llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang-codegen Author: None (haopliu) <details> <summary>Changes</summary> Add a clang flag, "-ftrivial-auto-var-init-size-bound=" so that clang skips auto-init a variable if its size exceeds the flag setting. Note that this skipping doesn't apply to runtime-sized variables like VLA. Considerations: "__attribute__((uninitialized))" can be used to manually opt variables out. However, there are thousands of large variables (e.g., >=1KB, most of them are arrays and used as buffers) in big codebase. Manually opting them out one by one is not efficient. --- Full diff: https://github.com/llvm/llvm-project/pull/74777.diff 7 Files Affected: - (modified) clang/include/clang/Basic/DiagnosticDriverKinds.td (+7) - (modified) clang/include/clang/Basic/LangOptions.def (+2) - (modified) clang/include/clang/Driver/Options.td (+4) - (modified) clang/lib/CodeGen/CGDecl.cpp (+9) - (modified) clang/lib/Driver/ToolChains/Clang.cpp (+15) - (added) clang/test/CodeGenCXX/auto-var-init-size-bound.cpp (+82) - (modified) clang/test/Driver/clang_f_opts.c (+13) ``````````diff diff --git a/clang/include/clang/Basic/DiagnosticDriverKinds.td b/clang/include/clang/Basic/DiagnosticDriverKinds.td index 676f1a62b49dd..5fd097154d0fa 100644 --- a/clang/include/clang/Basic/DiagnosticDriverKinds.td +++ b/clang/include/clang/Basic/DiagnosticDriverKinds.td @@ -656,6 +656,13 @@ def err_drv_trivial_auto_var_init_stop_after_missing_dependency : Error< def err_drv_trivial_auto_var_init_stop_after_invalid_value : Error< "'-ftrivial-auto-var-init-stop-after=*' only accepts positive integers">; +def err_drv_trivial_auto_var_init_size_bound_missing_dependency : Error< + "'-ftrivial-auto-var-init-size-bound=*' is used without " + "'-ftrivial-auto-var-init=zero' or '-ftrivial-auto-var-init=pattern'">; + +def err_drv_trivial_auto_var_init_size_bound_invalid_value : Error< + "'-ftrivial-auto-var-init-size-bound=*' only accepts positive integers (in bytes)">; + def warn_drv_msp430_hwmult_unsupported : Warning< "the given MCU does not support hardware multiply, but '-mhwmult' is set to " "%0">, InGroup<InvalidCommandLineArgument>; diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def index c3d5399905a3f..8325561fc6d23 100644 --- a/clang/include/clang/Basic/LangOptions.def +++ b/clang/include/clang/Basic/LangOptions.def @@ -376,6 +376,8 @@ ENUM_LANGOPT(TrivialAutoVarInit, TrivialAutoVarInitKind, 2, TrivialAutoVarInitKi "trivial automatic variable initialization") VALUE_LANGOPT(TrivialAutoVarInitStopAfter, 32, 0, "stop trivial automatic variable initialization after the specified number of instances. Must be greater than 0.") +VALUE_LANGOPT(TrivialAutoVarInitSizeBound, 32, 0, + "stop trivial automatic variable initialization if var size exceeds the specified number of instances (in bytes). Must be greater than 0.") ENUM_LANGOPT(SignedOverflowBehavior, SignedOverflowBehaviorTy, 2, SOB_Undefined, "signed integer overflow handling") ENUM_LANGOPT(ThreadModel , ThreadModelKind, 2, ThreadModelKind::POSIX, "Thread Model") diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td index 0eec2b3526376..f92dbd07de20d 100644 --- a/clang/include/clang/Driver/Options.td +++ b/clang/include/clang/Driver/Options.td @@ -3627,6 +3627,10 @@ def ftrivial_auto_var_init_stop_after : Joined<["-"], "ftrivial-auto-var-init-st Visibility<[ClangOption, CC1Option, CLOption, DXCOption]>, HelpText<"Stop initializing trivial automatic stack variables after the specified number of instances">, MarshallingInfoInt<LangOpts<"TrivialAutoVarInitStopAfter">>; +def ftrivial_auto_var_init_size_bound : Joined<["-"], "ftrivial-auto-var-init-size-bound=">, Group<f_Group>, + Visibility<[ClangOption, CC1Option, CLOption, DXCOption]>, + HelpText<"Stop initializing trivial automatic stack variables if var size exceeds the specified number of instances (in bytes)">, + MarshallingInfoInt<LangOpts<"TrivialAutoVarInitSizeBound">>; def fstandalone_debug : Flag<["-"], "fstandalone-debug">, Group<f_Group>, Visibility<[ClangOption, CLOption, DXCOption]>, HelpText<"Emit full debug info for all types used by the program">; diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp index a5da0aa2965a0..1f9650e60d5e0 100644 --- a/clang/lib/CodeGen/CGDecl.cpp +++ b/clang/lib/CodeGen/CGDecl.cpp @@ -1759,20 +1759,29 @@ void CodeGenFunction::emitZeroOrPatternForAutoVarInit(QualType type, const VarDecl &D, Address Loc) { auto trivialAutoVarInit = getContext().getLangOpts().getTrivialAutoVarInit(); + auto trivialAutoVarInitSizeBound = + getContext().getLangOpts().TrivialAutoVarInitSizeBound; CharUnits Size = getContext().getTypeSizeInChars(type); bool isVolatile = type.isVolatileQualified(); if (!Size.isZero()) { + auto allocSize = CGM.getDataLayout().getTypeAllocSize(Loc.getElementType()); switch (trivialAutoVarInit) { case LangOptions::TrivialAutoVarInitKind::Uninitialized: llvm_unreachable("Uninitialized handled by caller"); case LangOptions::TrivialAutoVarInitKind::Zero: if (CGM.stopAutoInit()) return; + if (trivialAutoVarInitSizeBound > 0 && + allocSize >= trivialAutoVarInitSizeBound) + return; emitStoresForZeroInit(CGM, D, Loc, isVolatile, Builder); break; case LangOptions::TrivialAutoVarInitKind::Pattern: if (CGM.stopAutoInit()) return; + if (trivialAutoVarInitSizeBound > 0 && + allocSize >= trivialAutoVarInitSizeBound) + return; emitStoresForPatternInit(CGM, D, Loc, isVolatile, Builder); break; } diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp index f02f7c841b91f..669c85c8c7722 100644 --- a/clang/lib/Driver/ToolChains/Clang.cpp +++ b/clang/lib/Driver/ToolChains/Clang.cpp @@ -3436,6 +3436,21 @@ static void RenderTrivialAutoVarInitOptions(const Driver &D, CmdArgs.push_back( Args.MakeArgString("-ftrivial-auto-var-init-stop-after=" + Val)); } + + if (Arg *A = + Args.getLastArg(options::OPT_ftrivial_auto_var_init_size_bound)) { + if (!Args.hasArg(options::OPT_ftrivial_auto_var_init) || + StringRef( + Args.getLastArg(options::OPT_ftrivial_auto_var_init)->getValue()) == + "uninitialized") + D.Diag(diag::err_drv_trivial_auto_var_init_size_bound_missing_dependency); + A->claim(); + StringRef Val = A->getValue(); + if (std::stoi(Val.str()) <= 0) + D.Diag(diag::err_drv_trivial_auto_var_init_size_bound_invalid_value); + CmdArgs.push_back( + Args.MakeArgString("-ftrivial-auto-var-init-size-bound=" + Val)); + } } static void RenderOpenCLOptions(const ArgList &Args, ArgStringList &CmdArgs, diff --git a/clang/test/CodeGenCXX/auto-var-init-size-bound.cpp b/clang/test/CodeGenCXX/auto-var-init-size-bound.cpp new file mode 100644 index 0000000000000..1f6c2b143d397 --- /dev/null +++ b/clang/test/CodeGenCXX/auto-var-init-size-bound.cpp @@ -0,0 +1,82 @@ +// Pattern related size bound tests: 1, 8, 4096, 4097 +// RUN: %clang_cc1 -triple x86_64-unknown-unknown -ftrivial-auto-var-init=pattern -ftrivial-auto-var-init-size-bound=1 %s -emit-llvm -o - | FileCheck -check-prefix=PATTERN-COMMON -check-prefix=PATTERN-BOUND-1 %s +// RUN: %clang_cc1 -triple x86_64-unknown-unknown -ftrivial-auto-var-init=pattern -ftrivial-auto-var-init-size-bound=8 %s -emit-llvm -o - | FileCheck -check-prefix=PATTERN-COMMON -check-prefix=PATTERN-BOUND-8 %s +// RUN: %clang_cc1 -triple x86_64-unknown-unknown -ftrivial-auto-var-init=pattern -ftrivial-auto-var-init-size-bound=4096 %s -emit-llvm -o - | FileCheck -check-prefix=PATTERN-COMMON -check-prefix=PATTERN-BOUND-4096 %s +// RUN: %clang_cc1 -triple x86_64-unknown-unknown -ftrivial-auto-var-init=pattern -ftrivial-auto-var-init-size-bound=4097 %s -emit-llvm -o - | FileCheck -check-prefix=PATTERN-COMMON -check-prefix=PATTERN-BOUND-4097 %s +// +// Zero related size bound tests: 1, 8, 4096, 4097 +// RUN: %clang_cc1 -triple x86_64-unknown-unknown -ftrivial-auto-var-init=zero -ftrivial-auto-var-init-size-bound=1 %s -emit-llvm -o - | FileCheck -check-prefix=ZERO-COMMON -check-prefix=ZERO-BOUND-1 %s +// RUN: %clang_cc1 -triple x86_64-unknown-unknown -ftrivial-auto-var-init=zero -ftrivial-auto-var-init-size-bound=8 %s -emit-llvm -o - | FileCheck -check-prefix=ZERO-COMMON -check-prefix=ZERO-BOUND-8 %s +// RUN: %clang_cc1 -triple x86_64-unknown-unknown -ftrivial-auto-var-init=zero -ftrivial-auto-var-init-size-bound=4096 %s -emit-llvm -o - | FileCheck -check-prefix=ZERO-COMMON -check-prefix=ZERO-BOUND-4096 %s +// RUN: %clang_cc1 -triple x86_64-unknown-unknown -ftrivial-auto-var-init=zero -ftrivial-auto-var-init-size-bound=4097 %s -emit-llvm -o - | FileCheck -check-prefix=ZERO-COMMON -check-prefix=ZERO-BOUND-4097 %s + +#define ARRLEN 1024 + +int foo(unsigned n) { + bool var_size_1; + long var_size_8 = 123; + void *var_size_8p; + int var_size_4096[ARRLEN]; + // VLA, non-constant size + int var_vla[n]; + // builtin, non-constant size + var_size_8p = __builtin_alloca(sizeof(unsigned long long) * n); + // There are 6 variables: var_size_1, var_size_8, var_size_8p, var_size_4096, + // var_vla, and a builtin anonymous var ("%5"). + // "var_vla" and "%5" have a non-constant size, and they should be auto-inited + // disregarding the size bound. + // - Size bound 1: "var_vla" and "%5" + // - Size bound 8: "var_size_1", "var_vla", and "%5" + // - Size bound 4096: "var_size_1", "var_size_8", "var_size_8p", + // "var_vla", and "%5" + // - Size bound 4097: "var_size_1", "var_size_8", "var_size_8p", + // "var_size_4096", "var_vla", and "%5" + // + // PATTERN-BOUND-1-NOT: store i8 -86, ptr %var_size_1, align 1, !annotation [[AUTO_INIT:!.+]] + // PATTERN-BOUND-1-NOT: store i64 -6148914691236517206, ptr %var_size_8, align 8, !annotation [[AUTO_INIT:!.+]] + // PATTERN-BOUND-1-NOT: store ptr inttoptr (i64 -6148914691236517206 to ptr), ptr %var_size_8p, align 8, !annotation [[AUTO_INIT:!.+]] + // PATTERN-BOUND-1-NOT: call void @llvm.memset.p0.i64(ptr align 16 %var_size_4096, i8 -86, i64 4096, i1 false), !annotation [[AUTO_INIT:!.+]] + + // PATTERN-BOUND-8: store i8 -86, ptr %var_size_1, align 1, !annotation [[AUTO_INIT:!.+]] + // PATTERN-BOUND-8-NOT: store i64 -6148914691236517206, ptr %var_size_8, align 8, !annotation [[AUTO_INIT:!.+]] + // PATTERN-BOUND-8-NOT: store ptr inttoptr (i64 -6148914691236517206 to ptr), ptr %var_size_8p, align 8, !annotation [[AUTO_INIT:!.+]] + // PATTERN-BOUND-8-NOT: call void @llvm.memset.p0.i64(ptr align 16 %var_size_4096, i8 -86, i64 4096, i1 false), !annotation [[AUTO_INIT:!.+]] + + // PATTERN-BOUND-4096: store i8 -86, ptr %var_size_1, align 1, !annotation [[AUTO_INIT:!.+]] + // PATTERN-BOUND-4096: store i64 -6148914691236517206, ptr %var_size_8, align 8, !annotation [[AUTO_INIT:!.+]] + // PATTERN-BOUND-4096: store ptr inttoptr (i64 -6148914691236517206 to ptr), ptr %var_size_8p, align 8, !annotation [[AUTO_INIT:!.+]] + // PATTERN-BOUND-4096-NOT: call void @llvm.memset.p0.i64(ptr align 16 %var_size_4096, i8 -86, i64 4096, i1 false), !annotation [[AUTO_INIT:!.+]] + + // PATTERN-BOUND-4097: store i8 -86, ptr %var_size_1, align 1, !annotation [[AUTO_INIT:!.+]] + // PATTERN-BOUND-4097: store i64 -6148914691236517206, ptr %var_size_8, align 8, !annotation [[AUTO_INIT:!.+]] + // PATTERN-BOUND-4097: store ptr inttoptr (i64 -6148914691236517206 to ptr), ptr %var_size_8p, align 8, !annotation [[AUTO_INIT:!.+]] + // PATTERN-BOUND-4097: call void @llvm.memset.p0.i64(ptr align 16 %var_size_4096, i8 -86, i64 4096, i1 false), !annotation [[AUTO_INIT:!.+]] + + // PATTERN-COMMON: call void @llvm.memcpy.p0.p0.i64(ptr align 4 %vla.cur, ptr align 4 @__const._Z3fooj.var_vla, i64 4, i1 false), !annotation [[AUTO_INIT:!.+]] + // PATTERN-COMMON: call void @llvm.memset.p0.i64(ptr align 16 %5, i8 -86, i64 %mul, i1 false), !annotation [[AUTO_INIT:!.+]] + + // ZERO-BOUND-1-NOT: store i8 0, ptr %var_size_1, align 1, !annotation [[AUTO_INIT:!.+]] + // ZERO-BOUND-1-NOT: store i64 0, ptr %var_size_8, align 8, !annotation [[AUTO_INIT:!.+]] + // ZERO-BOUND-1-NOT: store ptr null, ptr %var_size_8p, align 8, !annotation [[AUTO_INIT:!.+]] + // ZERO-BOUND-1-NOT: call void @llvm.memset.p0.i64(ptr align 16 %var_size_4096, i8 0, i64 4096, i1 false), !annotation [[AUTO_INIT:!.+]] + + // ZERO-BOUND-8: store i8 0, ptr %var_size_1, align 1, !annotation [[AUTO_INIT:!.+]] + // ZERO-BOUND-8-NOT: store i64 0, ptr %var_size_8, align 8, !annotation [[AUTO_INIT:!.+]] + // ZERO-BOUND-8-NOT: store ptr null, ptr %var_size_8p, align 8, !annotation [[AUTO_INIT:!.+]] + // ZERO-BOUND-8-NOT: call void @llvm.memset.p0.i64(ptr align 16 %var_size_4096, i8 0, i64 4096, i1 false), !annotation [[AUTO_INIT:!.+]] + + // ZERO-BOUND-4096: store i8 0, ptr %var_size_1, align 1, !annotation [[AUTO_INIT:!.+]] + // ZERO-BOUND-4096: store i64 0, ptr %var_size_8, align 8, !annotation [[AUTO_INIT:!.+]] + // ZERO-BOUND-4096: store ptr null, ptr %var_size_8p, align 8, !annotation [[AUTO_INIT:!.+]] + // ZERO-BOUND-4096-NOT: call void @llvm.memset.p0.i64(ptr align 16 %var_size_4096, i8 0, i64 4096, i1 false), !annotation [[AUTO_INIT:!.+]] + + // ZERO-BOUND-4097: store i8 0, ptr %var_size_1, align 1, !annotation [[AUTO_INIT:!.+]] + // ZERO-BOUND-4097: store i64 0, ptr %var_size_8, align 8, !annotation [[AUTO_INIT:!.+]] + // ZERO-BOUND-4097: store ptr null, ptr %var_size_8p, align 8, !annotation [[AUTO_INIT:!.+]] + // ZERO-BOUND-4097: call void @llvm.memset.p0.i64(ptr align 16 %var_size_4096, i8 0, i64 4096, i1 false), !annotation [[AUTO_INIT:!.+]] + + // ZERO-COMMON: call void @llvm.memset.p0.i64(ptr align 16 %vla, i8 0, i64 %3, i1 false), !annotation [[AUTO_INIT:!.+]] + // ZERO-COMMON: call void @llvm.memset.p0.i64(ptr align 16 %5, i8 0, i64 %mul, i1 false), !annotation [[AUTO_INIT:!.+]] + + return 0; +} diff --git a/clang/test/Driver/clang_f_opts.c b/clang/test/Driver/clang_f_opts.c index ebe8a0520bf0f..7f947d2de5c6e 100644 --- a/clang/test/Driver/clang_f_opts.c +++ b/clang/test/Driver/clang_f_opts.c @@ -585,6 +585,19 @@ // CHECK-TRIVIAL-PATTERN-STOP-AFTER-INVALID-VALUE: only accepts positive integers // CHECK-TRIVIAL-ZERO-STOP-AFTER-INVALID-VALUE: only accepts positive integers +// RUN: %clang -### -S -ftrivial-auto-var-init=pattern -ftrivial-auto-var-init-size-bound=1024 %s 2>&1 | FileCheck -check-prefix=CHECK-TRIVIAL-PATTERN-SIZE-BOUND %s +// RUN: %clang -### -S -ftrivial-auto-var-init=zero -ftrivial-auto-var-init-size-bound=1024 %s 2>&1 | FileCheck -check-prefix=CHECK-TRIVIAL-ZERO-SIZE-BOUND %s +// RUN: not %clang -### -S -ftrivial-auto-var-init-size-bound=1024 %s 2>&1 | FileCheck -check-prefix=CHECK-TRIVIAL-SIZE-BOUND-MISSING-DEPENDENCY %s +// RUN: not %clang -### -S -ftrivial-auto-var-init=pattern -ftrivial-auto-var-init-size-bound=0 %s 2>&1 | FileCheck -check-prefix=CHECK-TRIVIAL-PATTERN-SIZE-BOUND-INVALID-VALUE %s +// RUN: not %clang -### -S -ftrivial-auto-var-init=zero -ftrivial-auto-var-init-size-bound=0 %s 2>&1 | FileCheck -check-prefix=CHECK-TRIVIAL-ZERO-SIZE-BOUND-INVALID-VALUE %s +// CHECK-TRIVIAL-PATTERN-SIZE-BOUND-NOT: is used without '-ftrivial-auto-var-init' +// CHECK-TRIVIAL-PATTERN-SIZE-BOUND-NOT: only accepts positive integers (in bytes) +// CHECK-TRIVIAL-ZERO-SIZE-BOUND-NOT: is used without '-ftrivial-auto-var-init' +// CHECK-TRIVIAL-ZERO-SIZE-BOUND-NOT: only accepts positive integers (in bytes) +// CHECK-TRIVIAL-SIZE-BOUND-MISSING-DEPENDENCY: used without '-ftrivial-auto-var-init=zero' or +// CHECK-TRIVIAL-PATTERN-SIZE-BOUND-INVALID-VALUE: only accepts positive integers (in bytes) +// CHECK-TRIVIAL-ZERO-SIZE-BOUND-INVALID-VALUE: only accepts positive integers (in bytes) + // RUN: %clang -### -S -fno-temp-file %s 2>&1 | FileCheck -check-prefix=CHECK-NO-TEMP-FILE %s // CHECK-NO-TEMP-FILE: "-fno-temp-file" `````````` </details> https://github.com/llvm/llvm-project/pull/74777 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
