diff --git a/lib/Linker/LinkModules.cpp b/lib/Linker/LinkModules.cpp index d1000dc9a9f..e884f452f03 100644 --- a/lib/Linker/LinkModules.cpp +++ b/lib/Linker/LinkModules.cpp @@ -1250,9 +1250,10 @@ void ModuleLinker::linkNamedMDNodes() { /// Drop DISubprograms that have been superseded.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::stripReplacedSubprograms() { 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::stripReplacedSubprograms() { DITypedArray SPs(CU.getSubprograms()); assert(SPs && "Expected valid subprogram array"); - SmallVector 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))); } } diff --git a/test/Linker/Inputs/subprogram-linkonce-weak.ll b/test/Linker/Inputs/subprogram-linkonce-weak.ll new file mode 100644 index 00000000000..1bc440abc3d --- /dev/null +++ b/test/Linker/Inputs/subprogram-linkonce-weak.ll @@ -0,0 +1,16 @@ +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) +} + +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: 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) +!4 = !MDSubroutineType(types: !{}) diff --git a/test/Linker/replaced-function-matches-first-subprogram.ll b/test/Linker/replaced-function-matches-first-subprogram.ll index 508e28da565..ac6633d1c01 100644 --- a/test/Linker/replaced-function-matches-first-subprogram.ll +++ b/test/Linker/replaced-function-matches-first-subprogram.ll @@ -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. diff --git a/test/Linker/subprogram-linkonce-weak.ll b/test/Linker/subprogram-linkonce-weak.ll new file mode 100644 index 00000000000..e6bb79628e2 --- /dev/null +++ b/test/Linker/subprogram-linkonce-weak.ll @@ -0,0 +1,140 @@ +; 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: ){{$}} +; LW: ![[WCU]] = !MDCompileUnit({{.*}} subprograms: ![[WSPs:[0-9]+]] +; LW: ![[WSPs]] = !{![[WEAKFOOSP:[0-9]+]]} +; LW: ![[WEAKFOOSP]] = !MDSubprogram(name: "foo", +; LW-SAME: function: i32 (i32, i32)* @foo +; LW: ![[FOOINBAR]] = !MDLocation(line: 2, scope: ![[FOOSP]], inlinedAt: ![[BARIA:[0-9]+]]) +; LW: ![[BARIA]] = !MDLocation(line: 12, scope: ![[BARSP]]) +; LW: ![[BARRET]] = !MDLocation(line: 13, scope: ![[BARSP]]) +; LW: ![[FOOCALL]] = !MDLocation(line: 2, scope: ![[WEAKFOOSP]]) +; LW: ![[FOORET]] = !MDLocation(line: 3, scope: ![[WEAKFOOSP]]) + +; Same as above, but reordered. +; WL: ![[WCU]] = !MDCompileUnit({{.*}} subprograms: ![[WSPs:[0-9]+]] +; WL: ![[WSPs]] = !{![[WEAKFOOSP:[0-9]+]]} +; WL: ![[WEAKFOOSP]] = !MDSubprogram(name: "foo", +; WL-SAME: function: i32 (i32, i32)* @foo +; WL: ![[LCU]] = !MDCompileUnit({{.*}} subprograms: ![[LSPs:[0-9]+]] +; WL: ![[LSPs]] = !{![[BARSP:[0-9]+]], ![[FOOSP:[0-9]+]]} +; WL: ![[BARSP]] = !MDSubprogram(name: "bar", +; WL-SAME: function: i32 (i32, i32)* @bar +; WL: ![[FOOSP]] = {{.*}}!MDSubprogram(name: "foo", +; Note, for symmetry, this should be "NOT: function:" and "SAME: ){{$}}". +; WL-SAME: function: i32 (i32, i32)* @foo +; WL: ![[FOOCALL]] = !MDLocation(line: 2, scope: ![[WEAKFOOSP]]) +; WL: ![[FOORET]] = !MDLocation(line: 3, 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: 2) +!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=info | FileCheck %s -check-prefix=DWLW +; RUN: %llc_dwarf -filetype=obj -O0 %t2 -o %t2.o +; RUN: llvm-dwarfdump %t2.o -debug-dump=info | FileCheck %s -check-prefix=DWWL + +; DWLW: DW_TAG_compile_unit +; DWLW: DW_AT_name {{.*}}"bar.c" +; DWLW: DW_TAG_subprogram +; DWLW-NOT: DW_AT_{{[lowhigh]*}}_pc +; DWLW: DW_AT_name {{.*}}foo +; DWLW-NOT: DW_AT_{{[lowhigh]*}}_pc +; DWLW: DW_TAG_subprogram +; DWLW: DW_AT_low_pc +; DWLW: DW_AT_high_pc +; DWLW: DW_AT_name {{.*}}bar +; 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 + +; 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_TAG_compile_unit +; DWWL: DW_AT_name {{.*}}"bar.c" +; DWWL: DW_TAG_subprogram +; DWWL-NOT: DW_AT_{{[lowhigh]*}}_pc +; DWWL: DW_AT_name {{.*}}foo +; DWWL-NOT: DW_AT_{{[lowhigh]*}}_pc +; DWWL: DW_TAG_subprogram +; DWWL: DW_AT_low_pc +; DWWL: DW_AT_high_pc +; DWWL: DW_AT_name {{.*}}bar +; DWWL: DW_TAG_inlined_subroutine +; DWWL: DW_AT_abstract_origin