Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

test tree transformations of ASTs with new checked types and bounds expressions #6

Closed
dtarditi opened this issue Jun 28, 2016 · 1 comment
Closed

test tree transformations of ASTs with new checked types and bounds expressions #6

dtarditi opened this issue Jun 28, 2016 · 1 comment
Assignees
@dtarditi
Labels
wontfix

Comments

@dtarditi
Copy link
Member

No description provided.

@dtarditi dtarditi mentioned this issue Jun 28, 2016
Merged
@dtarditi dtarditi added this to the Sprint 9 milestone Jun 28, 2016
@dtarditi dtarditi self-assigned this Jun 28, 2016
@dtarditi dtarditi removed this from the Sprint 9 milestone Jun 28, 2016
dtarditi added a commit that referenced this issue Jun 30, 2016
@dtarditi
Extend clang IR with bounds expressions and parse bounds expressions …
6d4d831 
…for parameters. (#8)

This change extends the clang IR to represent Checked C bounds expressions and optional bounds expressions for variable declarations. It also adds support for parsing bounds expressions and modifies parsing of function parameter lists to parse optional bounds expressions.

Bounds expressions are represented in the IR by adding a new abstract class BoundsExpr and subclassing it for count bounds expressions (count(e1) and byte_count(e1)), range bounds expressions (bounds(e1, e2)), and nullary bounds expressions(bounds(none)). AST printing, serialization, traversal, and tree transformations are extended handle the new expressions.

Bounds expressions are attached to variable declarations by adding an additional member to VarDecls. Many VarDecls will not have bounds expressions, so this adds extra space overhead to the representation of VarDecls. We can revisit this later if it becomes an issue.

To test the new bounds expressions, we add parsing of bounds expressions for function parameter lists and attach the parsed bounds expressions to the VarDecls for the parameters.

Bounds expressions for parameters need to be processed in a scope with all the parameters available. They are currently being processed in a scope that contains the parameters seen so far. This is a little complicated to implement in clang. You have to delay parsing of the bounds expressions. I will come back to this after getting basic parsing of bounds expressions working. I've opened issue #7 to track this.

Testing:
•This passes the current test baseline for this snapshot of clang:
•Wrote new feature tests of parsing of parameters with bounds declarations. There will be a separate pull request to the Github CheckedC repo for these tests.
•Passes the existing Checked C tests.
  Expected Passes    : 8942
  Expected Failures  : 21
  Unsupported Tests  : 206
  Unexpected Failures: 3

•We still need to test AST printing, serialization, traversal, and tree transformations. I've opened issues #4 , #3, #5, and #6 to track this.
@dtarditi dtarditi mentioned this issue Feb 10, 2017
Closed
@dtarditi dtarditi added work item This labels issues that are not exactly bugs but are about improvements. and removed enhancement labels Mar 17, 2017
@dtarditi dtarditi added wontfix and removed work item This labels issues that are not exactly bugs but are about improvements. labels Sep 20, 2017
@dtarditi
Copy link
Member Author

There aren't tests for this in clang because it is difficult to test. Instead, it is tested indirectly by using it within clang. We are using the AST rewriting templates enough we can rely on indirect testing too.

@AnnaKornfeldSimpson AnnaKornfeldSimpson mentioned this issue Jul 13, 2018
Closed
mgrang pushed a commit that referenced this issue Feb 18, 2020
@jasonmolenda
Add support to ProcessMachCore::DoLoadCore to handle an EFI UUID str.
be4be61 
If a core file has an EFI version string which includes a UUID
(similar to what it returns for the kdp KDP_KERNELVERSION packet)
in the LC_IDENT or LC_NOTE 'kern ver str' load command.  In that
case, we should try to find the binary and dSYM for the UUID
listed.  The dSYM may have python code which knows how to relocate
the binary to the correct address in lldb's target section load
list and loads other ancillary binaries.

The test case is a little involved,

1. it compiles an inferior hello world apple (a.out),
2. it compiles a program which can create a corefile manually
   with a specific binary's UUID encoded in it,
3. it gets the UUID of the a.out binary,
4. it creates a shell script, dsym-for-uuid.sh, which will
   return the full path to the a.out + a.out.dSYM when called
   with teh correct UUID,
5. it sets the LLDB_APPLE_DSYMFORUUID_EXECUTABLE env var before
   creating the lldb target, to point to this dsym-for-uuid.sh,
6. runs the create-corefile binary we compiled in step #2,
7. loads the corefile from step #6 into lldb,
8. verifies that lldb loaded a.out by reading the LC_NOTE
   load command from the corefile, calling dsym-for-uuid.sh with
   that UUID, got back the path to a.out and loaded it.

whew!

<rdar://problem/47562911>

llvm-svn: 366378
kkjeer pushed a commit that referenced this issue Sep 23, 2020
@DimitryAndric @zmodem
Instantiate Error in Target::GetEntryPointAddress() only when necessary
6406b6f 
When `Target::GetEntryPointAddress()` calls `exe_module->GetObjectFile()->GetEntryPointAddress()`, and the returned
`entry_addr` is valid, it can immediately be returned.

However, just before that, an `llvm::Error` value has been setup, but in this case it is not consumed before returning, like is done further below in the function.

In https://bugs.freebsd.org/248745 we got a bug report for this, where a very simple test case aborts and dumps core:

```
* thread #1, name = 'testcase', stop reason = breakpoint 1.1
    frame #0: 0x00000000002018d4 testcase`main(argc=1, argv=0x00007fffffffea18) at testcase.c:3:5
   1	int main(int argc, char *argv[])
   2	{
-> 3	    return 0;
   4	}
(lldb) p argc
Program aborted due to an unhandled Error:
Error value was Success. (Note: Success values must still be checked prior to being destroyed).

Thread 1 received signal SIGABRT, Aborted.
thr_kill () at thr_kill.S:3
3	thr_kill.S: No such file or directory.
(gdb) bt
#0  thr_kill () at thr_kill.S:3
#1  0x00000008049a0004 in __raise (s=6) at /usr/src/lib/libc/gen/raise.c:52
#2  0x0000000804916229 in abort () at /usr/src/lib/libc/stdlib/abort.c:67
#3  0x000000000451b5f5 in fatalUncheckedError () at /usr/src/contrib/llvm-project/llvm/lib/Support/Error.cpp:112
#4  0x00000000019cf008 in GetEntryPointAddress () at /usr/src/contrib/llvm-project/llvm/include/llvm/Support/Error.h:267
#5  0x0000000001bccbd8 in ConstructorSetup () at /usr/src/contrib/llvm-project/lldb/source/Target/ThreadPlanCallFunction.cpp:67
#6  0x0000000001bcd2c0 in ThreadPlanCallFunction () at /usr/src/contrib/llvm-project/lldb/source/Target/ThreadPlanCallFunction.cpp:114
#7  0x00000000020076d4 in InferiorCallMmap () at /usr/src/contrib/llvm-project/lldb/source/Plugins/Process/Utility/InferiorCallPOSIX.cpp:97
#8  0x0000000001f4be33 in DoAllocateMemory () at /usr/src/contrib/llvm-project/lldb/source/Plugins/Process/FreeBSD/ProcessFreeBSD.cpp:604
#9  0x0000000001fe51b9 in AllocatePage () at /usr/src/contrib/llvm-project/lldb/source/Target/Memory.cpp:347
#10 0x0000000001fe5385 in AllocateMemory () at /usr/src/contrib/llvm-project/lldb/source/Target/Memory.cpp:383
#11 0x0000000001974da2 in AllocateMemory () at /usr/src/contrib/llvm-project/lldb/source/Target/Process.cpp:2301
#12 CanJIT () at /usr/src/contrib/llvm-project/lldb/source/Target/Process.cpp:2331
#13 0x0000000001a1bf3d in Evaluate () at /usr/src/contrib/llvm-project/lldb/source/Expression/UserExpression.cpp:190
#14 0x00000000019ce7a2 in EvaluateExpression () at /usr/src/contrib/llvm-project/lldb/source/Target/Target.cpp:2372
#15 0x0000000001ad784c in EvaluateExpression () at /usr/src/contrib/llvm-project/lldb/source/Commands/CommandObjectExpression.cpp:414
#16 0x0000000001ad86ae in DoExecute () at /usr/src/contrib/llvm-project/lldb/source/Commands/CommandObjectExpression.cpp:646
#17 0x0000000001a5e3ed in Execute () at /usr/src/contrib/llvm-project/lldb/source/Interpreter/CommandObject.cpp:1003
#18 0x0000000001a6c4a3 in HandleCommand () at /usr/src/contrib/llvm-project/lldb/source/Interpreter/CommandInterpreter.cpp:1762
#19 0x0000000001a6f98c in IOHandlerInputComplete () at /usr/src/contrib/llvm-project/lldb/source/Interpreter/CommandInterpreter.cpp:2760
#20 0x0000000001a90b08 in Run () at /usr/src/contrib/llvm-project/lldb/source/Core/IOHandler.cpp:548
#21 0x00000000019a6c6a in ExecuteIOHandlers () at /usr/src/contrib/llvm-project/lldb/source/Core/Debugger.cpp:903
#22 0x0000000001a70337 in RunCommandInterpreter () at /usr/src/contrib/llvm-project/lldb/source/Interpreter/CommandInterpreter.cpp:2946
#23 0x0000000001d9d812 in RunCommandInterpreter () at /usr/src/contrib/llvm-project/lldb/source/API/SBDebugger.cpp:1169
#24 0x0000000001918be8 in MainLoop () at /usr/src/contrib/llvm-project/lldb/tools/driver/Driver.cpp:675
#25 0x000000000191a114 in main () at /usr/src/contrib/llvm-project/lldb/tools/driver/Driver.cpp:890```

Fix the incorrect error catch by only instantiating an `Error` object if it is necessary.

Reviewed By: JDevlieghere

Differential Revision: https://reviews.llvm.org/D86355

(cherry picked from commit 1ce07cd)
dopelsunce pushed a commit to dopelsunce/checkedc-clang that referenced this issue Sep 28, 2020
@dtarditi
Merge pull request checkedc#6 from dtarditi/master
573c8a1 
Revamp discussion of implicit conversions involving safe pointers
@sulekhark sulekhark mentioned this issue Apr 13, 2021
Closed
sulekhark pushed a commit that referenced this issue Jul 21, 2021
@yonghong-song @tstellar
BPF: Fix a bug in peephole TRUNC elimination optimization
6564e0c 
Andrei Matei reported a llvm11 core dump for his bpf program
   https://bugs.llvm.org/show_bug.cgi?id=48578
The core dump happens in LiveVariables analysis phase.
  #4 0x00007fce54356bb0 __restore_rt
  #5 0x00007fce4d51785e llvm::LiveVariables::HandleVirtRegUse(unsigned int,
      llvm::MachineBasicBlock*, llvm::MachineInstr&)
  #6 0x00007fce4d519abe llvm::LiveVariables::runOnInstr(llvm::MachineInstr&,
      llvm::SmallVectorImpl<unsigned int>&)
  #7 0x00007fce4d519ec6 llvm::LiveVariables::runOnBlock(llvm::MachineBasicBlock*, unsigned int)
  #8 0x00007fce4d51a4bf llvm::LiveVariables::runOnMachineFunction(llvm::MachineFunction&)
The bug can be reproduced with llvm12 and latest trunk as well.

Futher analysis shows that there is a bug in BPF peephole
TRUNC elimination optimization, which tries to remove
unnecessary TRUNC operations (a <<= 32; a >>= 32).
Specifically, the compiler did wrong transformation for the
following patterns:
   %1 = LDW ...
   %2 = SLL_ri %1, 32
   %3 = SRL_ri %2, 32
   ... %3 ...
   %4 = SRA_ri %2, 32
   ... %4 ...

The current transformation did not check how many uses of %2
and did transformation like
   %1 = LDW ...
   ... %1 ...
   %4 = SRL_ri %2, 32
   ... %4 ...
and pseudo register %2 is used by not defined and
caused LiveVariables analysis core dump.

To fix the issue, when traversing back from SRL_ri to SLL_ri,
check to ensure SLL_ri has only one use. Otherwise, don't
do transformation.

Differential Revision: https://reviews.llvm.org/D97792

(cherry picked from commit 51cdb78)
@secure-sw-dev-bot secure-sw-dev-bot mentioned this issue Jan 16, 2022
Closed
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Assignees

@dtarditi dtarditi

Labels
wontfix
Projects
None yet
Milestone
No milestone
Development

No branches or pull requests
1 participant
@dtarditi