[llvm] r233302 - Reapply "Linker: Drop function pointers for overridden subprograms"
Duncan P. N. Exon Smith
dexonsmith at apple.com
Fri Mar 27 09:48:16 PDT 2015
Nevermind, it looks like Yaron fixed this for me in r233375.
> On 2015-Mar-27, at 09:46, Duncan P. N. Exon Smith <dexonsmith at apple.com> wrote:
>
> @Reid: it looks like these tests fail on your windows self-hots:
>
> http://lab.llvm.org:8011/builders/clang-x86-win2008-selfhost/builds/133
>
> Can you send me the output of the failing llvm-dwarfdumps so I can fix it?
>
>> On 2015-Mar-26, at 11:35, Duncan P. N. Exon Smith <dexonsmith at apple.com> wrote:
>>
>> Author: dexonsmith
>> Date: Thu Mar 26 13:35:30 2015
>> New Revision: 233302
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=233302&view=rev
>> Log:
>> Reapply "Linker: Drop function pointers for overridden subprograms"
>>
>> This reverts commit r233254, effectively reapplying r233164 (and its
>> successors), with an additional testcase for when subprograms match
>> exactly. This fixes PR22792 (again).
>>
>> I'm using the same approach, but I've moved up the call to
>> `stripReplacedSubprograms()`. The function pointers need to be dropped
>> before mapping any metadata from the source module, or else this can
>> drop the function from new subprograms that have merged (via Metadata
>> uniquing) with the old ones. Dropping the pointers first prevents them
>> from merging.
>>
>> **** The original commit message follows. ****
>>
>> Linker: Drop function pointers for overridden subprograms
>>
>> Instead of dropping subprograms that have been overridden, just set
>> their function pointers to `nullptr`. This is a minor adjustment to the
>> stop-gap fix for PR21910 committed in r224487, and fixes the crasher
>> from PR22792.
>>
>> The problem that r224487 put a band-aid on: how do we find the canonical
>> subprogram for a `Function`? Since the backend currently relies on
>> `DebugInfoFinder` (which does a naive in-order traversal of compile
>> units and picks the first subprogram) for this, r224487 tried dropping
>> non-canonical subprograms.
>>
>> Dropping subprograms fails because the backend *also* builds up a map
>> from subprogram to compile unit (`DwarfDebug::SPMap`) based on the
>> subprogram lists. A missing subprogram causes segfaults later when an
>> inlined reference (such as in this testcase) is created.
>>
>> Instead, just drop the `Function` pointer to `nullptr`, which nicely
>> mirrors what happens when an already-inlined `Function` is optimized
>> out. We can't really be sure that it's the same definition anyway, as
>> the testcase demonstrates.
>>
>> This still isn't completely satisfactory. Two flaws at least that I can
>> think of:
>>
>> - I still haven't found a straightforward way to make this symmetric
>> in the IR. (Interestingly, the DWARF output is already symmetric,
>> and I've tested for that to be sure we don't regress.)
>> - Using `DebugInfoFinder` to find the canonical subprogram for a
>> function is kind of crazy. We should just attach metadata to the
>> function, like this:
>>
>> define weak i32 @foo(i32, i32) !dbg !MDSubprogram(...) {
>>
>> Added:
>> llvm/trunk/test/Linker/Inputs/subprogram-linkonce-weak-odr.ll
>> llvm/trunk/test/Linker/Inputs/subprogram-linkonce-weak.ll
>> llvm/trunk/test/Linker/subprogram-linkonce-weak-odr.ll
>> llvm/trunk/test/Linker/subprogram-linkonce-weak.ll
>> Modified:
>> llvm/trunk/lib/Linker/LinkModules.cpp
>> llvm/trunk/test/Linker/replaced-function-matches-first-subprogram.ll
>>
>> Modified: llvm/trunk/lib/Linker/LinkModules.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Linker/LinkModules.cpp?rev=233302&r1=233301&r2=233302&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/Linker/LinkModules.cpp (original)
>> +++ llvm/trunk/lib/Linker/LinkModules.cpp Thu Mar 26 13:35:30 2015
>> @@ -1250,9 +1250,10 @@ void ModuleLinker::linkNamedMDNodes() {
>>
>> /// Drop DISubprograms that have been superseded.
>> ///
>> -/// FIXME: this creates an asymmetric result: we strip losing subprograms from
>> -/// DstM, but leave losing subprograms in SrcM. Instead we should also strip
>> -/// losers from SrcM, but this requires extra plumbing in MapMetadata.
>> +/// FIXME: this creates an asymmetric result: we strip functions from losing
>> +/// subprograms in DstM, but leave losing subprograms in SrcM.
>> +/// TODO: Remove this logic once the backend can correctly determine canonical
>> +/// subprograms.
>> void ModuleLinker::stripReplacedSubprograms() {
>> // Avoid quadratic runtime by returning early when there's nothing to do.
>> if (OverridingFunctions.empty())
>> @@ -1262,8 +1263,8 @@ void ModuleLinker::stripReplacedSubprogr
>> auto Functions = std::move(OverridingFunctions);
>> OverridingFunctions.clear();
>>
>> - // Drop subprograms whose functions have been overridden by the new compile
>> - // unit.
>> + // Drop functions from subprograms if they've been overridden by the new
>> + // compile unit.
>> NamedMDNode *CompileUnits = DstM->getNamedMetadata("llvm.dbg.cu");
>> if (!CompileUnits)
>> return;
>> @@ -1274,19 +1275,15 @@ void ModuleLinker::stripReplacedSubprogr
>> DITypedArray<DISubprogram> SPs(CU.getSubprograms());
>> assert(SPs && "Expected valid subprogram array");
>>
>> - SmallVector<Metadata *, 16> NewSPs;
>> - NewSPs.reserve(SPs.getNumElements());
>> for (unsigned S = 0, SE = SPs.getNumElements(); S != SE; ++S) {
>> DISubprogram SP = SPs.getElement(S);
>> - if (SP && SP.getFunction() && Functions.count(SP.getFunction()))
>> + if (!SP || !SP.getFunction() || !Functions.count(SP.getFunction()))
>> continue;
>>
>> - NewSPs.push_back(SP);
>> + // Prevent DebugInfoFinder from tagging this as the canonical subprogram,
>> + // since the canonical one is in the incoming module.
>> + SP->replaceFunction(nullptr);
>> }
>> -
>> - // Redirect operand to the overriding subprogram.
>> - if (NewSPs.size() != SPs.getNumElements())
>> - CU.replaceSubprograms(DIArray(MDNode::get(DstM->getContext(), NewSPs)));
>> }
>> }
>>
>> @@ -1563,6 +1560,13 @@ bool ModuleLinker::run() {
>> MapValue(GV, ValueMap, RF_None, &TypeMap, &ValMaterializer);
>> }
>>
>> + // Strip replaced subprograms before mapping any metadata -- so that we're
>> + // not changing metadata from the source module (note that
>> + // linkGlobalValueBody() eventually calls RemapInstruction() and therefore
>> + // MapMetadata()) -- but after linking global value protocols -- so that
>> + // OverridingFunctions has been built.
>> + stripReplacedSubprograms();
>> +
>> // Link in the function bodies that are defined in the source module into
>> // DstM.
>> for (Function &SF : *SrcM) {
>> @@ -1585,9 +1589,6 @@ bool ModuleLinker::run() {
>> linkGlobalValueBody(Src);
>> }
>>
>> - // Strip replaced subprograms before linking together compile units.
>> - stripReplacedSubprograms();
>> -
>> // Remap all of the named MDNodes in Src into the DstM module. We do this
>> // after linking GlobalValues so that MDNodes that reference GlobalValues
>> // are properly remapped.
>>
>> Added: llvm/trunk/test/Linker/Inputs/subprogram-linkonce-weak-odr.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Linker/Inputs/subprogram-linkonce-weak-odr.ll?rev=233302&view=auto
>> ==============================================================================
>> --- llvm/trunk/test/Linker/Inputs/subprogram-linkonce-weak-odr.ll (added)
>> +++ llvm/trunk/test/Linker/Inputs/subprogram-linkonce-weak-odr.ll Thu Mar 26 13:35:30 2015
>> @@ -0,0 +1,15 @@
>> +define weak_odr i32 @foo(i32 %a, i32 %b) {
>> +entry:
>> + %sum = add i32 %a, %b, !dbg !MDLocation(line: 2, scope: !3)
>> + ret i32 %sum, !dbg !MDLocation(line: 3, scope: !3)
>> +}
>> +
>> +!llvm.module.flags = !{!0}
>> +!0 = !{i32 2, !"Debug Info Version", i32 3}
>> +
>> +!llvm.dbg.cu = !{!1}
>> +!1 = !MDCompileUnit(language: DW_LANG_C99, file: !2, subprograms: !{!3}, emissionKind: 1)
>> +!2 = !MDFile(filename: "foo.c", directory: "/path/to/dir")
>> +!3 = !MDSubprogram(file: !4, scope: !4, line: 1, name: "foo", function: i32 (i32, i32)* @foo, type: !5)
>> +!4 = !MDFile(filename: "foo.h", directory: "/path/to/dir")
>> +!5 = !MDSubroutineType(types: !{})
>>
>> Added: 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=233302&view=auto
>> ==============================================================================
>> --- llvm/trunk/test/Linker/Inputs/subprogram-linkonce-weak.ll (added)
>> +++ llvm/trunk/test/Linker/Inputs/subprogram-linkonce-weak.ll Thu Mar 26 13:35:30 2015
>> @@ -0,0 +1,16 @@
>> +define weak i32 @foo(i32 %a, i32 %b) {
>> +entry:
>> + %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)
>> +
>> +!llvm.module.flags = !{!0}
>> +!0 = !{i32 2, !"Debug Info Version", i32 3}
>> +
>> +!llvm.dbg.cu = !{!1}
>> +!1 = !MDCompileUnit(language: DW_LANG_C99, file: !2, subprograms: !{!3}, emissionKind: 1)
>> +!2 = !MDFile(filename: "foo.c", directory: "/path/to/dir")
>> +!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/replaced-function-matches-first-subprogram.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Linker/replaced-function-matches-first-subprogram.ll?rev=233302&r1=233301&r2=233302&view=diff
>> ==============================================================================
>> --- llvm/trunk/test/Linker/replaced-function-matches-first-subprogram.ll (original)
>> +++ llvm/trunk/test/Linker/replaced-function-matches-first-subprogram.ll Thu Mar 26 13:35:30 2015
>> @@ -45,9 +45,9 @@ entry:
>> !1 = !MDFile(filename: "t1.cpp", directory: "/Users/dexonsmith/data/llvm/staging/test/Linker/repro/d1")
>> !2 = !{}
>>
>> -; Extract out each compile unit's single subprogram. The replaced subprogram
>> -; should be dropped by the first compile unit.
>> -; CHECK-DAG: ![[SPs1]] = !{![[SP1:[0-9]+]]}
>> +; Extract out each compile unit's single subprogram. The replaced subprogram's
>> +; function should drop to null in the first compile unit.
>> +; CHECK-DAG: ![[SPs1]] = !{![[SP1:[0-9]+]], ![[SP2r:[0-9]+]]}
>> ; CHECK-DAG: ![[SPs2]] = !{![[SP2:[0-9]+]]}
>> !3 = !{!4, !7}
>> !4 = !MDSubprogram(name: "foo", line: 2, isLocal: false, isDefinition: true, flags: DIFlagPrototyped, isOptimized: false, scopeLine: 2, file: !1, scope: !5, type: !6, function: i32 ()* @_Z3foov, variables: !2)
>> @@ -58,6 +58,10 @@ entry:
>> ; subprogram is pointing at the correct function.
>> ; CHECK-DAG: ![[SP1]] = !MDSubprogram({{.*}} function: i32 ()* @_Z3foov
>> ; CHECK-DAG: ![[SP2]] = !MDSubprogram({{.*}} file: ![[FILE:[0-9]+]],{{.*}} function: i32 (%struct.Class*)* @_ZN5ClassIiE3fooEv
>> +
>> +; We can't use CHECK-NOT/CHECK-SAME with a CHECK-DAG, so rely on field order to
>> +; prove that there's no function: here.
>> +; CHECK-DAG: ![[SP2r]] = {{.*}}!MDSubprogram({{.*}} isOptimized: false, variables:
>> !7 = !MDSubprogram(name: "foo", line: 2, isLocal: false, isDefinition: true, flags: DIFlagPrototyped, isOptimized: false, scopeLine: 2, file: !8, scope: !9, type: !6, function: i32 (%struct.Class*)* @_ZN5ClassIiE3fooEv, variables: !2)
>>
>> ; The new subprogram should be pointing at the new directory.
>>
>> Added: llvm/trunk/test/Linker/subprogram-linkonce-weak-odr.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Linker/subprogram-linkonce-weak-odr.ll?rev=233302&view=auto
>> ==============================================================================
>> --- llvm/trunk/test/Linker/subprogram-linkonce-weak-odr.ll (added)
>> +++ llvm/trunk/test/Linker/subprogram-linkonce-weak-odr.ll Thu Mar 26 13:35:30 2015
>> @@ -0,0 +1,177 @@
>> +; RUN: llvm-link %s %S/Inputs/subprogram-linkonce-weak-odr.ll -S -o %t1
>> +; RUN: FileCheck %s -check-prefix=LW -check-prefix=CHECK <%t1
>> +; RUN: llvm-link %S/Inputs/subprogram-linkonce-weak-odr.ll %s -S -o %t2
>> +; RUN: FileCheck %s -check-prefix=WL -check-prefix=CHECK <%t2
>> +
>> +; This testcase tests the following flow:
>> +; - File A defines a linkonce_odr version of @foo which has inlined into @bar.
>> +; - File B defines a weak_odr version of @foo (identical definition).
>> +; - Linkage rules state File B version of @foo wins.
>> +; - Debug info for the subprograms of @foo match exactly. Without
>> +; intervention, the same subprogram would show up in both compile units, and
>> +; it would get associated with the compile unit where it was linkonce.
>> +; - @bar has inlined debug info related to the linkonce_odr @foo.
>> +;
>> +; This checks a corner case for the fix for PR22792, where subprograms match
>> +; exactly. It's a companion for subprogram-linkonce-weak.ll.
>> +
>> +; The LW prefix means linkonce (this file) first, then weak (the other file).
>> +; The WL prefix means weak (the other file) first, then linkonce (this file).
>> +
>> +; We'll see @bar before @foo if this file is first.
>> +; LW-LABEL: define i32 @bar(
>> +; LW: %sum = add i32 %a, %b, !dbg ![[FOOINBAR:[0-9]+]]
>> +; LW: ret i32 %sum, !dbg ![[BARRET:[0-9]+]]
>> +; LW-LABEL: define weak_odr i32 @foo(
>> +; LW: %sum = add i32 %a, %b, !dbg ![[FOOADD:[0-9]+]]
>> +; LW: ret i32 %sum, !dbg ![[FOORET:[0-9]+]]
>> +
>> +; We'll see @foo before @bar if this file is second.
>> +; WL-LABEL: define weak_odr i32 @foo(
>> +; WL: %sum = add i32 %a, %b, !dbg ![[FOOADD:[0-9]+]]
>> +; WL: ret i32 %sum, !dbg ![[FOORET:[0-9]+]]
>> +; WL-LABEL: define i32 @bar(
>> +; WL: %sum = add i32 %a, %b, !dbg ![[FOOINBAR:[0-9]+]]
>> +; WL: ret i32 %sum, !dbg ![[BARRET:[0-9]+]]
>> +
>> +define i32 @bar(i32 %a, i32 %b) {
>> +entry:
>> + %sum = add i32 %a, %b, !dbg !MDLocation(line: 2, scope: !4,
>> + inlinedAt: !MDLocation(line: 12, scope: !3))
>> + ret i32 %sum, !dbg !MDLocation(line: 13, scope: !3)
>> +}
>> +
>> +define linkonce_odr i32 @foo(i32 %a, i32 %b) {
>> +entry:
>> + %sum = add i32 %a, %b, !dbg !MDLocation(line: 2, scope: !4)
>> + ret i32 %sum, !dbg !MDLocation(line: 3, scope: !4)
>> +}
>> +
>> +!llvm.module.flags = !{!0}
>> +!0 = !{i32 2, !"Debug Info Version", i32 3}
>> +
>> +; CHECK-LABEL: !llvm.dbg.cu =
>> +; LW-SAME: !{![[LCU:[0-9]+]], ![[WCU:[0-9]+]]}
>> +; WL-SAME: !{![[WCU:[0-9]+]], ![[LCU:[0-9]+]]}
>> +!llvm.dbg.cu = !{!1}
>> +
>> +; LW: ![[LCU]] = !MDCompileUnit({{.*}} subprograms: ![[LSPs:[0-9]+]]
>> +; LW: ![[LSPs]] = !{![[BARSP:[0-9]+]], ![[FOOSP:[0-9]+]]}
>> +; LW: ![[BARSP]] = !MDSubprogram(name: "bar",
>> +; LW-SAME: function: i32 (i32, i32)* @bar
>> +; LW: ![[FOOSP]] = {{.*}}!MDSubprogram(name: "foo",
>> +; LW-NOT: function:
>> +; LW-SAME: ){{$}}
>> +; LW: ![[WCU]] = !MDCompileUnit({{.*}} subprograms: ![[WSPs:[0-9]+]]
>> +; LW: ![[WSPs]] = !{![[WEAKFOOSP:[0-9]+]]}
>> +; LW: ![[WEAKFOOSP]] = !MDSubprogram(name: "foo",
>> +; LW-SAME: function: i32 (i32, i32)* @foo
>> +; 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: ![[FOOADD]] = !MDLocation(line: 2, scope: ![[WEAKFOOSP]])
>> +; LW: ![[FOORET]] = !MDLocation(line: 3, scope: ![[WEAKFOOSP]])
>> +
>> +; Same as above, but reordered.
>> +; WL: ![[WCU]] = !MDCompileUnit({{.*}} subprograms: ![[WSPs:[0-9]+]]
>> +; WL: ![[WSPs]] = !{![[WEAKFOOSP:[0-9]+]]}
>> +; WL: ![[WEAKFOOSP]] = !MDSubprogram(name: "foo",
>> +; WL-SAME: function: i32 (i32, i32)* @foo
>> +; WL: ![[LCU]] = !MDCompileUnit({{.*}} subprograms: ![[LSPs:[0-9]+]]
>> +; Note: for symmetry, LSPs would have a different copy of the subprogram.
>> +; WL: ![[LSPs]] = !{![[BARSP:[0-9]+]], ![[WEAKFOOSP:[0-9]+]]}
>> +; WL: ![[BARSP]] = !MDSubprogram(name: "bar",
>> +; WL-SAME: function: i32 (i32, i32)* @bar
>> +; WL: ![[FOOADD]] = !MDLocation(line: 2, scope: ![[WEAKFOOSP]])
>> +; WL: ![[FOORET]] = !MDLocation(line: 3, scope: ![[WEAKFOOSP]])
>> +; WL: ![[FOOINBAR]] = !MDLocation(line: 2, scope: ![[WEAKFOOSP]], inlinedAt: ![[BARIA:[0-9]+]])
>> +; WL: ![[BARIA]] = !MDLocation(line: 12, scope: ![[BARSP]])
>> +; WL: ![[BARRET]] = !MDLocation(line: 13, scope: ![[BARSP]])
>> +
>> +!1 = !MDCompileUnit(language: DW_LANG_C99, file: !2, subprograms: !{!3, !4}, emissionKind: 1)
>> +!2 = !MDFile(filename: "bar.c", directory: "/path/to/dir")
>> +!3 = !MDSubprogram(file: !2, scope: !2, line: 11, name: "bar", function: i32 (i32, i32)* @bar, type: !6)
>> +!4 = !MDSubprogram(file: !5, scope: !5, line: 1, name: "foo", function: i32 (i32, i32)* @foo, type: !6)
>> +!5 = !MDFile(filename: "foo.h", directory: "/path/to/dir")
>> +!6 = !MDSubroutineType(types: !{})
>> +
>> +; Crasher for llc.
>> +; REQUIRES: object-emission
>> +; RUN: %llc_dwarf -filetype=obj -O0 %t1 -o %t1.o
>> +; 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
>> +; RUN: llvm-dwarfdump %t2.o -debug-dump=all | FileCheck %s -check-prefix=DWWL -check-prefix=DW
>> +; Check that the debug info puts the subprogram (with PCs) in the correct
>> +; compile unit.
>> +
>> +; DW-LABEL: .debug_info contents:
>> +; DWLW: DW_TAG_compile_unit
>> +; DWLW: DW_AT_name {{.*}}"bar.c"
>> +; Note: If we stop emitting foo here, the comment below for DWWL (and the
>> +; check) should be copied up here.
>> +; DWLW: DW_TAG_subprogram
>> +; DWLW-NOT: DW_AT_low_pc
>> +; DWLW-NOT: DW_AT_high_pc
>> +; DWLW: DW_AT_name {{.*}}foo
>> +; DWLW: DW_AT_decl_file {{.*}}"/path/to/dir/foo.h"
>> +; DWLW: DW_AT_decl_line {{.*}}(1)
>> +; DWLW: DW_TAG_subprogram
>> +; DWLW: DW_AT_low_pc
>> +; DWLW: DW_AT_high_pc
>> +; DWLW: DW_AT_name {{.*}}bar
>> +; DWLW: DW_AT_decl_file {{.*}}"/path/to/dir/bar.c"
>> +; DWLW: DW_AT_decl_line {{.*}}(11)
>> +; DWLW: DW_TAG_inlined_subroutine
>> +; 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_decl_file {{.*}}"/path/to/dir/foo.h"
>> +; DWLW: DW_AT_decl_line {{.*}}(1)
>> +
>> +; 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_decl_file {{.*}}"/path/to/dir/foo.h"
>> +; DWWL: DW_AT_decl_line {{.*}}(1)
>> +; DWWL: DW_TAG_compile_unit
>> +; DWWL: DW_AT_name {{.*}}"bar.c"
>> +; Note: for symmetry, foo would also show up in this compile unit
>> +; (alternatively, it wouldn't show up in the DWLW case). If we start emitting
>> +; foo here, this should be updated by checking that we don't emit low_pc and
>> +; high_pc for it.
>> +; DWWL-NOT: DW_AT_name {{.*}}foo
>> +; DWWL: DW_TAG_subprogram
>> +; DWWL-NOT: DW_AT_name {{.*}}foo
>> +; DWWL: DW_AT_low_pc
>> +; DWWL: DW_AT_high_pc
>> +; DWWL-NOT: DW_AT_name {{.*}}foo
>> +; DWWL: DW_AT_name {{.*}}bar
>> +; DWWL: DW_AT_decl_file {{.*}}"/path/to/dir/bar.c"
>> +; DWWL: DW_AT_decl_line {{.*}}(11)
>> +; DWWL: DW_TAG_inlined_subroutine
>> +; DWWL: DW_AT_abstract_origin
>> +
>> +; DW-LABEL: .debug_line contents:
>> +; Check that we have the right things in the line table as well.
>> +
>> +; DWLW-LABEL: file_names[{{ *}}1]{{.*}} bar.c
>> +; DWLW-LABEL: file_names[{{ *}}2]{{.*}} foo.h
>> +; DWLW: 2 0 2 0 0 is_stmt prologue_end
>> +; DWLW-LABEL: file_names[{{ *}}1]{{.*}} foo.h
>> +; DWLW: 2 0 1 0 0 is_stmt prologue_end
>> +; DWLW-NOT: prologue_end
>> +
>> +; DWWL-LABEL: file_names[{{ *}}1]{{.*}} foo.h
>> +; DWWL: 2 0 1 0 0 is_stmt prologue_end
>> +; DWWL-LABEL: file_names[{{ *}}1]{{.*}} bar.c
>> +; DWWL-LABEL: file_names[{{ *}}2]{{.*}} foo.h
>> +; DWWL: 2 0 2 0 0 is_stmt prologue_end
>> +; DWWL-NOT: prologue_end
>>
>> Added: llvm/trunk/test/Linker/subprogram-linkonce-weak.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Linker/subprogram-linkonce-weak.ll?rev=233302&view=auto
>> ==============================================================================
>> --- llvm/trunk/test/Linker/subprogram-linkonce-weak.ll (added)
>> +++ llvm/trunk/test/Linker/subprogram-linkonce-weak.ll Thu Mar 26 13:35:30 2015
>> @@ -0,0 +1,171 @@
>> +; RUN: llvm-link %s %S/Inputs/subprogram-linkonce-weak.ll -S -o %t1
>> +; RUN: FileCheck %s -check-prefix=LW -check-prefix=CHECK <%t1
>> +; RUN: llvm-link %S/Inputs/subprogram-linkonce-weak.ll %s -S -o %t2
>> +; RUN: FileCheck %s -check-prefix=WL -check-prefix=CHECK <%t2
>> +
>> +; This testcase tests the following flow:
>> +; - File A defines a linkonce version of @foo which has inlined into @bar.
>> +; - File B defines a weak version of @foo (different definition).
>> +; - Linkage rules state File B version of @foo wins.
>> +; - @bar still has inlined debug info related to the linkonce @foo.
>> +;
>> +; This should fix PR22792, although the testcase was hand-written. There's a
>> +; RUN line with a crasher for llc at the end with checks for the DWARF output.
>> +
>> +; The LW prefix means linkonce (this file) first, then weak (the other file).
>> +; The WL prefix means weak (the other file) first, then linkonce (this file).
>> +
>> +; We'll see @bar before @foo if this file is first.
>> +; LW-LABEL: define i32 @bar(
>> +; LW: %sum = add i32 %a, %b, !dbg ![[FOOINBAR:[0-9]+]]
>> +; LW: ret i32 %sum, !dbg ![[BARRET:[0-9]+]]
>> +; LW-LABEL: define weak i32 @foo(
>> +; LW: %sum = call i32 @fastadd(i32 %a, i32 %b), !dbg ![[FOOCALL:[0-9]+]]
>> +; LW: ret i32 %sum, !dbg ![[FOORET:[0-9]+]]
>> +
>> +; We'll see @foo before @bar if this file is second.
>> +; WL-LABEL: define weak i32 @foo(
>> +; WL: %sum = call i32 @fastadd(i32 %a, i32 %b), !dbg ![[FOOCALL:[0-9]+]]
>> +; WL: ret i32 %sum, !dbg ![[FOORET:[0-9]+]]
>> +; WL-LABEL: define i32 @bar(
>> +; WL: %sum = add i32 %a, %b, !dbg ![[FOOINBAR:[0-9]+]]
>> +; WL: ret i32 %sum, !dbg ![[BARRET:[0-9]+]]
>> +
>> +define i32 @bar(i32 %a, i32 %b) {
>> +entry:
>> + %sum = add i32 %a, %b, !dbg !MDLocation(line: 2, scope: !4,
>> + inlinedAt: !MDLocation(line: 12, scope: !3))
>> + ret i32 %sum, !dbg !MDLocation(line: 13, scope: !3)
>> +}
>> +
>> +define linkonce i32 @foo(i32 %a, i32 %b) {
>> +entry:
>> + %sum = add i32 %a, %b, !dbg !MDLocation(line: 2, scope: !4)
>> + ret i32 %sum, !dbg !MDLocation(line: 3, scope: !4)
>> +}
>> +
>> +!llvm.module.flags = !{!0}
>> +!0 = !{i32 2, !"Debug Info Version", i32 3}
>> +
>> +; CHECK-LABEL: !llvm.dbg.cu =
>> +; LW-SAME: !{![[LCU:[0-9]+]], ![[WCU:[0-9]+]]}
>> +; WL-SAME: !{![[WCU:[0-9]+]], ![[LCU:[0-9]+]]}
>> +!llvm.dbg.cu = !{!1}
>> +
>> +; LW: ![[LCU]] = !MDCompileUnit({{.*}} subprograms: ![[LSPs:[0-9]+]]
>> +; LW: ![[LSPs]] = !{![[BARSP:[0-9]+]], ![[FOOSP:[0-9]+]]}
>> +; LW: ![[BARSP]] = !MDSubprogram(name: "bar",
>> +; LW-SAME: function: i32 (i32, i32)* @bar
>> +; LW: ![[FOOSP]] = {{.*}}!MDSubprogram(name: "foo",
>> +; LW-NOT: function:
>> +; LW-SAME: ){{$}}
>> +; LW: ![[WCU]] = !MDCompileUnit({{.*}} subprograms: ![[WSPs:[0-9]+]]
>> +; LW: ![[WSPs]] = !{![[WEAKFOOSP:[0-9]+]]}
>> +; LW: ![[WEAKFOOSP]] = !MDSubprogram(name: "foo",
>> +; LW-SAME: function: i32 (i32, i32)* @foo
>> +; 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: 52, scope: ![[WEAKFOOSP]])
>> +; LW: ![[FOORET]] = !MDLocation(line: 53, scope: ![[WEAKFOOSP]])
>> +
>> +; Same as above, but reordered.
>> +; WL: ![[WCU]] = !MDCompileUnit({{.*}} subprograms: ![[WSPs:[0-9]+]]
>> +; WL: ![[WSPs]] = !{![[WEAKFOOSP:[0-9]+]]}
>> +; WL: ![[WEAKFOOSP]] = !MDSubprogram(name: "foo",
>> +; WL-SAME: function: i32 (i32, i32)* @foo
>> +; WL: ![[LCU]] = !MDCompileUnit({{.*}} subprograms: ![[LSPs:[0-9]+]]
>> +; WL: ![[LSPs]] = !{![[BARSP:[0-9]+]], ![[FOOSP:[0-9]+]]}
>> +; WL: ![[BARSP]] = !MDSubprogram(name: "bar",
>> +; WL-SAME: function: i32 (i32, i32)* @bar
>> +; 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: 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]])
>> +
>> +!1 = !MDCompileUnit(language: DW_LANG_C99, file: !2, subprograms: !{!3, !4}, emissionKind: 1)
>> +!2 = !MDFile(filename: "bar.c", directory: "/path/to/dir")
>> +!3 = !MDSubprogram(file: !2, scope: !2, line: 11, name: "bar", function: i32 (i32, i32)* @bar, type: !5)
>> +!4 = !MDSubprogram(file: !2, scope: !2, line: 1, name: "foo", function: i32 (i32, i32)* @foo, type: !5)
>> +!5 = !MDSubroutineType(types: !{})
>> +
>> +; Crasher for llc.
>> +; REQUIRES: object-emission
>> +; RUN: %llc_dwarf -filetype=obj -O0 %t1 -o %t1.o
>> +; 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
>> +; RUN: llvm-dwarfdump %t2.o -debug-dump=all | FileCheck %s -check-prefix=DWWL -check-prefix=DW
>> +; Check that the debug info for the discarded linkonce version of @foo doesn't
>> +; reference any code, and that the other subprograms look correct.
>> +
>> +; DW-LABEL: .debug_info contents:
>> +; DWLW: DW_TAG_compile_unit
>> +; DWLW: DW_AT_name {{.*}}"bar.c"
>> +; DWLW: DW_TAG_subprogram
>> +; DWLW-NOT: DW_AT_low_pc
>> +; DWLW-NOT: DW_AT_high_pc
>> +; DWLW: DW_AT_name {{.*}}foo
>> +; DWLW: DW_AT_decl_file {{.*}}"/path/to/dir/bar.c"
>> +; DWLW: DW_AT_decl_line {{.*}}(1)
>> +; DWLW: DW_TAG_subprogram
>> +; DWLW: DW_AT_low_pc
>> +; DWLW: DW_AT_high_pc
>> +; DWLW: DW_AT_name {{.*}}bar
>> +; DWLW: DW_AT_decl_file {{.*}}"/path/to/dir/bar.c"
>> +; DWLW: DW_AT_decl_line {{.*}}(11)
>> +
>> +; DWLW: DW_TAG_inlined_subroutine
>> +; 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_decl_file {{.*}}"/path/to/dir/foo.c"
>> +; DWLW: DW_AT_decl_line {{.*}}(51)
>> +
>> +; 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_decl_file {{.*}}"/path/to/dir/foo.c"
>> +; DWWL: DW_AT_decl_line {{.*}}(51)
>> +; DWWL: DW_TAG_compile_unit
>> +; DWWL: DW_AT_name {{.*}}"bar.c"
>> +; DWWL: DW_TAG_subprogram
>> +; DWWL-NOT: DW_AT_low_pc
>> +; DWWL-NOT: DW_AT_high_pc
>> +; DWWL: DW_AT_name {{.*}}foo
>> +; DWWL: DW_AT_decl_file {{.*}}"/path/to/dir/bar.c"
>> +; DWWL: DW_AT_decl_line {{.*}}(1)
>> +; DWWL: DW_TAG_subprogram
>> +; DWWL: DW_AT_low_pc
>> +; DWWL: DW_AT_high_pc
>> +; DWWL: DW_AT_name {{.*}}bar
>> +; DWWL: DW_AT_decl_file {{.*}}"/path/to/dir/bar.c"
>> +; DWWL: DW_AT_decl_line {{.*}}(11)
>> +; DWWL: DW_TAG_inlined_subroutine
>> +; DWWL: DW_AT_abstract_origin
>> +
>> +; DW-LABEL: .debug_line contents:
>> +; Check that we have the right things in the line table as well.
>> +
>> +; DWLW-LABEL: file_names[{{ *}}1]{{.*}} bar.c
>> +; DWLW: 2 0 1 0 0 is_stmt prologue_end
>> +; DWLW-LABEL: file_names[{{ *}}1]{{.*}} foo.c
>> +; DWLW: 52 0 1 0 0 is_stmt prologue_end
>> +; DWLW-NOT: prologue_end
>> +
>> +; DWWL-LABEL: file_names[{{ *}}1]{{.*}} foo.c
>> +; DWWL: 52 0 1 0 0 is_stmt prologue_end
>> +; DWWL-LABEL: file_names[{{ *}}1]{{.*}} bar.c
>> +; DWWL: 2 0 1 0 0 is_stmt prologue_end
>> +; DWWL-NOT: prologue_end
>>
>>
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