[lldb-dev] LLDB can't find source...but it can?

[Ted Woodward via lldb-dev]

Background - I'm working on getting LLDB to run on Hexagon Linux, built with
an LLVM toolchain. We're using libc++ and MUSL. The loader is a bit
squirrelly right now, so I've built LLDB statically.

 

I've got full source debugging in the driver, but when I step into
SBDebugger::Create, I don't have any source. I've got symbols:

(lldb) bt

* thread #1: tid = 1, 0x00114730 lldb`lldb::SBDebugger::Create(bool) + 16,
stop reason = breakpoint 2.1

  * frame #0: 0x00114730 lldb`lldb::SBDebugger::Create(bool) + 16

    frame #1: 0x000001dc lldb`Driver::Driver(this=0x7ffefc50) + 124 at
Driver.cpp:150

    frame #2: 0x00006aa0 lldb`main(argc=1, argv=0x7ffefd34) + 240 at
Driver.cpp:1350

    frame #3: 0x04744384 lldb`__libc_start_main + 48

 

list SBDebugger::Create fails, but list SBDebugger::Create(bool) gives me
source.

(lldb) list SBDebugger::Create

(lldb) list SBDebugger::Create(bool)

File:
\local\mnt\workspace\ted\linux\llvm\tools\lldb\source\API\SBDebugger.cpp

   172      return SBDebugger::Create(false, nullptr, nullptr);

   173  }

   174

   175  SBDebugger

   176  SBDebugger::Create(bool source_init_files)

   177  {

   178      return SBDebugger::Create (source_init_files, nullptr, nullptr);

   179  }

   180

   181  SBDebugger

   182  SBDebugger::Create(bool source_init_files, lldb::LogOutputCallback
callback, void *baton)

   183

 

Finally, I try to list based on the address of the function:

(lldb) list 0x114720

error: address resolves to lldb[0x0000000000114720], but there is no line
table information available for this address.

 

But there is line table information for 0x114720 (from llvm-dwarfdump):

0x0000000000114720    177      0     80   0             0  is_stmt

0x0000000000114730    178     32     80   0             0  is_stmt
prologue_end

0x0000000000114734    178     12     80   0             0 

0x0000000000114754    178      5     80   0             0

 

 

 

My breakpoint at SBDebugger::Create resolved to prologue_end:

(lldb) break list

Current breakpoints:

1: name = 'main', locations = 1, resolved = 1, hit count = 1

  1.1: where = lldb`main + 32 at Driver.cpp:1335, address = 0x000069d0,
resolved, hit count = 1

 

2: name = 'SBDebugger::Create', locations = 3, resolved = 3, hit count = 1

  2.1: where = lldb`lldb::SBDebugger::Create(bool) + 16, address =
0x00114730, resolved, hit count = 1

  2.2: where = lldb`lldb::SBDebugger::Create() + 8, address = 0x001143c0,
resolved, hit count = 0

  2.3: where = lldb`lldb::SBDebugger::Create(bool, void (*)(char const*,
void*), void*) + 40, address = 0x00114404, resolved, hit count = 0

 

 

So - why can LLDB find the source when I specify the function explicitly, or
find the line table info when I set a breakpoint, but not when I am in the
function or list an address?

 

 

Ted

 

--

Qualcomm Innovation Center, Inc.

The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a
Linux Foundation Collaborative Project

 

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