From 066f09ec5988007b65291528e292a26ef7582a8f Mon Sep 17 00:00:00 2001
From: Francis Ricci <francisjricci@gmail.com>
Date: Fri, 6 Oct 2017 17:43:37 +0000
Subject: [PATCH] [dsymutil] Emit valid debug locations when no symbol flags
 are set

Summary:
swiftc emits symbols without flags set, which led dsymutil to ignore
them when searching for global symbols, causing dwarf location data
to be omitted. Xcode's dsymutil handles this case correctly, and emits
valid location data. Add this functionality to llvm-dsymutil by
allowing parsing of symbols with no flags set.

Reviewers: aprantl, friss, JDevlieghere

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D38587

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315082 91177308-0d34-0410-b5e6-96231b3b80d8
---
 test/tools/dsymutil/Inputs/swift-dwarf-loc.ll | 25 +++++++++++++++++++
 test/tools/dsymutil/X86/swift-dwarf-loc.test  |  9 +++++++
 tools/dsymutil/MachODebugMapParser.cpp        |  4 ++-
 3 files changed, 37 insertions(+), 1 deletion(-)
 create mode 100644 test/tools/dsymutil/Inputs/swift-dwarf-loc.ll
 create mode 100644 test/tools/dsymutil/X86/swift-dwarf-loc.test

diff --git a/test/tools/dsymutil/Inputs/swift-dwarf-loc.ll b/test/tools/dsymutil/Inputs/swift-dwarf-loc.ll
new file mode 100644
index 00000000000..c2e70508c9d
--- /dev/null
+++ b/test/tools/dsymutil/Inputs/swift-dwarf-loc.ll
@@ -0,0 +1,25 @@
+; ModuleID = '-'
+source_filename = "-"
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.12"
+
+%TSi = type <{ i64 }>
+
+@_var = hidden global %TSi zeroinitializer, align 8, !dbg !0
+
+!llvm.dbg.cu = !{!8}
+!llvm.module.flags = !{!11, !12}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = distinct !DIGlobalVariable(name: "x", linkageName: "_var", scope: !2, file: !3, line: 1, type: !4, isLocal: false, isDefinition: true)
+!2 = !DIModule(scope: null, name: "main")
+!3 = !DIFile(filename: "<stdin>", directory: "")
+!4 = !DICompositeType(tag: DW_TAG_structure_type, name: "Int", scope: !6, file: !5, size: 64, elements: !7, runtimeLang: DW_LANG_Swift, identifier: "_T0SiD")
+!5 = !DIFile(filename: "foo", directory: "/tmp")
+!6 = !DIModule(scope: null, name: "foo", includePath: "")
+!7 = !{}
+!8 = distinct !DICompileUnit(language: DW_LANG_Swift, file: !9, producer: "swiftc", isOptimized: false, flags: "", runtimeVersion: 4, emissionKind: FullDebug, enums: !7, globals: !10, imports: null)
+!9 = !DIFile(filename: "/tmp", directory: "")
+!10 = !{!0}
+!11 = !{i32 2, !"Dwarf Version", i32 4}
+!12 = !{i32 2, !"Debug Info Version", i32 3}
diff --git a/test/tools/dsymutil/X86/swift-dwarf-loc.test b/test/tools/dsymutil/X86/swift-dwarf-loc.test
new file mode 100644
index 00000000000..c8e8afc7411
--- /dev/null
+++ b/test/tools/dsymutil/X86/swift-dwarf-loc.test
@@ -0,0 +1,9 @@
+RUN: llc -filetype=obj %p/../Inputs/swift-dwarf-loc.ll -mtriple x86_64-apple-darwin -o %T/swift-dwarf-loc.o
+RUN: ld -dylib %T/swift-dwarf-loc.o -arch x86_64 -lSystem -macosx_version_min 10.9.0 -o %T/swift-dwarf-loc
+RUN: llvm-dsymutil %T/swift-dwarf-loc -no-output -verbose | FileCheck %s
+
+This test checks that dsymutil generates a valid dwarf location for a symbol with no flags set.
+
+CHECK: __var,
+CHECK-NOT: __var,{{.*}}binAddr: 0x0000000000000000
+CHECK-NOT: __var{{.*}} => 0000000000000000
diff --git a/tools/dsymutil/MachODebugMapParser.cpp b/tools/dsymutil/MachODebugMapParser.cpp
index 79b19137119..0cd6a89cc01 100644
--- a/tools/dsymutil/MachODebugMapParser.cpp
+++ b/tools/dsymutil/MachODebugMapParser.cpp
@@ -482,7 +482,9 @@ void MachODebugMapParser::loadMainBinarySymbols(
     // are the only ones that need to be queried because the address
     // of common data won't be described in the debug map. All other
     // addresses should be fetched for the debug map.
-    if (!(Sym.getFlags() & SymbolRef::SF_Global))
+    uint8_t SymType =
+        MainBinary.getSymbolTableEntry(Sym.getRawDataRefImpl()).n_type;
+    if (!(SymType & (MachO::N_EXT | MachO::N_PEXT)))
       continue;
     Expected<section_iterator> SectionOrErr = Sym.getSection();
     if (!SectionOrErr) {
-- 
2.50.1