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Bug 576 - [bugpoint] JIT debugger generates really inefficient function stubs
Summary: [bugpoint] JIT debugger generates really inefficient function stubs
Status: RESOLVED FIXED
Alias: None
Product: tools
Classification: Unclassified
Component: bugpoint (show other bugs)
Version: 1.3
Hardware: All All
: P enhancement
Assignee: Chris Lattner
URL:
Keywords: quality-of-implementation
Depends on:
Blocks:
 
Reported: 2005-06-09 22:47 PDT by Chris Lattner
Modified: 2010-02-22 12:41 PST (History)
1 user (show)

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Description Chris Lattner 2005-06-09 22:47:30 PDT 
Bugpoint has to emit function stubs that call getPointerToNamedFunction to find code generated by the 
JIT.  It would be nice if it only did this the first time it was called.  Instead of emitting:

internal void %l33_main_no_exit_2E_i305_2E_i_wrapper(sbyte*, uint*) {
        %resolver = call sbyte* %getPointerToNamedFunction( sbyte* getelementptr ([30 x sbyte]* %
l33_main_no_exit_2E_i305_2E_i_name, int 0, int 0) )            ; <sbyte*> [#uses=1]
        %resolverCast = cast sbyte* %resolver to void (sbyte*, uint*)*          ; <void (sbyte*, uint*)*> 
[#uses=1]
        call void %resolverCast( sbyte* %0, uint* %0 )
        ret void
}

we would like to use something like a static var to remember this.  This should be done in 
Miscompilation.cpp:CleanupAndPrepareModules.

-Chris
Comment 1 Chris Lattner 2005-06-09 22:47:56 PDT 
Oh yeah, this would make JIT debugging like 3x faster on some programs.

:)

-Chris
Comment 2 Chris Lattner 2005-07-11 20:02:35 PDT 
This enhancement is now implemented, patch here:
http://mail.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20050711/026997.html

-Chris