jcai19 created this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.
Add -ftrivial-auto-var-init-stop-after= to limit the number of times
stack variables are initialized when -ftrivial-auto-var-init= is used to
initialize stack variables to zero or a pattern. This flag can be used
to bisect uninitialized uses of a stack variable exposed by automatic
variable initialization, such as http://crrev.com/c/2020401.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D77168
Files:
clang/include/clang/Basic/LangOptions.def
clang/include/clang/Driver/Options.td
clang/lib/CodeGen/CGDecl.cpp
clang/lib/Driver/ToolChains/Clang.cpp
clang/lib/Frontend/CompilerInvocation.cpp
Index: clang/lib/Frontend/CompilerInvocation.cpp
===================================================================
--- clang/lib/Frontend/CompilerInvocation.cpp
+++ 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);
Index: clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Clang.cpp
+++ 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) {
Index: clang/lib/CodeGen/CGDecl.cpp
===================================================================
--- clang/lib/CodeGen/CGDecl.cpp
+++ clang/lib/CodeGen/CGDecl.cpp
@@ -1809,6 +1809,19 @@
LangOptions::TrivialAutoVarInitKind::Uninitialized)
return;
+ unsigned StopAfter =
getContext().getLangOpts().TrivialAutoVarInitStopAfter;
+ if (StopAfter) {
+ static unsigned Counter = 0;
+ if (Counter >= StopAfter)
+ return;
+ if (Counter++ == StopAfter - 1) {
+ const DeclContext * CD = D.getParentFunctionOrMethod ();
+ std::string FunctionName =
(cast<FunctionDecl>(CD))->getNameInfo().getAsString();
+ StringRef SourceFileName = CGM.getModule().getSourceFileName();
+ llvm::errs() << "The last variable initialized is " << D.getName() <<
" of function " << FunctionName << " in " << SourceFileName << "\n";
+ }
+ }
+
// Only initialize a __block's storage: we always initialize the header.
if (emission.IsEscapingByRef && !locIsByrefHeader)
Loc = emitBlockByrefAddress(Loc, &D, /*follow=*/false);
Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ 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<f_Group>,
+ Flags<[CC1Option, CoreOption]>, HelpText<"Stop initializing trivial
automatic stack variables after the specified number of instances">;
def fstandalone_debug : Flag<["-"], "fstandalone-debug">, Group<f_Group>,
Flags<[CoreOption]>,
HelpText<"Emit full debug info for all types used by the program">;
def fno_standalone_debug : Flag<["-"], "fno-standalone-debug">,
Group<f_Group>, Flags<[CoreOption]>,
Index: clang/include/clang/Basic/LangOptions.def
===================================================================
--- clang/include/clang/Basic/LangOptions.def
+++ 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")
ENUM_LANGOPT(SignedOverflowBehavior, SignedOverflowBehaviorTy, 2,
SOB_Undefined,
"signed integer overflow handling")
Index: clang/lib/Frontend/CompilerInvocation.cpp
===================================================================
--- clang/lib/Frontend/CompilerInvocation.cpp
+++ 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);
Index: clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Clang.cpp
+++ 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) {
Index: clang/lib/CodeGen/CGDecl.cpp
===================================================================
--- clang/lib/CodeGen/CGDecl.cpp
+++ clang/lib/CodeGen/CGDecl.cpp
@@ -1809,6 +1809,19 @@
LangOptions::TrivialAutoVarInitKind::Uninitialized)
return;
+ unsigned StopAfter = getContext().getLangOpts().TrivialAutoVarInitStopAfter;
+ if (StopAfter) {
+ static unsigned Counter = 0;
+ if (Counter >= StopAfter)
+ return;
+ if (Counter++ == StopAfter - 1) {
+ const DeclContext * CD = D.getParentFunctionOrMethod ();
+ std::string FunctionName = (cast<FunctionDecl>(CD))->getNameInfo().getAsString();
+ StringRef SourceFileName = CGM.getModule().getSourceFileName();
+ llvm::errs() << "The last variable initialized is " << D.getName() << " of function " << FunctionName << " in " << SourceFileName << "\n";
+ }
+ }
+
// Only initialize a __block's storage: we always initialize the header.
if (emission.IsEscapingByRef && !locIsByrefHeader)
Loc = emitBlockByrefAddress(Loc, &D, /*follow=*/false);
Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ 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<f_Group>,
+ Flags<[CC1Option, CoreOption]>, HelpText<"Stop initializing trivial automatic stack variables after the specified number of instances">;
def fstandalone_debug : Flag<["-"], "fstandalone-debug">, Group<f_Group>, Flags<[CoreOption]>,
HelpText<"Emit full debug info for all types used by the program">;
def fno_standalone_debug : Flag<["-"], "fno-standalone-debug">, Group<f_Group>, Flags<[CoreOption]>,
Index: clang/include/clang/Basic/LangOptions.def
===================================================================
--- clang/include/clang/Basic/LangOptions.def
+++ 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")
ENUM_LANGOPT(SignedOverflowBehavior, SignedOverflowBehaviorTy, 2, SOB_Undefined,
"signed integer overflow handling")
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
