Skip to content

Parse bounds declarations for function return values. #21

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.

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

Merged
merged 2 commits into from
Jul 22, 2016

Conversation

dtarditi
Copy link
Member

This extends parsing of function declarators to parse bounds expressions for
function return values. A return bounds expression is declared by following
a parameter list with ':' bounds-expression.

The return bounds information is propagated to the representation of function
declarations in clang. It is not propagated yet to function types because
there is no way to represent it in function types. I have opened issue #20
to track that and added a few TODO's to the code flagging where the
information will need to be added.

Testing:

  • Add feature tests for parsing return bounds. The tests are in
    the file return_bounds.c, which will be committed separately to the checkedc
    Github repo.
  • Passes existing clang regression test baseline.

This extends parsing of function declarators to parse bounds expressions for
function return values.  A return bounds expression is declared by following
a parameter list with ':' bounds-expression.

The return bounds information is propagated to the representation of function
declarations in clang.  It is not propagated yet to function types because
there is no way to represent it in function types.  I have opened issue checkedc#20
to track taht and added a few TODO's to the code code flagging where the
information will need to be added.

Testing:
- Add feature tests for parsing return bounds.  The tests are in in
the file return_bounds.c, which will be committed separately to the checkedc
Github repo.
- Passes existing clang regression test baseline.
@msftclas
Copy link

Hi @dtarditi, I'm your friendly neighborhood Microsoft Pull Request Bot (You can call me MSBOT). Thanks for your contribution!


It looks like you're a Microsoft contributor (David Tarditi). If you're full-time, we DON'T require a Contribution License Agreement. If you are a vendor, please DO sign the electronic Contribution License Agreement. It will take 2 minutes and there's no faxing! https://cla.microsoft.com.

TTYL, MSBOT;

@@ -1287,11 +1287,18 @@ struct DeclaratorChunk {
/// \brief The end location of the exception specification, if any.
unsigned ExceptionSpecLocEnd;

/// The location of the ':' for the return bounds expression in the source
unsigned ReturnBoundsColon;
Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

ReturnBoundsColon [](start = 13, length = 17)

[Nit] I'd suggest including 'Loc' in the name to make it clear that this is a location.

@reubeno
Copy link

reubeno commented Jul 20, 2016

I called out a few very low-priority suggestions; otherwise, looks great.

@awruef
Copy link
Collaborator

awruef commented Jul 20, 2016

Looks good to me.

This change addresses code review feedback to rename some variables and add
a comment.

It also improves the error message for bounds(a,b) when a and b are omitted.
We would get two error messages at the same location, one saying that an
expression was expected and the other saying that a ',' was expected.  The
improvement is to print the error message for the ',' only if nothing
went wrong trying to parse the lower bound.
@dtarditi dtarditi merged commit 6645f0d into checkedc:master Jul 22, 2016
@dtarditi dtarditi deleted the issue15 branch July 29, 2016 20:16
kkjeer pushed a commit that referenced this pull request Sep 23, 2020
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 pull request Sep 28, 2020
Clarify some parts of bounds declaration checking.
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Projects
None yet
Development

Successfully merging this pull request may close these issues.

5 participants