[PATCH] D87656: [llvm-dwarfdump] --show-sources option to show all sources

[James Henderson via Phabricator via llvm-commits]

jhenderson added inline comments.


================
Comment at: llvm/tools/llvm-dwarfdump/llvm-dwarfdump.cpp:455
+  for (const auto &CU : DICtx.compile_units()) {
+    const auto *LT = DICtx.getLineTableForUnit(CU.get());
+    for (uint32_t I = 1; I <= LT->Prologue.FileNames.size(); ++I) {
----------------
Higuoxing wrote:
> jhenderson wrote:
> > I think we need testing for multiple CUs. The current test only checks a single one. This might go against the yaml2obj usage suggested above though (@Higuoxing, is there support for multiple tables in .debug_line yet?).
> > is there support for multiple tables in .debug_line yet?
> 
> Yes, `yaml2obj` supports emitting multiple line tables. I'm able to help craft these test cases.
> 
> ----------------------------
> 
> It looks that `LT` isn't checked. If a compilation unit doesn't have an associated line table, `llvm-dwarfdump --show-sources` will crash.
> 
> ```
> const auto *LT = DICtx.getLineTableForUnit(CU.get()); // Can be a null pointer.
> for (uint32_t I = 1; I <= LT->Prologue.FileNames.size(); ++I) {
>                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>   ...
> }
> ```
> 
> We can reproduce it using the following test case.
> 
> ```
> $ yaml2obj %s | llvm-dwarfdump --show-sources -
> ```
> 
> ```
> --- !ELF
> FileHeader:
>   Class:   ELFCLASS64
>   Data:    ELFDATA2LSB
>   Type:    ET_EXEC
>   Machine: EM_X86_64
> DWARF:
>   debug_info:
>     - Version: 4
> ```
Nice catch! In fact, do we really need to use the CUs at all for this? Could we not just iterate over all line tables? That would allow this to work when there is no .debug_info data too (which the DWARF spec implies is permitted).


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D87656/new/

https://reviews.llvm.org/D87656