Sending async packets can deadlock a program on darwin. We currently allow breakpoint packets and memory read/write packets (for software breakpoints) to be sent while a program is running. In the GDB remote plug-in, we will interrupt the run, send the async packet and resume (currently with the continue packet that caused the program to resume). If the GDB server supports the "vCont" packet, we might have initially continued with each thread stating it should continue. If new threads show up while we are stopped, which happend when running GCD, we can end up with new threads that we aren't mentioning in the continue list. So we start with a thread list of 1,2,3 and continue:
continue thread 1, continue thread 2, continue thread 3
Now we interrupt and set a breakpoint and we actually have threads 1,2,3,4 now when we are about to resume, yet we send:
continue thread 1, continue thread 2, continue thread 3
Any thread that isn't mentioned is currently going to stay suspended. This causes the deadlock.
llvm-svn: 157439
The Hazard checker implements in-order contraints, or interlocked
resources. Ready instructions with hazards do not enter the available
queue and are not visible to other heuristics.
The major code change is the addition of SchedBoundary to encapsulate
the state at the top or bottom of the schedule, including both a
pending and available queue.
The scheduler now counts cycles in sync with the hazard checker. These
are minimum cycle counts based on known hazards.
Targets with no itinerary (x86_64) currently remain at cycle 0. To fix
this, we need to provide some maximum issue width for all targets. We
also need to add the concept of expected latency vs. minimum latency.
llvm-svn: 157427
Plus, a patch for scan-build.
* mdoc corrections
* slightly more compact output
* same license as scan-build
* DESCRIPTION describes
* Default checkers corrected & explained
* Authors credited
The patch adds support for --help-checkers. It just lists the default
checkers by recursively invoking "scan-build -h" and looking for the
magic '+' signs.
Patch by James Lowden!
llvm-svn: 157411
Where diagnostic about unfound property is not
issued in the context where a setter is looked up
in situation in which name and property name differ
in their first letter case. // rdar://11363363
llvm-svn: 157407
I'm not sure it's really worth expressing this as a range rather than 3 specific equalities, but it doesn't seem fundamentally wrong either.
llvm-svn: 157398
Bill Wendling