[llvm] r233207 - Linker: Rewrite dwarfdump checks from r233164

David Blaikie dblaikie at gmail.com
Wed Mar 25 14:46:09 PDT 2015


On Wed, Mar 25, 2015 at 2:41 PM, Duncan P. N. Exon Smith <
dexonsmith at apple.com> wrote:

>
> > On 2015-Mar-25, at 14:20, David Blaikie <dblaikie at gmail.com> wrote:
> >
> >
> >
> > On Wed, Mar 25, 2015 at 2:14 PM, Duncan P. N. Exon Smith <
> dexonsmith at apple.com> wrote:
> >
> > > On 2015-Mar-25, at 14:11, David Blaikie <dblaikie at gmail.com> wrote:
> > >
> > >
> > >
> > > On Wed, Mar 25, 2015 at 2:08 PM, Duncan P. N. Exon Smith <
> dexonsmith at apple.com> wrote:
> > >
> > > > On 2015-Mar-25, at 13:06, David Blaikie <dblaikie at gmail.com> wrote:
> > > >
> > > >
> > > >
> > > > On Wed, Mar 25, 2015 at 12:57 PM, Duncan P. N. Exon Smith <
> dexonsmith at apple.com> wrote:
> > > > Author: dexonsmith
> > > > Date: Wed Mar 25 14:57:42 2015
> > > > New Revision: 233207
> > > >
> > > > URL: http://llvm.org/viewvc/llvm-project?rev=233207&view=rev
> > > > Log:
> > > > Linker: Rewrite dwarfdump checks from r233164
> > > >
> > > > Rewrite the checks from r233164 that I temporarily disabled in
> r233165.
> > > >
> > > > It turns out that the line-tables only debug info we emit from `llc`
> is
> > > > (intentionally) different on Linux than on Darwin.
> > > >
> > > > Does this need to test gmlt rather than normal -g?
> > >
> > > I suppose not, but it's easier to hand-write line-tables only debug
> info,
> >
> > Really?!  I had assumed the backend required more fidelity or details or
> > something when not in `-gmlt` mode.  I'll play around.
> >
> > Nah - in fact there was no backend option for gmlt until Eric added it
> to avoid emitting aranges, I think? Prior to that it was purely a frontend
> feature that just skipped creating the metadata for types, parameters,
> variables, etc.
> >
> > Then I used the flag Eric added to make the gmlt even smarter in the
> backend (by omitting unused subprograms, omitting unnecessary attributes,
> etc).
>
> Awesome.  Hopefully finally finished with this blasted testcase with
> r233221, which tests the debug info directly rather than relying on
> links to the line table.  I left in checks of the line table itself
> since we care about that as well, but they're no longer codependent.
>

Shiny - I haven't looked at the test case in any detail, but glad to help
get it sorted. Sounds like you've got it all squared away.


>
> >
> >
> > >
> > > You can create minimal debug inof by hand without making it "gmlt"
> debug info - don't set that gmlt flag on the CU and it shouldn't do the
> magical "minimal subprogram" thing on non-darwin anymore.
> > >
> > > and that should be sufficient for checking if the correct subprogram is
> > > around.
> > >
> > > >
> > > > If it does need to test gmlt, which bits of it does it need to test?
> Is the functionality you want to test actually used in both Darwin and
> non-Darwin, or is it only under the non-Darwin "skip unnecessary
> subprogram" stuff I implemented? (in which cas running the test on Darwin
> doesn't actually tell you anything about whether the functionality is
> working - so it might be more suitable to use a fixed triple?)
> > >
> > > I want to test:
> > >
> > >  1. That the merged IR zeros out Functions (although I imagine this
> could
> > >     change eventually).
> > >  2. That `llc` doesn't crash.
> > >  3. That in the output DWARF, the debug info from the `weak` version of
> > >     `@foo` is what's actually used (not the debug info from the
> discarded
> > >     `linkonce` version of `@foo`).
> > >
> > > All these things should be true for both Linux and Darwin (and any
> other
> > > platform we support, I think).
> > >
> > > >
> > > > r218129 started
> > > > skipping emission of subprograms with no inlined subroutines, and
> > > > r218702 was a spiritual revert of that behaviour for Darwin.
> > > >
> > > > I think we can still test this in a platform-neutral way.
> > > >
> > > >   - Stop checking for the possibly missing `DW_TAG_subprogram`
> defining
> > > >     the debug info for the real version of `@foo`.
> > > >   - Start checking the line tables, ensuring that the right debug
> info
> > > >     was used to generate them (grabbing `DW_AT_low_pc` from the
> compile
> > > >     unit).
> > > >   - I changed up the line numbers used in the "weak" version so it's
> > > >     easier to follow.
> > > >
> > > > This should hopefully finish off PR22792.
> > > >
> > > > Modified:
> > > >     llvm/trunk/test/Linker/Inputs/subprogram-linkonce-weak.ll
> > > >     llvm/trunk/test/Linker/subprogram-linkonce-weak.ll
> > > >
> > > > Modified: llvm/trunk/test/Linker/Inputs/subprogram-linkonce-weak.ll
> > > > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Linker/Inputs/subprogram-linkonce-weak.ll?rev=233207&r1=233206&r2=233207&view=diff
> > > >
> ==============================================================================
> > > > --- llvm/trunk/test/Linker/Inputs/subprogram-linkonce-weak.ll
> (original)
> > > > +++ llvm/trunk/test/Linker/Inputs/subprogram-linkonce-weak.ll Wed
> Mar 25 14:57:42 2015
> > > > @@ -1,7 +1,7 @@
> > > >  define weak i32 @foo(i32 %a, i32 %b) {
> > > >  entry:
> > > > -  %sum = call i32 @fastadd(i32 %a, i32 %b), !dbg !MDLocation(line:
> 2, scope: !3)
> > > > -  ret i32 %sum, !dbg !MDLocation(line: 3, scope: !3)
> > > > +  %sum = call i32 @fastadd(i32 %a, i32 %b), !dbg !MDLocation(line:
> 52, scope: !3)
> > > > +  ret i32 %sum, !dbg !MDLocation(line: 53, scope: !3)
> > > >  }
> > > >
> > > >  declare i32 @fastadd(i32, i32)
> > > > @@ -12,5 +12,5 @@ declare i32 @fastadd(i32, i32)
> > > >  !llvm.dbg.cu = !{!1}
> > > >  !1 = !MDCompileUnit(language: DW_LANG_C99, file: !2, subprograms:
> !{!3}, emissionKind: 2)
> > > >  !2 = !MDFile(filename: "foo.c", directory: "/path/to/dir")
> > > > -!3 = !MDSubprogram(file: !2, scope: !2, line: 1, name: "foo",
> function: i32 (i32, i32)* @foo, type: !4)
> > > > +!3 = !MDSubprogram(file: !2, scope: !2, line: 51, name: "foo",
> function: i32 (i32, i32)* @foo, type: !4)
> > > >  !4 = !MDSubroutineType(types: !{})
> > > >
> > > > Modified: llvm/trunk/test/Linker/subprogram-linkonce-weak.ll
> > > > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Linker/subprogram-linkonce-weak.ll?rev=233207&r1=233206&r2=233207&view=diff
> > > >
> ==============================================================================
> > > > --- llvm/trunk/test/Linker/subprogram-linkonce-weak.ll (original)
> > > > +++ llvm/trunk/test/Linker/subprogram-linkonce-weak.ll Wed Mar 25
> 14:57:42 2015
> > > > @@ -66,8 +66,8 @@ entry:
> > > >  ; LW: ![[FOOINBAR]] = !MDLocation(line: 2, scope: ![[FOOSP]],
> inlinedAt: ![[BARIA:[0-9]+]])
> > > >  ; LW: ![[BARIA]] = !MDLocation(line: 12, scope: ![[BARSP]])
> > > >  ; LW: ![[BARRET]] = !MDLocation(line: 13, scope: ![[BARSP]])
> > > > -; LW: ![[FOOCALL]] = !MDLocation(line: 2, scope: ![[WEAKFOOSP]])
> > > > -; LW: ![[FOORET]] = !MDLocation(line: 3, scope: ![[WEAKFOOSP]])
> > > > +; LW: ![[FOOCALL]] = !MDLocation(line: 52, scope: ![[WEAKFOOSP]])
> > > > +; LW: ![[FOORET]] = !MDLocation(line: 53, scope: ![[WEAKFOOSP]])
> > > >
> > > >  ; Same as above, but reordered.
> > > >  ; WL: ![[WCU]] = !MDCompileUnit({{.*}} subprograms: ![[WSPs:[0-9]+]]
> > > > @@ -81,8 +81,8 @@ entry:
> > > >  ; WL: ![[FOOSP]] = {{.*}}!MDSubprogram(name: "foo",
> > > >  ; Note, for symmetry, this should be "NOT: function:" and "SAME:
> ){{$}}".
> > > >  ; WL-SAME: function: i32 (i32, i32)* @foo
> > > > -; WL: ![[FOOCALL]] = !MDLocation(line: 2, scope: ![[WEAKFOOSP]])
> > > > -; WL: ![[FOORET]] = !MDLocation(line: 3, scope: ![[WEAKFOOSP]])
> > > > +; WL: ![[FOOCALL]] = !MDLocation(line: 52, scope: ![[WEAKFOOSP]])
> > > > +; WL: ![[FOORET]] = !MDLocation(line: 53, scope: ![[WEAKFOOSP]])
> > > >  ; WL: ![[FOOINBAR]] = !MDLocation(line: 2, scope: ![[FOOSP]],
> inlinedAt: ![[BARIA:[0-9]+]])
> > > >  ; WL: ![[BARIA]] = !MDLocation(line: 12, scope: ![[BARSP]])
> > > >  ; WL: ![[BARRET]] = !MDLocation(line: 13, scope: ![[BARSP]])
> > > > @@ -96,15 +96,18 @@ entry:
> > > >  ; Crasher for llc.
> > > >  ; REQUIRES: object-emission
> > > >  ; RUN: %llc_dwarf -filetype=obj -O0 %t1 -o %t1.o
> > > > -; RUNDISABLED: llvm-dwarfdump %t1.o -debug-dump=info | FileCheck %s
> -check-prefix=DWLW
> > > > +; RUN: llvm-dwarfdump %t1.o -debug-dump=all | FileCheck %s
> -check-prefix=DWLW -check-prefix=DW
> > > >  ; RUN: %llc_dwarf -filetype=obj -O0 %t2 -o %t2.o
> > > > -; RUNDISABLED: llvm-dwarfdump %t2.o -debug-dump=info | FileCheck %s
> -check-prefix=DWWL
> > > > -; Getting different dwarfdump output on different platforms, so I've
> > > > -; temporarily disabled the Dwarf FileChecks while leaving in the
> crash tests.
> > > > -; I'll keep using PR22792 to track this.
> > > > +; RUN: llvm-dwarfdump %t2.o -debug-dump=all | FileCheck %s
> -check-prefix=DWWL -check-prefix=DW
> > > > +; Don't check for the DW_TAG_subprogram for the weak version of
> @foo.  It has
> > > > +; no inlined subroutines, so with -gmlt may not exist (debuggers
> can find the
> > > > +; aranges in the compile unit and look in the line table
> directly).  See the
> > > > +; checks against the line table that follow.
> > > >
> > > > +; DW-LABEL: .debug_info contents:
> > > >  ; DWLW:     DW_TAG_compile_unit
> > > >  ; DWLW:       DW_AT_name {{.*}}"bar.c"
> > > > +; DWLW:       DW_AT_low_pc [DW_FORM_addr] ([[BARLOW:0x[0-9a-f]+]])
> > > >  ; DWLW:       DW_TAG_subprogram
> > > >  ; DWLW-NOT:     DW_AT_{{[lowhigh]*}}_pc
> > > >  ; DWLW:         DW_AT_name {{.*}}foo
> > > > @@ -117,20 +120,15 @@ entry:
> > > >  ; DWLW:           DW_AT_abstract_origin
> > > >  ; DWLW:     DW_TAG_compile_unit
> > > >  ; DWLW:       DW_AT_name {{.*}}"foo.c"
> > > > -; DWLW:       DW_TAG_subprogram
> > > > -; DWLW:         DW_AT_low_pc
> > > > -; DWLW:         DW_AT_high_pc
> > > > -; DWLW:         DW_AT_name {{.*}}foo
> > > > +; DWLW:       DW_AT_low_pc [DW_FORM_addr] ([[FOOLOW:0x[0-9a-f]+]])
> > > >
> > > >  ; The DWARF output is already symmetric (just reordered).
> > > >  ; DWWL:     DW_TAG_compile_unit
> > > >  ; DWWL:       DW_AT_name {{.*}}"foo.c"
> > > > -; DWWL:       DW_TAG_subprogram
> > > > -; DWWL:         DW_AT_low_pc
> > > > -; DWWL:         DW_AT_high_pc
> > > > -; DWWL:         DW_AT_name {{.*}}foo
> > > > +; DWWL:       DW_AT_low_pc [DW_FORM_addr] ([[FOOLOW:0x[0-9a-f]+]])
> > > >  ; DWWL:     DW_TAG_compile_unit
> > > >  ; DWWL:       DW_AT_name {{.*}}"bar.c"
> > > > +; DWWL:       DW_AT_low_pc [DW_FORM_addr] ([[BARLOW:0x[0-9a-f]+]])
> > > >  ; DWWL:       DW_TAG_subprogram
> > > >  ; DWWL-NOT:     DW_AT_{{[lowhigh]*}}_pc
> > > >  ; DWWL:         DW_AT_name {{.*}}foo
> > > > @@ -141,3 +139,20 @@ entry:
> > > >  ; DWWL:         DW_AT_name {{.*}}bar
> > > >  ; DWWL:         DW_TAG_inlined_subroutine
> > > >  ; DWWL:           DW_AT_abstract_origin
> > > > +
> > > > +; DW-LABEL:   .debug_line contents:
> > > > +; Check that the low_pc entries from above hit the right files.
> > > > +
> > > > +; DWLW-LABEL: file_names[{{ *}}1]{{.*}} bar.c
> > > > +; DWLW:       [[BARLOW]]  0 0 1 0 0 is_stmt
> > > > +; DWLW:       [[BARLOW]]  2 0 1 0 0 is_stmt prologue_end
> > > > +; DWLW-LABEL: file_names[{{ *}}1]{{.*}} foo.c
> > > > +; DWLW:       [[FOOLOW]]  0 0 1 0 0 is_stmt
> > > > +; DWLW:       [[FOOLOW]] 52 0 1 0 0 is_stmt prologue_end
> > > > +
> > > > +; DWWL-LABEL: file_names[{{ *}}1]{{.*}} foo.c
> > > > +; DWWL:       [[FOOLOW]]  0 0 1 0 0 is_stmt
> > > > +; DWWL:       [[FOOLOW]] 52 0 1 0 0 is_stmt prologue_end
> > > > +; DWWL-LABEL: file_names[{{ *}}1]{{.*}} bar.c
> > > > +; DWWL:       [[BARLOW]]  0 0 1 0 0 is_stmt
> > > > +; DWWL:       [[BARLOW]]  2 0 1 0 0 is_stmt prologue_end
> > > >
> > > >
> > > > _______________________________________________
> > > > llvm-commits mailing list
> > > > llvm-commits at cs.uiuc.edu
> > > > http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
> > > >
>
>
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