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Make PrettyStackTraceEntry use ManagedStatic for its ThreadLocal.

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This was somewhat tricky because ~PrettyStackTraceEntry() may run after 
llvm_shutdown() has been called. This is rare and only happens for a common idiom 
used in the main() functions of command-line tools. This works around the idiom by 
skipping the stack clean-up if the PrettyStackTraceHead ManagedStatic is not 
constructed (i.e. llvm_shutdown() has been called).



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190730 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Filip Pizlo 2013-09-13 22:59:47 +00:00
parent 98bae99266
commit e94e0984df
2 changed files with 20 additions and 9 deletions
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1
include/llvm/Support/ManagedStatic.h
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@ -99,7 +99,6 @@ public:
/// llvm_shutdown - Deallocate and destroy all ManagedStatic variables.
void llvm_shutdown();
/// llvm_shutdown_obj - This is a simple helper class that calls
/// llvm_shutdown() when it is destroyed.
struct llvm_shutdown_obj {

28
lib/Support/PrettyStackTrace.cpp
View File

@ -15,6 +15,7 @@
#include "llvm/Support/PrettyStackTrace.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Config/config.h" // Get autoconf configuration settings
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/ThreadLocal.h"
#include "llvm/Support/Watchdog.h"
@ -30,8 +31,7 @@ namespace llvm {
bool DisablePrettyStackTrace = false;
}
// FIXME: This should be thread local when llvm supports threads.
static sys::ThreadLocal<const PrettyStackTraceEntry> PrettyStackTraceHead;
static ManagedStatic<sys::ThreadLocal<const PrettyStackTraceEntry> > PrettyStackTraceHead;
static unsigned PrintStack(const PrettyStackTraceEntry *Entry, raw_ostream &OS){
unsigned NextID = 0;
@ -49,12 +49,12 @@ static unsigned PrintStack(const PrettyStackTraceEntry *Entry, raw_ostream &OS){
/// PrintCurStackTrace - Print the current stack trace to the specified stream.
static void PrintCurStackTrace(raw_ostream &OS) {
// Don't print an empty trace.
if (PrettyStackTraceHead.get() == 0) return;
if (PrettyStackTraceHead->get() == 0) return;
// If there are pretty stack frames registered, walk and emit them.
OS << "Stack dump:\n";
PrintStack(PrettyStackTraceHead.get(), OS);
PrintStack(PrettyStackTraceHead->get(), OS);
OS.flush();
}
@ -114,14 +114,26 @@ PrettyStackTraceEntry::PrettyStackTraceEntry() {
(void)HandlerRegistered;
// Link ourselves.
NextEntry = PrettyStackTraceHead.get();
PrettyStackTraceHead.set(this);
NextEntry = PrettyStackTraceHead->get();
PrettyStackTraceHead->set(this);
}
PrettyStackTraceEntry::~PrettyStackTraceEntry() {
assert(PrettyStackTraceHead.get() == this &&
// Do nothing if PrettyStackTraceHead is uninitialized. This can only happen
// if a shutdown occurred after we created the PrettyStackTraceEntry. That
// does occur in the following idiom:
//
// PrettyStackTraceProgram X(...);
// llvm_shutdown_obj Y;
//
// Without this check, we may end up removing ourselves from the stack trace
// after PrettyStackTraceHead has already been destroyed.
if (!PrettyStackTraceHead.isConstructed())
return;
assert(PrettyStackTraceHead->get() == this &&
"Pretty stack trace entry destruction is out of order");
PrettyStackTraceHead.set(getNextEntry());
PrettyStackTraceHead->set(getNextEntry());
}
void PrettyStackTraceString::print(raw_ostream &OS) const {