diff --git a/clang/include/clang/AST/ASTContext.h b/clang/include/clang/AST/ASTContext.h --- a/clang/include/clang/AST/ASTContext.h +++ b/clang/include/clang/AST/ASTContext.h @@ -552,6 +552,8 @@ /// AST objects will be released when the ASTContext itself is destroyed. mutable llvm::BumpPtrAllocator BumpAlloc; + + mutable unsigned NumAutoVarInit = 0; /// Allocator for partial diagnostics. PartialDiagnostic::StorageAllocator DiagAllocator; @@ -632,6 +634,14 @@ /// Return the total memory used for various side tables. size_t getSideTableAllocatedMemory() const; + void countAutoVarInit() const { + ++NumAutoVarInit; + } + + unsigned getAutoVarInit() { + return NumAutoVarInit; + } + PartialDiagnostic::StorageAllocator &getDiagAllocator() { return DiagAllocator; } diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def --- a/clang/include/clang/Basic/LangOptions.def +++ b/clang/include/clang/Basic/LangOptions.def @@ -293,6 +293,8 @@ "stack protector mode") ENUM_LANGOPT(TrivialAutoVarInit, TrivialAutoVarInitKind, 2, TrivialAutoVarInitKind::Uninitialized, "trivial automatic variable initialization") +VALUE_LANGOPT(TrivialAutoVarInitStopAfter, 32, 0, + "stop trivial automatic variable initialization after the specified number of instances. 0 is ignored.") ENUM_LANGOPT(SignedOverflowBehavior, SignedOverflowBehaviorTy, 2, SOB_Undefined, "signed integer overflow handling") diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td --- a/clang/include/clang/Driver/Options.td +++ b/clang/include/clang/Driver/Options.td @@ -1799,6 +1799,8 @@ def enable_trivial_var_init_zero : Flag<["-"], "enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang">, Flags<[CC1Option, CoreOption]>, HelpText<"Trivial automatic variable initialization to zero is only here for benchmarks, it'll eventually be removed, and I'm OK with that because I'm only using it to benchmark">; +def ftrivial_auto_var_init_stop_after : Joined<["-"], "ftrivial-auto-var-init-stop-after=">, Group, + Flags<[CC1Option, CoreOption]>, HelpText<"Stop initializing trivial automatic stack variables after the specified number of instances">; def fstandalone_debug : Flag<["-"], "fstandalone-debug">, Group, Flags<[CoreOption]>, HelpText<"Emit full debug info for all types used by the program">; def fno_standalone_debug : Flag<["-"], "fno-standalone-debug">, Group, Flags<[CoreOption]>, diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp --- a/clang/lib/CodeGen/CGDecl.cpp +++ b/clang/lib/CodeGen/CGDecl.cpp @@ -1809,6 +1809,15 @@ LangOptions::TrivialAutoVarInitKind::Uninitialized) return; + unsigned StopAfter = getContext().getLangOpts().TrivialAutoVarInitStopAfter; + if (StopAfter) { + auto &AST = D.getASTContext(); + llvm::dbgs() << AST.getAutoVarInit() << "\n"; + if (AST.getAutoVarInit() >= StopAfter) + return; + AST.countAutoVarInit(); + } + // Only initialize a __block's storage: we always initialize the header. if (emission.IsEscapingByRef && !locIsByrefHeader) Loc = emitBlockByrefAddress(Loc, &D, /*follow=*/false); diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp --- a/clang/lib/Driver/ToolChains/Clang.cpp +++ b/clang/lib/Driver/ToolChains/Clang.cpp @@ -3088,6 +3088,13 @@ CmdArgs.push_back( Args.MakeArgString("-ftrivial-auto-var-init=" + TrivialAutoVarInit)); } + + if (Arg *A = Args.getLastArg(options::OPT_ftrivial_auto_var_init_stop_after)) { + A->claim(); + StringRef Val = A->getValue(); + CmdArgs.push_back( + Args.MakeArgString("-ftrivial-auto-var-init-stop-after=" + Val)); + } } static void RenderOpenCLOptions(const ArgList &Args, ArgStringList &CmdArgs) { diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp --- a/clang/lib/Frontend/CompilerInvocation.cpp +++ b/clang/lib/Frontend/CompilerInvocation.cpp @@ -3273,6 +3273,11 @@ Diags.Report(diag::err_drv_invalid_value) << A->getAsString(Args) << Val; } + if (Arg *A = Args.getLastArg(OPT_ftrivial_auto_var_init_stop_after)) { + unsigned Val = (unsigned)std::stoi(A->getValue()); + Opts.TrivialAutoVarInitStopAfter = Val; + } + // Parse -fsanitize= arguments. parseSanitizerKinds("-fsanitize=", Args.getAllArgValues(OPT_fsanitize_EQ), Diags, Opts.Sanitize); diff --git a/clang/test/CodeGenCXX/auto-var-init-stop-after.cpp b/clang/test/CodeGenCXX/auto-var-init-stop-after.cpp new file mode 100644 --- /dev/null +++ b/clang/test/CodeGenCXX/auto-var-init-stop-after.cpp @@ -0,0 +1,27 @@ +// RUN: %clang_cc1 -triple x86_64-unknown-unknown -ftrivial-auto-var-init=pattern -ftrivial-auto-var-init-stop-after=2 %s -emit-llvm -o - | FileCheck %s -check-prefix=PATTERN-STOP-AFTER-2 +// RUN: %clang_cc1 -triple x86_64-unknown-unknown -ftrivial-auto-var-init=pattern -ftrivial-auto-var-init-stop-after=3 %s -emit-llvm -o - | FileCheck %s -check-prefix=PATTERN-STOP-AFTER-3 +// RUN: %clang_cc1 -triple x86_64-unknown-unknown -ftrivial-auto-var-init=zero -ftrivial-auto-var-init-stop-after=2 %s -emit-llvm -o - | FileCheck %s -check-prefix=ZERO-STOP-AFTER-2 +// RUN: %clang_cc1 -triple x86_64-unknown-unknown -ftrivial-auto-var-init=zero -ftrivial-auto-var-init-stop-after=3 %s -emit-llvm -o - | FileCheck %s -check-prefix=ZERO-STOP-AFTER-3 + +#define ARRLEN 10 + +typedef struct { + int i; + char c; +} S; + +int foo () { + long a = 888; + S arr1[ARRLEN], arr2[ARRLEN]; +// PATTERN-STOP-AFTER-2-NOT: %1 = bitcast [10 x %struct.S]* %arr2 to i8* +// PATTERN-STOP-AFTER-2-NOT: call void @llvm.memset.p0i8.i64(i8* align 16 %1, i8 -86, i64 80, i1 false) +// PATTERN-STOP-AFTER-3: %1 = bitcast [10 x %struct.S]* %arr2 to i8* +// PATTERN-STOP-AFTER-3: call void @llvm.memset.p0i8.i64(i8* align 16 %1, i8 -86, i64 80, i1 false) + +// ZERO-STOP-AFTER-2-NOT: %1 = bitcast [10 x %struct.S]* %arr2 to i8* +// ZERO-STOP-AFTER-2-NOT: call void @llvm.memset.p0i8.i64(i8* align 16 %1, i8 0, i64 80, i1 false) +// ZERO-STOP-AFTER-3: %1 = bitcast [10 x %struct.S]* %arr2 to i8* +// ZERO-STOP-AFTER-3: call void @llvm.memset.p0i8.i64(i8* align 16 %1, i8 0, i64 80, i1 false) + + return 0; +} diff --git a/clang/test/Driver/clang_f_opts.c b/clang/test/Driver/clang_f_opts.c --- a/clang/test/Driver/clang_f_opts.c +++ b/clang/test/Driver/clang_f_opts.c @@ -571,8 +571,8 @@ // CHECK-RECORD-GCC-SWITCHES-ESCAPED: "-record-command-line" "{{.+}}with\\ spaces{{.+}}" // RUN: %clang -### -S -ftrivial-auto-var-init=uninitialized %s 2>&1 | FileCheck -check-prefix=CHECK-TRIVIAL-UNINIT %s -// RUN: %clang -### -S -ftrivial-auto-var-init=pattern %s 2>&1 | FileCheck -check-prefix=CHECK-TRIVIAL-PATTERN %s -// RUN: %clang -### -S -ftrivial-auto-var-init=zero -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang %s 2>&1 | FileCheck -check-prefix=CHECK-TRIVIAL-ZERO-GOOD %s +// RUN: %clang -### -S -ftrivial-auto-var-init=pattern -ftrivial-auto-var-init-stop-after=1 %s 2>&1 | FileCheck -check-prefix=CHECK-TRIVIAL-PATTERN %s +// RUN: %clang -### -S -ftrivial-auto-var-init=zero -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang -ftrivial-auto-var-init-stop-after=1 %s 2>&1 | FileCheck -check-prefix=CHECK-TRIVIAL-ZERO-GOOD %s // RUN: %clang -### -S -ftrivial-auto-var-init=zero %s 2>&1 | FileCheck -check-prefix=CHECK-TRIVIAL-ZERO-BAD %s // CHECK-TRIVIAL-UNINIT-NOT: hasn't been enabled // CHECK-TRIVIAL-PATTERN-NOT: hasn't been enabled