[clang] c98d98b - [analyzer] Fix handle leak false positive when the handle dies too early
Gabor Horvath via cfe-commits
cfe-commits at lists.llvm.org
Mon Jan 27 09:58:48 PST 2020
Author: Gabor Horvath
Date: 2020-01-27T09:52:06-08:00
New Revision: c98d98ba9b0f917385c753becec4ddfef51bc47c
URL: https://github.com/llvm/llvm-project/commit/c98d98ba9b0f917385c753becec4ddfef51bc47c
DIFF: https://github.com/llvm/llvm-project/commit/c98d98ba9b0f917385c753becec4ddfef51bc47c.diff
LOG: [analyzer] Fix handle leak false positive when the handle dies too early
Differential Revision: https://reviews.llvm.org/D73151
Added:
Modified:
clang/lib/StaticAnalyzer/Checkers/FuchsiaHandleChecker.cpp
clang/test/Analysis/fuchsia_handle.cpp
Removed:
################################################################################
diff --git a/clang/lib/StaticAnalyzer/Checkers/FuchsiaHandleChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/FuchsiaHandleChecker.cpp
index 36d4f489214e..3a56a941ff31 100644
--- a/clang/lib/StaticAnalyzer/Checkers/FuchsiaHandleChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/FuchsiaHandleChecker.cpp
@@ -149,6 +149,10 @@ class HandleState {
CASE(Kind::Released)
CASE(Kind::Escaped)
}
+ if (ErrorSym) {
+ OS << " ErrorSym: ";
+ ErrorSym->dumpToStream(OS);
+ }
}
LLVM_DUMP_METHOD void dump() const { dump(llvm::errs()); }
@@ -401,7 +405,13 @@ void FuchsiaHandleChecker::checkDeadSymbols(SymbolReaper &SymReaper,
SmallVector<SymbolRef, 2> LeakedSyms;
HStateMapTy TrackedHandles = State->get<HStateMap>();
for (auto &CurItem : TrackedHandles) {
- if (!SymReaper.isDead(CurItem.first))
+ SymbolRef ErrorSym = CurItem.second.getErrorSym();
+ // Keeping zombie handle symbols. In case the error symbol is dying later
+ // than the handle symbol we might produce spurious leak warnings (in case
+ // we find out later from the status code that the handle allocation failed
+ // in the first place).
+ if (!SymReaper.isDead(CurItem.first) ||
+ (ErrorSym && !SymReaper.isDead(ErrorSym)))
continue;
if (CurItem.second.isAllocated() || CurItem.second.maybeAllocated())
LeakedSyms.push_back(CurItem.first);
diff --git a/clang/test/Analysis/fuchsia_handle.cpp b/clang/test/Analysis/fuchsia_handle.cpp
index ed8b695a1915..c20622be543f 100644
--- a/clang/test/Analysis/fuchsia_handle.cpp
+++ b/clang/test/Analysis/fuchsia_handle.cpp
@@ -66,6 +66,26 @@ void checkInvalidHandle2() {
zx_handle_close(sa);
}
+void handleDieBeforeErrorSymbol01() {
+ zx_handle_t sa, sb;
+ zx_status_t status = zx_channel_create(0, &sa, &sb);
+ if (status < 0)
+ return;
+ __builtin_trap();
+}
+
+void handleDieBeforeErrorSymbol02() {
+ zx_handle_t sa, sb;
+ zx_status_t status = zx_channel_create(0, &sa, &sb);
+ // expected-note at -1 {{Handle allocated through 2nd parameter}}
+ if (status == 0) { // expected-note {{Assuming 'status' is equal to 0}}
+ // expected-note at -1 {{Taking true branch}}
+ return; // expected-warning {{Potential leak of handle}}
+ // expected-note at -1 {{Potential leak of handle}}
+ }
+ __builtin_trap();
+}
+
void checkNoCrash01() {
zx_handle_t sa, sb;
zx_channel_create(0, &sa, &sb);
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