[clang] 2a06850 - [-Wcompletion-handler] Fix a non-termination issue (#78380)
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Fri Jan 26 11:23:19 PST 2024
Author: Ziqing Luo
Date: 2024-01-26T11:23:15-08:00
New Revision: 2a068507016e476893b6b1b9c55b255dbae5829e
URL: https://github.com/llvm/llvm-project/commit/2a068507016e476893b6b1b9c55b255dbae5829e
DIFF: https://github.com/llvm/llvm-project/commit/2a068507016e476893b6b1b9c55b255dbae5829e.diff
LOG: [-Wcompletion-handler] Fix a non-termination issue (#78380)
The Called-Once dataflow analysis could never terminate as a
consequence of non-monotonic update on states. States of kind Escape
can override states leading to non-monotonic update.
This fix disallows the `Escape` state to override the `Reported`
state.
rdar://119671856
Added:
Modified:
clang/lib/Analysis/CalledOnceCheck.cpp
clang/test/SemaObjC/warn-called-once.m
Removed:
################################################################################
diff --git a/clang/lib/Analysis/CalledOnceCheck.cpp b/clang/lib/Analysis/CalledOnceCheck.cpp
index 04c5f6aa9c7450..30cbd257b65e8f 100644
--- a/clang/lib/Analysis/CalledOnceCheck.cpp
+++ b/clang/lib/Analysis/CalledOnceCheck.cpp
@@ -163,7 +163,7 @@ class ParameterStatus {
NotVisited = 0x8, /* 1000 */
// We already reported a violation and stopped tracking calls for this
// parameter.
- Reported = 0x15, /* 1111 */
+ Reported = 0xF, /* 1111 */
LLVM_MARK_AS_BITMASK_ENUM(/* LargestValue = */ Reported)
};
@@ -932,7 +932,8 @@ class CalledOnceChecker : public ConstStmtVisitor<CalledOnceChecker> {
ParameterStatus &CurrentParamStatus = CurrentState.getStatusFor(Index);
// Escape overrides whatever error we think happened.
- if (CurrentParamStatus.isErrorStatus()) {
+ if (CurrentParamStatus.isErrorStatus() &&
+ CurrentParamStatus.getKind() != ParameterStatus::Kind::Reported) {
CurrentParamStatus = ParameterStatus::Escaped;
}
}
diff --git a/clang/test/SemaObjC/warn-called-once.m b/clang/test/SemaObjC/warn-called-once.m
index dbe8dc1cf1ae17..f23e41e00ee298 100644
--- a/clang/test/SemaObjC/warn-called-once.m
+++ b/clang/test/SemaObjC/warn-called-once.m
@@ -1194,6 +1194,16 @@ - (void)test_escape_after_branch:(int)cond
escape(handler);
}
+- (void)test_termination:(int)cond
+ withCompletion:(void (^)(void))handler {
+ // The code below was able to cause non-termination but should be
+ // fixed now:
+ do {
+ escape(handler);
+ handler(); // expected-warning{{completion handler is called twice}} expected-note{{previous call is here; set to nil to indicate it cannot be called afterwards}}
+ } while (cond);
+}
+
typedef void (^DeferredBlock)(void);
static inline void DefferedCallback(DeferredBlock *inBlock) { (*inBlock)(); }
#define _DEFERCONCAT(a, b) a##b
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