Bug 249490

Summary: dwfl_module_addrsym misses nested symbols
Product: [Fedora] Fedora Reporter: Andrew Cagney <cagney>
Component: elfutilsAssignee: Roland McGrath <roland>
Status: CLOSED ERRATA QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: low Docs Contact:
Priority: low    
Version: 7   
Target Milestone: ---   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: 0.129-1.fc7 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2007-08-29 17:30:50 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 173278    
Attachments:
Description Flags
Candidate fix none

Description Andrew Cagney 2007-07-25 01:37:26 UTC
1) testGlobalAfterNested(frysk.rt.TestSymbol)junit.framework.ComparisonFailure:
symbol global_outer expected:<global_outer> but was:<local_st_size_0>
  at frysk.rt.TestSymbol.symbolTest(TestRunner)
  at frysk.rt.TestSymbol.testGlobalAfterNested(TestRunner)
  at frysk.junit.Runner.runCases(TestRunner)
  at frysk.junit.Runner.runArchCases(TestRunner)
  at frysk.junit.Runner.runTestCases(TestRunner)
  at TestRunner.main(TestRunner)
2) testLocalAfterNested(frysk.rt.TestSymbol)junit.framework.ComparisonFailure:
symbol local_outer expected:<...outer> but was:<...st_size_0>
  at frysk.rt.TestSymbol.symbolTest(TestRunner)
  at frysk.rt.TestSymbol.testLocalAfterNested(TestRunner)
  at frysk.junit.Runner.runCases(TestRunner)
  at frysk.junit.Runner.runArchCases(TestRunner)
  at frysk.junit.Runner.runTestCases(TestRunner)
  at TestRunner.main(TestRunner)

These two are effectively the same.  The layout is:

   local_st_size_0: // this symbol has no size

   global_outer:
       nop
       local_in_global:
         nop
         .size local_in_global, .-local_in_global
      nop
      <<you-are-here>>
      .size global_outer, .-global_outer

that is global_outer contains a nested symbol but the "pc" is beyond that back
in the outer/global symbol.

I'm guessing that "global_outer" should be returned.  Currently local_st_size_0
is returned :-(


3)
testNoSymbolAfterGlobal(frysk.rt.TestSymbol)junit.framework.ComparisonFailure:
symbol [unknown] expected:<[unknown]> but was:<local_st_size_0>
  at frysk.rt.TestSymbol.symbolTest(TestRunner)
  at frysk.rt.TestSymbol.testNoSymbolAfterGlobal(TestRunner)
  at frysk.junit.Runner.runCases(TestRunner)
  at frysk.junit.Runner.runArchCases(TestRunner)
  at frysk.junit.Runner.runTestCases(TestRunner)
  at TestRunner.main(TestRunner)
4) testNoSymbolAfterLocal(frysk.rt.TestSymbol)junit.framework.ComparisonFailure:
symbol [unknown] expected:<[unknown]> but was:<local_st_size_0>
  at frysk.rt.TestSymbol.symbolTest(TestRunner)
  at frysk.rt.TestSymbol.testNoSymbolAfterLocal(TestRunner)
  at frysk.junit.Runner.runCases(TestRunner)
  at frysk.junit.Runner.runArchCases(TestRunner)
  at frysk.junit.Runner.runTestCases(TestRunner)
  at TestRunner.main(TestRunner)

This is the no-symbol case, there is a hole in the memory where there is no
valid symbol vis:

   local_st_size_0: // this symbol has no size

   global_symbol:
      nop
      nop
      .size global_symbol, .-global_symbol

   << you are here >>

I'm guessing it should not get a symbol at all (the [unknown]).  It currently
gets the nearest unsized symbol.

5)
testGlobalSize0InGlobal(frysk.rt.TestSymbol)junit.framework.ComparisonFailure:
symbol global_0_in_global expected:<...0_in_global> but was:<...after_0>
  at frysk.rt.TestSymbol.symbolTest(TestRunner)
  at frysk.rt.TestSymbol.testGlobalSize0InGlobal(TestRunner)
  at frysk.junit.Runner.runCases(TestRunner)
  at frysk.junit.Runner.runArchCases(TestRunner)
  at frysk.junit.Runner.runTestCases(TestRunner)
  at TestRunner.main(TestRunner)
6) testLocalSize0InGlobal(frysk.rt.TestSymbol)junit.framework.ComparisonFailure:
symbol local_0_in_global expected:<local_0_in_global> but was:<global_after_0>
  at frysk.rt.TestSymbol.symbolTest(TestRunner)
  at frysk.rt.TestSymbol.testLocalSize0InGlobal(TestRunner)
  at frysk.junit.Runner.runCases(TestRunner)
  at frysk.junit.Runner.runArchCases(TestRunner)
  at frysk.junit.Runner.runTestCases(TestRunner)
  at TestRunner.main(TestRunner)
7) testGlobalSize0InLocal(frysk.rt.TestSymbol)junit.framework.ComparisonFailure:
symbol global_0_in_local expected:<global_0_in_local> but was:<local_after_0>
  at frysk.rt.TestSymbol.symbolTest(TestRunner)
  at frysk.rt.TestSymbol.testGlobalSize0InLocal(TestRunner)
  at frysk.junit.Runner.runCases(TestRunner)
  at frysk.junit.Runner.runArchCases(TestRunner)
  at frysk.junit.Runner.runTestCases(TestRunner)
  at TestRunner.main(TestRunner)
8) testLocalSize0InLocal(frysk.rt.TestSymbol)junit.framework.ComparisonFailure:
symbol local_0_in_local expected:<...0_in_local> but was:<...after_0>
  at frysk.rt.TestSymbol.symbolTest(TestRunner)
  at frysk.rt.TestSymbol.testLocalSize0InLocal(TestRunner)
  at frysk.junit.Runner.runCases(TestRunner)
  at frysk.junit.Runner.runArchCases(TestRunner)
  at frysk.junit.Runner.runTestCases(TestRunner)
  at TestRunner.main(TestRunner)

These are cases where there is a nested symbol within a sized symbol vis:

   global_after_0:
      nop
      local_0_in_global:
         << you are here >>
      nop
      .size global_after_0, .-global_after_0

here, since the PC is exactly at the unsized local symbol I'm guessing that it
should return that.  It currently gets the containing sized symbol.

Comment 1 Andrew Cagney 2007-07-26 17:02:09 UTC
Created attachment 160041 [details]
Candidate fix

Ignore the printf's :-)

Comment 2 Andrew Cagney 2007-07-26 22:56:36 UTC
This gives a better fuzzy match.  Notice how it looks at the symbol's end, not
start.  If this matches a sized symbol it is later discarded.

	  /* Save the symbol which is "closer".  Use the end-address
	     so that a sized symbol that ends closer to an unsized
	     symbol wins (unsized symbols are typically created using
	     hand-written assembler).  */
	  if (sym.st_value + sym.st_size
	      >= closest_sym->st_value + closest_sym->st_size
	      && same_section (&sym, shndx))
	    {
	      closest ();
	      continue;
	    }
	}

Comment 3 Fedora Update System 2007-08-20 16:01:03 UTC
elfutils-0.129-1.fc7 has been pushed to the Fedora 7 testing repository.  If problems still persist, please make note of it in this bug report.

Comment 4 Fedora Update System 2007-08-29 17:30:44 UTC
elfutils-0.129-1.fc7 has been pushed to the Fedora 7 stable repository.  If problems still persist, please make note of it in this bug report.