5 files changed, 249 insertions, 7 deletions
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index 4e90c10e3e9..e40541e57d5 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -964,8 +964,8 @@ DIE &DwarfCompileUnit::constructCallSiteEntryDIE(
     addAddress(CallSiteDIE, getDwarf5OrGNUAttr(dwarf::DW_AT_call_target),
                MachineLocation(CallReg));
   } else {
-    DIE *CalleeDIE = getOrCreateSubprogramDIE(CalleeSP);
-    assert(CalleeDIE && "Could not create DIE for call site entry origin");
+    DIE *CalleeDIE = getDIE(CalleeSP);
+    assert(CalleeDIE && "Could not find DIE for call site entry origin");
     addDIEEntry(CallSiteDIE, getDwarf5OrGNUAttr(dwarf::DW_AT_call_origin),
                 *CalleeDIE);
   }
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 708cef896b5..4def44cd776 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -535,6 +535,14 @@ void DwarfDebug::constructAbstractSubprogramScopeDIE(DwarfCompileUnit &SrcCU,
   }
 }
 
+DIE &DwarfDebug::constructSubprogramDefinitionDIE(const DISubprogram *SP) {
+  DICompileUnit *Unit = SP->getUnit();
+  assert(SP->isDefinition() && "Subprogram not a definition");
+  assert(Unit && "Subprogram definition without parent unit");
+  auto &CU = getOrCreateDwarfCompileUnit(Unit);
+  return *CU.getOrCreateSubprogramDIE(SP);
+}
+
 /// Try to interpret values loaded into registers that forward parameters
 /// for \p CallMI. Store parameters with interpreted value into \p Params.
 static void collectCallSiteParameters(const MachineInstr *CallMI,
@@ -745,6 +753,15 @@ void DwarfDebug::constructCallSiteEntryDIEs(const DISubprogram &SP,
         if (!CalleeDecl || !CalleeDecl->getSubprogram())
           continue;
         CalleeSP = CalleeDecl->getSubprogram();
+
+        if (CalleeSP->isDefinition()) {
+          // Ensure that a subprogram DIE for the callee is available in the
+          // appropriate CU.
+          constructSubprogramDefinitionDIE(CalleeSP);
+        } else {
+          assert(CU.getDIE(CalleeSP) &&
+                 "Expected declaration subprogram DIE for callee");
+        }
       }
 
       // TODO: Omit call site entries for runtime calls (objc_msgSend, etc).
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 6f54c528a50..2e547f12412 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -437,6 +437,9 @@ class DwarfDebug : public DebugHandlerBase {
   /// Construct a DIE for this abstract scope.
   void constructAbstractSubprogramScopeDIE(DwarfCompileUnit &SrcCU, LexicalScope *Scope);
 
+  /// Construct a DIE for the subprogram definition \p SP and return it.
+  DIE &constructSubprogramDefinitionDIE(const DISubprogram *SP);
+
   /// Construct DIEs for call site entries describing the calls in \p MF.
   void constructCallSiteEntryDIEs(const DISubprogram &SP, DwarfCompileUnit &CU,
                                   DIE &ScopeDIE, const MachineFunction &MF);
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index 86522a85427..58d7a4eaa7e 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -188,8 +188,9 @@ int64_t DwarfUnit::getDefaultLowerBound() const {
 
 /// Check whether the DIE for this MDNode can be shared across CUs.
 bool DwarfUnit::isShareableAcrossCUs(const DINode *D) const {
-  // When the MDNode can be part of the type system, the DIE can be shared
-  // across CUs.
+  // When the MDNode can be part of the type system (this includes subprogram
+  // declarations *and* subprogram definitions, even local definitions), the
+  // DIE must be shared across CUs.
   // Combining type units and cross-CU DIE sharing is lower value (since
   // cross-CU DIE sharing is used in LTO and removes type redundancy at that
   // level already) but may be implementable for some value in projects
@@ -197,9 +198,7 @@ bool DwarfUnit::isShareableAcrossCUs(const DINode *D) const {
   // together.
   if (isDwoUnit() && !DD->shareAcrossDWOCUs())
     return false;
-  return (isa<DIType>(D) ||
-          (isa<DISubprogram>(D) && !cast<DISubprogram>(D)->isDefinition())) &&
-         !DD->generateTypeUnits();
+  return (isa<DIType>(D) || isa<DISubprogram>(D)) && !DD->generateTypeUnits();
 }
 
 DIE *DwarfUnit::getDIE(const DINode *D) const {
diff --git a/llvm/test/DebugInfo/X86/lto-cross-cu-call-origin-ref.ll b/llvm/test/DebugInfo/X86/lto-cross-cu-call-origin-ref.ll
new file mode 100644
index 00000000000..db14b06fc51
--- /dev/null
+++ b/llvm/test/DebugInfo/X86/lto-cross-cu-call-origin-ref.ll
@@ -0,0 +1,223 @@
+; RUN: llc -mtriple=x86_64-apple-darwin -filetype=obj < %s -o %t.o
+; RUN: llvm-dwarfdump %t.o | FileCheck %s -implicit-check-not=DW_TAG_subprogram
+; RUN: llvm-dwarfdump --verify %t.o
+
+; This test checks that cross-CU references within call site tags to subprogram
+; definitions are well-formed. There are 5 cases checked in this test. Each set
+; of checks is numbered and has a brief summary.
+
+; Instructions to regenerate the IR:
+; clang -O1 -g -emit-llvm -o a.bc -c a.c
+; clang -O1 -g -emit-llvm -o b.bc -c b.c
+; llvm-link -o linked.bc a.bc b.bc
+; opt -O1 linked.bc -o merged.bc
+
+; Source:
+; // a.c
+; __attribute__((optnone)) void noinline_func_in_a() {}
+;
+; __attribute__((optnone)) static void foo() {}
+; __attribute__((always_inline)) void always_inline_helper_in_a_that_calls_foo() {
+;   foo();
+; }
+;
+; extern void func_from_b();
+; void call_func_in_b_from_a() {
+;   func_from_b();
+; }
+;
+; // b.c
+; extern void noinline_func_in_a();
+; void call_noinline_func_in_a_from_b() {
+;   noinline_func_in_a();
+; }
+;
+; __attribute__((optnone)) void foo() {}
+; extern void always_inline_helper_in_a_that_calls_foo();
+; void call_both_foos_from_b() {
+;   foo();
+;   always_inline_helper_in_a_that_calls_foo();
+; }
+;
+; __attribute__((optnone)) void func_from_b() {}
+; void call_func_in_b_from_b() {
+;   func_from_b();
+; }
+
+; === CU for a.c ===
+
+; CHECK: DW_TAG_compile_unit
+; CHECK:   DW_AT_name ("a.c")
+
+; CHECK: DW_TAG_subprogram
+; CHECK:   DW_AT_name ("func_from_b")
+; CHECK:   DW_AT_declaration (true)
+
+; CHECK: 0x{{0+}}[[NOINLINE_FUNC_IN_A:.*]]: DW_TAG_subprogram
+; CHECK:   DW_AT_name ("noinline_func_in_a")
+
+; 1) Check that "always_inline_helper_in_a_that_calls_foo" calls the "foo" in
+; a.c, and *not* the "foo" in b.c.
+; CHECK: 0x{{0+}}[[ALWAYS_INLINE_HELPER_IN_A:.*]]: DW_TAG_subprogram
+; CHECK:   DW_AT_abstract_origin ({{.*}} "always_inline_helper_in_a_that_calls_foo")
+; CHECK:   DW_TAG_call_site
+; CHECK-NEXT: DW_AT_call_origin (0x{{0+}}[[FOO_IN_A:.*]])
+
+; CHECK: 0x{{0+}}[[FOO_IN_A]]: DW_TAG_subprogram
+; CHECK:   DW_AT_name ("foo")
+
+; 2) Check that "call_func_in_b_from_a" has a cross-CU ref into b.c.
+; CHECK: DW_TAG_subprogram
+; CHECK:   DW_AT_name ("call_func_in_b_from_a")
+; CHECK:   DW_TAG_call_site
+; CHECK-NEXT: DW_AT_call_origin (0x{{0+}}[[FUNC_FROM_B:.*]])
+
+; CHECK: DW_TAG_subprogram
+; CHECK:   DW_AT_name ("always_inline_helper_in_a_that_calls_foo")
+; CHECK:   DW_AT_inline (DW_INL_inlined)
+
+; === CU for b.c ===
+
+; CHECK: DW_TAG_compile_unit
+; CHECK:   DW_AT_name ("b.c")
+
+; CHECK: DW_TAG_subprogram
+; CHECK:   DW_AT_name ("noinline_func_in_a")
+; CHECK:   DW_AT_declaration (true)
+
+; CHECK: DW_TAG_subprogram
+; CHECK:   DW_AT_name ("always_inline_helper_in_a_that_calls_foo")
+; CHECK:   DW_AT_declaration (true)
+
+; 3) Validate the cross-CU ref from "call_func_in_b_from_a" in a.c.
+; CHECK: 0x{{0+}}[[FUNC_FROM_B]]: DW_TAG_subprogram
+; CHECK:   DW_AT_name ("func_from_b")
+
+; 4) Validate the cross-CU ref from "call_noinline_func_in_a_from_b" in b.c.
+; CHECK: DW_TAG_subprogram
+; CHECK:   DW_AT_name ("call_noinline_func_in_a_from_b")
+; CHECK:   DW_TAG_call_site
+; CHECK-NEXT: DW_AT_call_origin (0x{{0+}}[[NOINLINE_FUNC_IN_A]])
+
+; CHECK: 0x{{0+}}[[FOO_IN_B:.*]]: DW_TAG_subprogram
+; CHECK:   DW_AT_name ("foo")
+
+; 5) Validate that we correctly emit a cross-CU ref when the call is inlined
+; from another CU.
+; CHECK: DW_TAG_subprogram
+; CHECK:   DW_AT_name ("call_both_foos_from_b")
+; CHECK:   DW_TAG_call_site
+; CHECK-NEXT: DW_AT_call_origin (0x{{0+}}[[FOO_IN_B]])
+; CHECK:   DW_TAG_call_site
+; CHECK-NEXT: DW_AT_call_origin (0x{{0+}}[[FOO_IN_A]])
+
+; CHECK: DW_TAG_subprogram
+; CHECK:   DW_AT_name ("call_func_in_b_from_b")
+; CHECK:   DW_TAG_call_site
+; CHECK-NEXT: DW_AT_call_origin (0x{{0+}}[[FUNC_FROM_B]])
+
+target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.14.0"
+
+define void @noinline_func_in_a() local_unnamed_addr #0 !dbg !17 {
+entry:
+  ret void, !dbg !20
+}
+
+define void @always_inline_helper_in_a_that_calls_foo() local_unnamed_addr #1 !dbg !21 {
+entry:
+  tail call fastcc void @foo.2(), !dbg !22
+  ret void, !dbg !23
+}
+
+define internal fastcc void @foo.2() unnamed_addr #0 !dbg !24 {
+entry:
+  ret void, !dbg !25
+}
+
+define void @call_func_in_b_from_a() local_unnamed_addr !dbg !26 {
+entry:
+  tail call void @func_from_b() #3, !dbg !27
+  ret void, !dbg !28
+}
+
+define void @call_noinline_func_in_a_from_b() local_unnamed_addr !dbg !29 {
+entry:
+  tail call void @noinline_func_in_a() #3, !dbg !30
+  ret void, !dbg !31
+}
+
+define void @foo() local_unnamed_addr #0 !dbg !32 {
+entry:
+  ret void, !dbg !33
+}
+
+define void @call_both_foos_from_b() local_unnamed_addr !dbg !34 {
+entry:
+  tail call void @foo(), !dbg !35
+  tail call fastcc void @foo.2() #3, !dbg !36
+  ret void, !dbg !38
+}
+
+define void @func_from_b() local_unnamed_addr #0 !dbg !39 {
+entry:
+  ret void, !dbg !40
+}
+
+define void @call_func_in_b_from_b() local_unnamed_addr !dbg !41 {
+entry:
+  tail call void @func_from_b(), !dbg !42
+  ret void, !dbg !43
+}
+
+attributes #0 = { noinline }
+attributes #1 = { alwaysinline }
+
+!llvm.dbg.cu = !{!0, !7}
+!llvm.ident = !{!12, !12}
+!llvm.module.flags = !{!13, !14, !15, !16}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 10.0.0 (git@github.com:llvm/llvm-project.git 310e85309f870ee7347ef979d7d8da9bf28e92ea)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3, nameTableKind: None)
+!1 = !DIFile(filename: "a.c", directory: "/Users/vsk/tmp/lto-entry-vals")
+!2 = !{}
+!3 = !{!4}
+!4 = !DISubprogram(name: "func_from_b", scope: !1, file: !1, line: 8, type: !5, spFlags: DISPFlagOptimized, retainedNodes: !2)
+!5 = !DISubroutineType(types: !6)
+!6 = !{null, null}
+!7 = distinct !DICompileUnit(language: DW_LANG_C99, file: !8, producer: "clang version 10.0.0 (git@github.com:llvm/llvm-project.git 310e85309f870ee7347ef979d7d8da9bf28e92ea)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !9, nameTableKind: None)
+!8 = !DIFile(filename: "b.c", directory: "/Users/vsk/tmp/lto-entry-vals")
+!9 = !{!10, !11}
+!10 = !DISubprogram(name: "noinline_func_in_a", scope: !8, file: !8, line: 1, type: !5, spFlags: DISPFlagOptimized, retainedNodes: !2)
+!11 = !DISubprogram(name: "always_inline_helper_in_a_that_calls_foo", scope: !8, file: !8, line: 7, type: !5, spFlags: DISPFlagOptimized, retainedNodes: !2)
+!12 = !{!"clang version 10.0.0 (git@github.com:llvm/llvm-project.git 310e85309f870ee7347ef979d7d8da9bf28e92ea)"}
+!13 = !{i32 7, !"Dwarf Version", i32 4}
+!14 = !{i32 2, !"Debug Info Version", i32 3}
+!15 = !{i32 1, !"wchar_size", i32 4}
+!16 = !{i32 7, !"PIC Level", i32 2}
+!17 = distinct !DISubprogram(name: "noinline_func_in_a", scope: !1, file: !1, line: 1, type: !18, scopeLine: 1, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2)
+!18 = !DISubroutineType(types: !19)
+!19 = !{null}
+!20 = !DILocation(line: 1, column: 53, scope: !17)
+!21 = distinct !DISubprogram(name: "always_inline_helper_in_a_that_calls_foo", scope: !1, file: !1, line: 4, type: !18, scopeLine: 4, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2)
+!22 = !DILocation(line: 5, column: 3, scope: !21)
+!23 = !DILocation(line: 6, column: 1, scope: !21)
+!24 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 3, type: !18, scopeLine: 3, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagLocalToUnit | DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2)
+!25 = !DILocation(line: 3, column: 45, scope: !24)
+!26 = distinct !DISubprogram(name: "call_func_in_b_from_a", scope: !1, file: !1, line: 9, type: !18, scopeLine: 9, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2)
+!27 = !DILocation(line: 10, column: 3, scope: !26)
+!28 = !DILocation(line: 11, column: 1, scope: !26)
+!29 = distinct !DISubprogram(name: "call_noinline_func_in_a_from_b", scope: !8, file: !8, line: 2, type: !18, scopeLine: 2, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !7, retainedNodes: !2)
+!30 = !DILocation(line: 3, column: 3, scope: !29)
+!31 = !DILocation(line: 4, column: 1, scope: !29)
+!32 = distinct !DISubprogram(name: "foo", scope: !8, file: !8, line: 6, type: !18, scopeLine: 6, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !7, retainedNodes: !2)
+!33 = !DILocation(line: 6, column: 38, scope: !32)
+!34 = distinct !DISubprogram(name: "call_both_foos_from_b", scope: !8, file: !8, line: 8, type: !18, scopeLine: 8, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !7, retainedNodes: !2)
+!35 = !DILocation(line: 9, column: 3, scope: !34)
+!36 = !DILocation(line: 5, column: 3, scope: !21, inlinedAt: !37)
+!37 = distinct !DILocation(line: 10, column: 3, scope: !34)
+!38 = !DILocation(line: 11, column: 1, scope: !34)
+!39 = distinct !DISubprogram(name: "func_from_b", scope: !8, file: !8, line: 13, type: !18, scopeLine: 13, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !7, retainedNodes: !2)
+!40 = !DILocation(line: 13, column: 46, scope: !39)
+!41 = distinct !DISubprogram(name: "call_func_in_b_from_b", scope: !8, file: !8, line: 14, type: !18, scopeLine: 14, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !7, retainedNodes: !2)
+!42 = !DILocation(line: 15, column: 3, scope: !41)
+!43 = !DILocation(line: 16, column: 1, scope: !41)