whisperity added a reviewer: whisperity.
whisperity added a comment.
Herald added a subscriber: rnkovacs.
This generally looks good, and thank you! I have a few minor comments (mostly
presentation and documentation).
================
Comment at: clang-tools-extra/clang-tidy/bugprone/SignalHandlerCheck.cpp:72-73
/// Given a call graph node of a function and another one that is called from
/// this function, get a CallExpr of the corresponding function call.
/// It is unspecified which call is found if multiple calls exist, but the
order
----------------
(Nit: There are a lot of indirections in the documentation that did not help
understanding what is happening here.)
================
Comment at: clang-tools-extra/clang-tidy/bugprone/SignalHandlerCheck.cpp:159-160
Itr != ItrE; ++Itr) {
const auto *CallF = dyn_cast<FunctionDecl>((*Itr)->getDecl());
- if (CallF && !isFunctionAsyncSafe(CallF)) {
- assert(Itr.getPathLength() >= 2);
- reportBug(CallF, findCallExpr(Itr.getPath(Itr.getPathLength() - 2),
*Itr),
- /*DirectHandler=*/false);
- reportHandlerCommon(Itr, SignalCall, HandlerDecl, HandlerExpr);
+ if (CallF) {
+ unsigned int PathL = Itr.getPathLength();
----------------
================
Comment at: clang-tools-extra/clang-tidy/bugprone/SignalHandlerCheck.cpp:165-171
+ if (checkFunction(CallF, CallOrRef))
+ reportHandlerChain(Itr, HandlerExpr);
}
}
}
+bool SignalHandlerCheck::checkFunction(const FunctionDecl *FD,
----------------
What does the return value of `checkFunction` signal to the user, and the `if`?
================
Comment at: clang-tools-extra/clang-tidy/bugprone/SignalHandlerCheck.cpp:188
+ if (!FD->hasBody()) {
+ diag(CallOrRef->getBeginLoc(), "cannot verify if external function %0 is "
+ "asynchronous-safe; "
----------------
================
Comment at: clang-tools-extra/clang-tidy/bugprone/SignalHandlerCheck.cpp:239
//
https://wiki.sei.cmu.edu/confluence/display/c/SIG30-C.+Call+only+asynchronous-safe+functions+within+signal+handlers
-llvm::StringSet<> SignalHandlerCheck::MinimalConformingFunctions{
+const llvm::StringSet<> SignalHandlerCheck::MinimalConformingFunctions{
"signal", "abort", "_Exit", "quick_exit"};
----------------
whisperity wrote:
> Perchance this could work with `constexpr`? Although I'm not sure how widely
> supported that is, given that we're pegged at C++14 still.
Otherwise, **if** these are truly const and we are reasonably sure they can be
instantiated on any meaningful system without crashing, then these could be a
TU-`static`. It's still iffy, but that technique is used in many places already.
================
Comment at: clang-tools-extra/clang-tidy/bugprone/SignalHandlerCheck.cpp:239-240
//
https://wiki.sei.cmu.edu/confluence/display/c/SIG30-C.+Call+only+asynchronous-safe+functions+within+signal+handlers
-llvm::StringSet<> SignalHandlerCheck::MinimalConformingFunctions{
+const llvm::StringSet<> SignalHandlerCheck::MinimalConformingFunctions{
"signal", "abort", "_Exit", "quick_exit"};
----------------
Perchance this could work with `constexpr`? Although I'm not sure how widely
supported that is, given that we're pegged at C++14 still.
================
Comment at: clang-tools-extra/clang-tidy/bugprone/SignalHandlerCheck.h:48-49
bool isSystemCallAsyncSafe(const FunctionDecl *FD) const;
- void reportBug(const FunctionDecl *CalledFunction, const Expr *CallOrRef,
- bool DirectHandler);
- void reportHandlerCommon(llvm::df_iterator<clang::CallGraphNode *> Itr,
- const CallExpr *SignalCall,
- const FunctionDecl *HandlerDecl,
- const Expr *HandlerRef);
+ /// Add bug report notes to show the call chain of functions from a signal
+ /// handler to an actual called function (from it).
+ /// @param Itr Position during a call graph depth-first iteration. It
contains
----------------
First, we usually call these "diagnostics" in Tidy and not "bug report notes",
which to me seems like CSA terminology. Second... It's not clear to me what
`(from it)` is referring to. //"[...] show call chain from a signal handler to
a [... specific? provided? expected? ...] function"// sounds alright to me.
================
Comment at: clang-tools-extra/clang-tidy/bugprone/SignalHandlerCheck.h:54
+ /// @param HandlerRef Reference to the signal handler function where it is
+ /// registered (considered as first part of the call chain).
+ void reportHandlerChain(const llvm::df_iterator<clang::CallGraphNode *> &Itr,
----------------
================
Comment at: clang-tools-extra/clang-tidy/bugprone/SignalHandlerCheck.h:46-49
llvm::StringSet<> &ConformingFunctions;
static llvm::StringSet<> MinimalConformingFunctions;
static llvm::StringSet<> POSIXConformingFunctions;
----------------
njames93 wrote:
> While you're refactoring, those static StringSets really belong in the
> implementation file, and the ConformingFunctions should be a const ref.
>
> However global destructores are kind of a taboo thing, Maybe there is case to
> change them into a sorted array and binary search them to see if a function
> is conforming.
> Probably wouldn't advise using TableGens StringMatcher to build this
> functionality as that maybe a little too far.
Once the `ConformingFunctions` is const, these symbols are not needed here,
right? Static initialisation does feel dirty... (heck, there's even a CERT rule
against that too!)
================
Comment at:
clang-tools-extra/test/clang-tidy/checkers/bugprone-signal-handler-posix.c:14
printf("1234");
- // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: 'printf' may not be
asynchronous-safe; calling it from a signal handler may be dangerous
[bugprone-signal-handler]
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: system call 'printf' may not be
asynchronous-safe; calling it from a signal handler may be dangerous
[bugprone-signal-handler]
}
----------------
I'm not exactly sure we should call `printf` (and `memcpy`) a "system call". As
far as I can see, in this patch, `isSystemCall()` boils down to //"declaration
in file included as system header"//
================
Comment at:
clang-tools-extra/test/clang-tidy/checkers/bugprone-signal-handler.c:31
f_extern();
- // CHECK-NOTES: :[[@LINE-1]]:3: warning: 'f_extern' may not be
asynchronous-safe; calling it from a signal handler may be dangerous
[bugprone-signal-handler]
+ // CHECK-NOTES: :[[@LINE-1]]:3: warning: cannot verify if external function
'f_extern' is asynchronous-safe; calling it from a signal handler may be
dangerous [bugprone-signal-handler]
// CHECK-NOTES: :[[@LINE-2]]:3: note: function 'f_extern' called here from
'handler_extern'
----------------
================
Comment at:
clang-tools-extra/test/clang-tidy/checkers/bugprone-signal-handler.c:133
printf("");
// first 'printf' call (in other function) found only
}
----------------
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D118370/new/
https://reviews.llvm.org/D118370
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
