From: Chandler Carruth Date: Tue, 27 Mar 2012 23:58:37 +0000 (+0000) Subject: Move the emission of strict enum range metadata behind a flag (the same X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=82fe6aea407a5a09a6131452ce622087ba83880d;p=clang Move the emission of strict enum range metadata behind a flag (the same flag as GCC uses: -fstrict-enums). There is a *lot* of code making unwarranted assumptions about the underlying type of enums, and it doesn't seem entirely reasonable to eagerly break all of it. Much more importantly, the current state of affairs is *very* good at optimizing based upon this information, which causes failures that are very distant from the actual enum. Before we push for enabling this by default, I think we need to implement -fcatch-undefined-behavior support for instrumenting and trapping whenever we store or load a value outside of the range. That way we can track down the misbehaving code very quickly. I discussed this with Rafael, and currently the only important cases he is aware of are the bool range-based optimizations which are staying hard enabled. We've not seen any issue with those either, and they are much more important for performance. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@153550 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/include/clang/Driver/CC1Options.td b/include/clang/Driver/CC1Options.td index 46c4ed89b5..956f2a65ce 100644 --- a/include/clang/Driver/CC1Options.td +++ b/include/clang/Driver/CC1Options.td @@ -178,6 +178,9 @@ def ffunction_sections : Flag<"-ffunction-sections">, HelpText<"Place each function in its own section (ELF Only)">; def fdata_sections : Flag<"-fdata-sections">, HelpText<"Place each data in its own section (ELF Only)">; +def fstrict_enums : Flag<"-fstrict-enums">, + HelpText<"Enable optimizations based on the strict definition of an enum's " + "value range.">; def ftrap_function_EQ : Joined<"-ftrap-function=">, HelpText<"Issue call to specified function rather than a trap instruction">; def funroll_loops : Flag<"-funroll-loops">, diff --git a/include/clang/Driver/Options.td b/include/clang/Driver/Options.td index eab8e8f331..6bc0a7d0b5 100644 --- a/include/clang/Driver/Options.td +++ b/include/clang/Driver/Options.td @@ -444,6 +444,7 @@ def fno_show_source_location : Flag<"-fno-show-source-location">, Group def fno_spell_checking : Flag<"-fno-spell-checking">, Group; def fno_stack_protector : Flag<"-fno-stack-protector">, Group; def fno_strict_aliasing : Flag<"-fno-strict-aliasing">, Group; +def fno_strict_enums : Flag<"-fno-strict-enums">, Group; def fno_strict_overflow : Flag<"-fno-strict-overflow">, Group; def fno_threadsafe_statics : Flag<"-fno-threadsafe-statics">, Group; def fno_use_cxa_atexit : Flag<"-fno-use-cxa-atexit">, Group; @@ -515,6 +516,7 @@ def fsigned_char : Flag<"-fsigned-char">, Group; def fstack_protector_all : Flag<"-fstack-protector-all">, Group; def fstack_protector : Flag<"-fstack-protector">, Group; def fstrict_aliasing : Flag<"-fstrict-aliasing">, Group; +def fstrict_enums : Flag<"-fstrict-enums">, Group; def fstrict_overflow : Flag<"-fstrict-overflow">, Group; def fsyntax_only : Flag<"-fsyntax-only">, Flags<[DriverOption]>; def ftabstop_EQ : Joined<"-ftabstop=">, Group; diff --git a/include/clang/Frontend/CodeGenOptions.h b/include/clang/Frontend/CodeGenOptions.h index 59509331a0..e844f8869c 100644 --- a/include/clang/Frontend/CodeGenOptions.h +++ b/include/clang/Frontend/CodeGenOptions.h @@ -94,6 +94,7 @@ public: unsigned SaveTempLabels : 1; /// Save temporary labels. unsigned SimplifyLibCalls : 1; /// Set when -fbuiltin is enabled. unsigned SoftFloat : 1; /// -soft-float. + unsigned StrictEnums : 1; /// Optimize based on strict enum definition. unsigned TimePasses : 1; /// Set when -ftime-report is enabled. unsigned UnitAtATime : 1; /// Unused. For mirroring GCC optimization /// selection. @@ -205,6 +206,7 @@ public: SaveTempLabels = 0; SimplifyLibCalls = 1; SoftFloat = 0; + StrictEnums = 0; TimePasses = 0; UnitAtATime = 1; UnrollLoops = 0; diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp index a9f87e67d4..511914884f 100644 --- a/lib/CodeGen/CGExpr.cpp +++ b/lib/CodeGen/CGExpr.cpp @@ -872,8 +872,9 @@ static bool hasBooleanRepresentation(QualType Ty) { llvm::MDNode *CodeGenFunction::getRangeForLoadFromType(QualType Ty) { const EnumType *ET = Ty->getAs(); - bool IsRegularCPlusPlusEnum = getLangOpts().CPlusPlus && ET && - !ET->getDecl()->isFixed(); + bool IsRegularCPlusPlusEnum = (getLangOpts().CPlusPlus && ET && + CGM.getCodeGenOpts().StrictEnums && + !ET->getDecl()->isFixed()); bool IsBool = hasBooleanRepresentation(Ty); llvm::Type *LTy; if (!IsBool && !IsRegularCPlusPlusEnum) diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp index 52c22b13a4..ff034d685d 100644 --- a/lib/Driver/Tools.cpp +++ b/lib/Driver/Tools.cpp @@ -1487,6 +1487,9 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA, options::OPT_fno_strict_aliasing, getToolChain().IsStrictAliasingDefault())) CmdArgs.push_back("-relaxed-aliasing"); + if (Args.hasFlag(options::OPT_fstrict_enums, options::OPT_fno_strict_enums, + false)) + CmdArgs.push_back("-fstrict-enums"); if (!Args.hasFlag(options::OPT_foptimize_sibling_calls, options::OPT_fno_optimize_sibling_calls)) CmdArgs.push_back("-mdisable-tail-calls"); diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp index 0f68591c96..48b8049cd0 100644 --- a/lib/Frontend/CompilerInvocation.cpp +++ b/lib/Frontend/CompilerInvocation.cpp @@ -286,6 +286,8 @@ static void CodeGenOptsToArgs(const CodeGenOptions &Opts, ToArgsList &Res) { Res.push_back("-fno-dwarf-directory-asm"); if (Opts.SoftFloat) Res.push_back("-msoft-float"); + if (Opts.StrictEnums) + Res.push_back("-fstrict-enums"); if (Opts.UnwindTables) Res.push_back("-munwind-tables"); if (Opts.RelocationModel != "pic") @@ -1135,6 +1137,7 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK, Opts.NoDwarf2CFIAsm = Args.hasArg(OPT_fno_dwarf2_cfi_asm); Opts.NoDwarfDirectoryAsm = Args.hasArg(OPT_fno_dwarf_directory_asm); Opts.SoftFloat = Args.hasArg(OPT_msoft_float); + Opts.StrictEnums = Args.hasArg(OPT_fstrict_enums); Opts.UnsafeFPMath = Args.hasArg(OPT_menable_unsafe_fp_math) || Args.hasArg(OPT_cl_unsafe_math_optimizations) || Args.hasArg(OPT_cl_fast_relaxed_math); diff --git a/test/CodeGenCXX/pr12251.cpp b/test/CodeGenCXX/pr12251.cpp index 310e60d3e5..a9920c0733 100644 --- a/test/CodeGenCXX/pr12251.cpp +++ b/test/CodeGenCXX/pr12251.cpp @@ -1,4 +1,5 @@ -// RUN: %clang_cc1 %s -emit-llvm -O1 -relaxed-aliasing -std=c++11 -o - | FileCheck %s +// RUN: %clang_cc1 %s -emit-llvm -O1 -relaxed-aliasing -fstrict-enums -std=c++11 -o - | FileCheck %s +// RUN: %clang_cc1 %s -emit-llvm -O1 -relaxed-aliasing -std=c++11 -o - | FileCheck --check-prefix=NO-STRICT-ENUMS %s bool f(bool *x) { return *x; @@ -6,6 +7,12 @@ bool f(bool *x) { // CHECK: define zeroext i1 @_Z1fPb // CHECK: load i8* %{{.*}}, align 1, !range !0 +// Only enum-tests follow. Ensure that after the bool test, no further range +// metadata shows up when strict enums are disabled. +// NO-STRICT-ENUMS: define zeroext i1 @_Z1fPb +// NO-STRICT-ENUMS: load i8* %{{.*}}, align 1, !range !0 +// NO-STRICT-ENUMS-NOT: !range + enum e1 { }; e1 g1(e1 *x) { return *x;