### %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY + +// RUN: %clang -target armv8m.base-eabi -### -mexecute-only %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-EXECUTE-ONLY + +// RUN: %clang -target armv8m.base-eabi -### -mexecute-only -mno-execute-only %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY + +// RUN: %clang -target armv8m.main-eabi -### %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY + +// RUN: %clang -target armv8m.main-eabi -### -mexecute-only %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-EXECUTE-ONLY + +// RUN: %clang -target armv8m.main-eabi -### -mexecute-only -mno-execute-only %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY + +// RUN: not %clang -c -target thumbv6m-eabi -mexecute-only %s 2>&1 | \ +// RUN: FileCheck --check-prefix CHECK-EXECUTE-ONLY-NOT-SUPPORTED %s + +// RUN: not %clang -target armv8m.main-eabi -mexecute-only -mno-movt %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-EXECUTE-ONLY-NO-MOVT + +// RUN: not %clang -target armv8m.main-eabi -mexecute-only -mlong-calls %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-EXECUTE-ONLY-LONG-CALLS + + +// -mpure-code flag for GCC compatibility +// RUN: %clang -target armv6t2-eabi -### %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY + +// RUN: %clang -target armv6t2-eabi -### -mpure-code %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-EXECUTE-ONLY + +// RUN: %clang -target armv6t2-eabi -### -mpure-code -mno-pure-code %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY + +// RUN: %clang -target armv7m-eabi -### %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY + +// RUN: %clang -target armv7m-eabi -### -mpure-code %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-EXECUTE-ONLY + +// RUN: %clang -target armv7m-eabi -### -mpure-code -mno-pure-code %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY + +// RUN: %clang -target armv8m.base-eabi -### %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY + +// RUN: %clang -target armv8m.base-eabi -### -mpure-code %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-EXECUTE-ONLY + +// RUN: %clang -target armv8m.base-eabi -### -mpure-code -mno-pure-code %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY + +// RUN: %clang -target armv8m.main-eabi -### %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY + +// RUN: %clang -target armv8m.main-eabi -### -mpure-code %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-EXECUTE-ONLY + +// RUN: %clang -target armv8m.main-eabi -### -mpure-code -mno-pure-code %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY + +// RUN: not %clang -c -target thumbv6m-eabi -mpure-code %s 2>&1 | \ +// RUN: FileCheck --check-prefix CHECK-EXECUTE-ONLY-NOT-SUPPORTED %s + +// RUN: not %clang -target armv8m.main-eabi -mpure-code -mno-movt %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-EXECUTE-ONLY-NO-MOVT + +// RUN: not %clang -target armv8m.main-eabi -mpure-code -mlong-calls %s 2>&1 \ +// RUN: | FileCheck %s -check-prefix CHECK-EXECUTE-ONLY-LONG-CALLS + +// +// CHECK-NO-EXECUTE-ONLY-NOT: "-arm-execute-only" +// CHECK-EXECUTE-ONLY: "-arm-execute-only" + +// CHECK-EXECUTE-ONLY-NOT-SUPPORTED: error: execute only is not supported for the thumbv6m sub-architecture +// CHECK-EXECUTE-ONLY-NO-MOVT: error: option '-mexecute-only' cannot be specified with '-mno-movt' +// CHECK-EXECUTE-ONLY-LONG-CALLS: error: option '-mexecute-only' cannot be specified with '-mlong-calls' _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
