Do a better job at emitting prefrabricated skeleton CUs.

This is a better fix than r308708 for the problem introduced in
r304020. It restores the skeleton CU testcases modified by that commit
to their original form and most importantly ensures that
frontend-generated skeleton CUs (such as used to point to Clang
modules) come after the regular CUs. This broke for DICompileUnit
nodes that don't have any immediate children because they are now
constructed lazily instead of the order in which they are listed in
!llvm.dbg.cu. After this commit we still don't guarantee that order,
but we do guarantee that empty skeletons come last.

Shipping versions of LLDB are very sensitive to the ordering of
CUs. I'll track a fix for LLDB to be more permissive separately.
This fixes a test failure in the LLDB testsuite.

rdar://problem/33357252

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@309154 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 9533d61d08ae46c92c0994c2de5f6d004fc539ba..70fe1e233ba2fb0df39d6c91d2b7df2001e9bf3c 100644 (file)
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -520,6 +520,14 @@ sortGlobalExprs(SmallVectorImpl<DwarfCompileUnit::GlobalExpr> &GVEs) {
   return GVEs;
 }
 
+static bool isEmptyCU(DICompileUnit *CUNode) {
+  return CUNode->getEnumTypes().empty() &&
+         CUNode->getRetainedTypes().empty() &&
+         CUNode->getGlobalVariables().empty() &&
+         CUNode->getImportedEntities().empty() &&
+         CUNode->getMacros().empty();
+}
+
 // Emit all Dwarf sections that should come prior to the content. Create
 // global DIEs and emit initial debug info sections. This is invoked by
 // the target AsmPrinter.
@@ -546,10 +554,7 @@ void DwarfDebug::beginModule() {
   }
 
   for (DICompileUnit *CUNode : M->debug_compile_units()) {
-    if (CUNode->getEnumTypes().empty() && CUNode->getRetainedTypes().empty() &&
-        CUNode->getGlobalVariables().empty() &&
-        CUNode->getImportedEntities().empty() && CUNode->getMacros().empty() &&
-        !CUNode->getDWOId())
+    if (isEmptyCU(CUNode))
       continue;
 
     DwarfCompileUnit &CU = getOrCreateDwarfCompileUnit(CUNode);
@@ -683,6 +688,11 @@ void DwarfDebug::finalizeModuleInfo() {
                         TLOF.getDwarfMacinfoSection()->getBeginSymbol());
   }
 
+  // Emit all frontend-produced Skeleton CUs, i.e., Clang modules.
+  for (auto *CUNode : MMI->getModule()->debug_compile_units())
+    if (CUNode->getDWOId() && isEmptyCU(CUNode))
+      getOrCreateDwarfCompileUnit(CUNode);
+
   // Compute DIE offsets and sizes.
   InfoHolder.computeSizeAndOffsets();
   if (useSplitDwarf())

diff --git a/test/DebugInfo/Generic/skeletoncu.ll b/test/DebugInfo/Generic/skeletoncu.ll
index b9761b2ab565b1a6914a5093ffbb54afa4af415f..1bdfe1fdfe52fa34c401c46840099285a8aec146 100644 (file)
--- a/test/DebugInfo/Generic/skeletoncu.ll
+++ b/test/DebugInfo/Generic/skeletoncu.ll
@@ -14,4 +14,3 @@
 !4 = !{i32 2, !"Debug Info Version", i32 3}
 !5 = !{!6}
 !6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
-

diff --git a/test/DebugInfo/dwo.ll b/test/DebugInfo/dwo.ll
index b6de943c0239e77f7445cd153d99bc3dc5c8b190..7b02c3c88b7f89ca1199e57b32b9e41564ba2dc0 100644 (file)
--- a/test/DebugInfo/dwo.ll
+++ b/test/DebugInfo/dwo.ll
@@ -1,17 +1,23 @@
 ; RUN: %llc_dwarf %s -filetype=obj -o %t
 ; RUN: llvm-dwarfdump -debug-dump=info %t | FileCheck %s
+; REQUIRES: default_triple
+;
+; CHECK: DW_TAG_compile_unit
+; CHECK-NOT: dwo_id
+;
+; The skeleton must come second or LLDB may get confused.
 ; CHECK: DW_TAG_compile_unit
 ; CHECK: DW_AT_GNU_dwo_id {{.*}}abcd
-; CHECK-NOT: DW_AT_GNU_dwo_name
-; REQUIRES: default_triple
+; CHECK: DW_AT_GNU_dwo_name {{.*}}"my.dwo"
 
-!llvm.dbg.cu = !{!0}
+!llvm.dbg.cu = !{!7, !0}
 !llvm.module.flags = !{!3, !4}
 
-!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "LLVM", isOptimized: false, runtimeVersion: 2, emissionKind: FullDebug, enums: !2, retainedTypes: !5, globals: !2, imports: !2, dwoId: 43981)
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "Clang", isOptimized: false, runtimeVersion: 2, splitDebugFilename: "my.dwo", emissionKind: FullDebug, enums: !2, retainedTypes: !2, globals: !2, imports: !2, dwoId: 43981)
 !1 = !DIFile(filename: "<stdin>", directory: "/")
 !2 = !{}
 !3 = !{i32 2, !"Dwarf Version", i32 4}
 !4 = !{i32 2, !"Debug Info Version", i32 3}
 !5 = !{!6}
 !6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!7 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "Clang", isOptimized: false, runtimeVersion: 2, emissionKind: FullDebug, retainedTypes: !5)

diff --git a/test/DebugInfo/skeletoncu.ll b/test/DebugInfo/skeletoncu.ll
index 4c96d82036e7953b972c900b8b3400d21b6b49ac..a90c8b355ce24170f95e42ab08c1de000666776a 100644 (file)
--- a/test/DebugInfo/skeletoncu.ll
+++ b/test/DebugInfo/skeletoncu.ll
@@ -8,11 +8,9 @@
 !llvm.dbg.cu = !{!0}
 !llvm.module.flags = !{!3, !4}
 
-!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "LLVM", isOptimized: false, runtimeVersion: 2, splitDebugFilename: "my.dwo", emissionKind: FullDebug, enums: !2, retainedTypes: !6, globals: !2, imports: !2, dwoId: 43981)
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "LLVM", isOptimized: false, runtimeVersion: 2, splitDebugFilename: "my.dwo", emissionKind: FullDebug, enums: !2, retainedTypes: !2, globals: !2, imports: !2, dwoId: 43981)
 !1 = !DIFile(filename: "<stdin>", directory: "/")
 !2 = !{}
 !3 = !{i32 2, !"Dwarf Version", i32 4}
 !4 = !{i32 2, !"Debug Info Version", i32 3}
-!5 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
-!6 = !{!5}