Support inline class member functions in stack trace.

Summary:
Actually class inline functions exist in both .debug_info and .debug_types sections. In this diff, only the information in .debug_info is used.

Step 1. Find the DW_TAG_inlined_subroutine debug info entry (DIE) based on the given address.
Step 2. Find the DW_TAG_subprogram DIE based on the DW_AT_abstract_origin attr in inlined_subroutine, but this DIE is just a declaration.
Step 3. Find the actual definition DW_TAG_subprogram DIE based on the DW_AT_specification attr.

```
.debug_info

0x00003657:           DW_TAG_subprogram [56] *   ---- step 3
                        DW_AT_linkage_name [DW_FORM_strp] ( .debug_str[0x0002932d] = "_ZN5folly10symbolizer4test24ClassWithInlineFunctions9inlineBarERNS0_10FrameArrayILm100EEE")
                        DW_AT_name [DW_FORM_strp] ( .debug_str[0x00014064] = "inlineBar")
                        DW_AT_decl_file [DW_FORM_data1] (0x18)
                        DW_AT_decl_line [DW_FORM_data1] (0xa1)
                        DW_AT_declaration [DW_FORM_flag_present]  (true)
                        DW_AT_external [DW_FORM_flag_present] (true)
                        DW_AT_accessibility [DW_FORM_data1] (0x01)

…

0x0000cd74:   DW_TAG_subprogram [203] * .   ---- step 2
                DW_AT_specification [DW_FORM_ref4]  (cu + 0x358f => {0x00003657})
                DW_AT_inline [DW_FORM_data1]  (0x01)
                DW_AT_object_pointer [DW_FORM_ref4] (cu + 0xccb7 => {0x0000cd7f})

…
0x0000cda0:   DW_TAG_subprogram [181] *
                DW_AT_low_pc [DW_FORM_addr] (0x00000000002a4980)
                DW_AT_high_pc [DW_FORM_data4] (0x00001e22)
                DW_AT_frame_base [DW_FORM_exprloc]  (<0x1> 56 )
                DW_AT_object_pointer [DW_FORM_ref4] (cu + 0xccf0 => {0x0000cdb8})
                DW_AT_specification [DW_FORM_ref4]  (cu + 0x312f => {0x000031f7})

…

0x0000ce02:     DW_TAG_inlined_subroutine [157] *               ---- step 1
                  DW_AT_abstract_origin [DW_FORM_ref4]  (cu + 0xccac => {0x0000cd74})
                  DW_AT_low_pc [DW_FORM_addr] (0x00000000002a4f66)
                  DW_AT_high_pc [DW_FORM_data4] (0x000000c0)
                  DW_AT_call_file [DW_FORM_data1] (0x18)
                  DW_AT_call_line [DW_FORM_data1] (0xe6)

.debug_types

0x00020fdf:         DW_TAG_class_type [33] *
                      DW_AT_calling_convention [DW_FORM_data1]  (0x05)
                      DW_AT_name [DW_FORM_strp] ( .debug_str[0x00067094] = "ClassWithInlineFunctions")
                      DW_AT_byte_size [DW_FORM_data1] (0x08)
                      DW_AT_decl_file [DW_FORM_data1] (0x18)
                      DW_AT_decl_line [DW_FORM_data1] (0x9f)

…

0x00020ff5:           DW_TAG_subprogram [56] *
                        DW_AT_linkage_name [DW_FORM_strp] ( .debug_str[0x0002932d] = "_ZN5folly10symbolizer4test24ClassWithInlineFunctions9inlineBarERNS0_10FrameArrayILm100EEE")
                        DW_AT_name [DW_FORM_strp] ( .debug_str[0x00014064] = "inlineBar")
                        DW_AT_decl_file [DW_FORM_data1] (0x18)
                        DW_AT_decl_line [DW_FORM_data1] (0xa1)
                        DW_AT_declaration [DW_FORM_flag_present]  (true)
                        DW_AT_external [DW_FORM_flag_present] (true)
                        DW_AT_accessibility [DW_FORM_data1] (0x01)

```

Reviewed By: luciang

Differential Revision: D19384064

fbshipit-source-id: a2a6397b94aab9de58d013cf4ad19e658e180d31

folly/experimental/symbolizer/Dwarf.cpp

@@ -637,9 +637,31 @@ detail::Die Dwarf::getDieAtOffset(
   die.abbr = !cu.abbrCache.empty() && die.code < kMaxAbbreviationEntries
       ? cu.abbrCache[die.code - 1]
       : getAbbreviation(die.code, cu.abbrevOffset);
+
   return die;
 }
 
+detail::Die Dwarf::findDefinitionDie(
+    const detail::CompilationUnit& cu,
+    const detail::Die& die) const {
+  // Find the real definition instead of declaration.
+  folly::Optional<uint64_t> offset;
+  forEachAttribute(cu, die, [&](const detail::Attribute& attr) {
+    // Incomplete, non-defining, or separate declaration corresponding to
+    // a declaration
+    if (attr.spec.name == DW_AT_specification) {
+      offset = boost::get<uint64_t>(attr.attrValue);
+      return false;
+    }
+    return true;
+  });
+
+  if (!offset.hasValue()) {
+    return die;
+  }
+  return getDieAtOffset(cu, cu.offset + offset.value());
+}
+
 size_t Dwarf::forEachChild(
     const detail::CompilationUnit& cu,
     const detail::Die& die,
@@ -698,7 +720,6 @@ void Dwarf::findSubProgramDieForAddress(
       uint64_t lowPc = 0;
       uint64_t highPc = 0;
       bool isHighPcAddr = false;
-      StringPiece name;
       forEachAttribute(cu, childDie, [&](const detail::Attribute& attr) {
         switch (attr.spec.name) {
           // Here DW_AT_ranges is not supported since it requires looking up
@@ -712,9 +733,6 @@ void Dwarf::findSubProgramDieForAddress(
             isHighPcAddr = (attr.spec.form == DW_FORM_addr);
             highPc = boost::get<uint64_t>(attr.attrValue);
             break;
-          case DW_AT_name:
-            name = boost::get<StringPiece>(attr.attrValue);
-            break;
         }
         // Iterate through all attributes until find all above.
         return true;
@@ -784,12 +802,15 @@ void Dwarf::findInlinedSubroutineDieForAddress(
     if (originRefType == DW_FORM_ref1 || originRefType == DW_FORM_ref2 ||
         originRefType == DW_FORM_ref4 || originRefType == DW_FORM_ref8 ||
         originRefType == DW_FORM_ref_udata) {
-      isrLoc[0].die = getDieAtOffset(cu, cu.offset + origin);
+      // Jump to the actual function definition instead of declaration for name
+      // and line info.
+      isrLoc[0].die =
+          findDefinitionDie(cu, getDieAtOffset(cu, cu.offset + origin));
       isrLoc.advance(1);
       findInlinedSubroutineDieForAddress(cu, childDie, address, isrLoc);
     } else if (originRefType == DW_FORM_ref_addr) {
       auto srcu = findCompilationUnit(debugInfo_, origin);
-      isrLoc[0].die = getDieAtOffset(cu, origin);
+      isrLoc[0].die = findDefinitionDie(cu, getDieAtOffset(cu, origin));
       isrLoc.advance(1);
       findInlinedSubroutineDieForAddress(srcu, childDie, address, isrLoc);
     }

folly/experimental/symbolizer/Dwarf.h

@@ -149,6 +149,13 @@ class Dwarf {
   detail::Die getDieAtOffset(const detail::CompilationUnit& cu, uint64_t offset)
       const;
 
+  /**
+   * Find the actual definition DIE instead of declaration for the given die.
+   */
+  detail::Die findDefinitionDie(
+      const detail::CompilationUnit& cu,
+      const detail::Die& die) const;
+
   /**
    * Iterates over all children of a debugging info entry, calling the given
    * callable for each. Iteration is stopped early if any of the calls return

folly/experimental/symbolizer/test/SymbolizerTest.cpp

@@ -134,7 +134,9 @@ TEST(SymbolizerTest, SymbolCache) {
 namespace {
 
 size_t kQsortCallLineNo = 0;
-size_t kFooCallLineNo = 0;
+size_t kFooCallByStandaloneBarLineNo = 0;
+size_t kFooCallByClassBarLineNo = 0;
+size_t kFooCallByClassStaticBarLineNo = 0;
 
 template <size_t kNumFrames = 100>
 FOLLY_ALWAYS_INLINE void inlineFoo(FrameArray<kNumFrames>& frames) {
@@ -148,12 +150,59 @@ FOLLY_ALWAYS_INLINE void inlineFoo(FrameArray<kNumFrames>& frames) {
 
 template <size_t kNumFrames = 100>
 FOLLY_ALWAYS_INLINE void inlineBar(FrameArray<kNumFrames>& frames) {
-  kFooCallLineNo = __LINE__ + 1;
+  kFooCallByStandaloneBarLineNo = __LINE__ + 1;
   inlineFoo(frames);
 }
 
+void verifyStackTrace(
+    const FrameArray<100>& frames,
+    const std::string& barName,
+    size_t barLine) {
+  EXPECT_TRUE(frames.frameCount == 14 || frames.frameCount == 15);
+  EXPECT_EQ("inlineFoo<100>", std::string(frames.frames[5].name));
+  EXPECT_EQ(
+      "folly/experimental/symbolizer/test/SymbolizerTest.cpp",
+      std::string(frames.frames[5].location.file.toString()));
+  EXPECT_EQ(kQsortCallLineNo, frames.frames[5].location.line);
+  EXPECT_EQ(barName, std::string(frames.frames[6].name));
+  EXPECT_EQ(
+      "folly/experimental/symbolizer/test/SymbolizerTest.cpp",
+      std::string(frames.frames[6].location.file.toString()));
+  EXPECT_EQ(barLine, frames.frames[6].location.line);
+}
+
+template <size_t kNumFrames = 100>
+void compareFrames(
+    const FrameArray<kNumFrames>& frames1,
+    const FrameArray<kNumFrames>& frames2) {
+  EXPECT_EQ(frames1.frameCount, frames2.frameCount);
+  for (size_t i = 0; i < frames1.frameCount; i++) {
+    EXPECT_STREQ(frames1.frames[i].name, frames2.frames[i].name);
+  }
+}
+
 } // namespace
 
+class ClassWithInlineFunctions {
+ public:
+  FOLLY_ALWAYS_INLINE void inlineBar(FrameArray<100>& frames) const {
+    kFooCallByClassBarLineNo = __LINE__ + 1;
+    inlineFoo(frames);
+  }
+
+  FOLLY_ALWAYS_INLINE static void staticInlineBar(FrameArray<100>& frames) {
+    kFooCallByClassStaticBarLineNo = __LINE__ + 1;
+    inlineFoo(frames);
+  }
+
+  // Dummy non-inline function.
+  size_t dummy() const {
+    return dummy_;
+  }
+
+  size_t dummy_ = 0;
+};
+
 TEST(SymbolizerTest, InlineFunctionBasic) {
   Symbolizer symbolizer(nullptr, LocationInfoMode::FULL_WITH_INLINE, 0);
 
@@ -180,25 +229,34 @@ TEST(SymbolizerTest, InlineFunctionBasic) {
   //  Frame: _ZN7testing8UnitTest3RunEv
   //  Frame: _Z13RUN_ALL_TESTSv
   // clang-format on
-  EXPECT_TRUE(frames.frameCount == 14 || frames.frameCount == 15);
-  EXPECT_EQ("inlineFoo<100>", std::string(frames.frames[5].name));
-  EXPECT_EQ(
-      "folly/experimental/symbolizer/test/SymbolizerTest.cpp",
-      std::string(frames.frames[5].location.file.toString()));
-  EXPECT_EQ(kQsortCallLineNo, frames.frames[5].location.line);
-  EXPECT_EQ("inlineBar<100>", std::string(frames.frames[6].name));
-  EXPECT_EQ(
-      "folly/experimental/symbolizer/test/SymbolizerTest.cpp",
-      std::string(frames.frames[6].location.file.toString()));
-  EXPECT_EQ(kFooCallLineNo, frames.frames[6].location.line);
+  verifyStackTrace(frames, "inlineBar<100>", kFooCallByStandaloneBarLineNo);
 
   FrameArray<100> frames2;
   inlineBar<100>(frames2);
   symbolizer.symbolize(frames2);
-  EXPECT_EQ(frames.frameCount, frames2.frameCount);
-  for (size_t i = 0; i < frames.frameCount; i++) {
-    EXPECT_STREQ(frames.frames[i].name, frames2.frames[i].name);
-  }
+
+  compareFrames(frames, frames2);
+}
+
+TEST(SymbolizerTest, InlineClassMemberFunction) {
+  Symbolizer symbolizer(nullptr, LocationInfoMode::FULL_WITH_INLINE, 0);
+
+  FrameArray<100> frames;
+  ClassWithInlineFunctions obj;
+  obj.inlineBar(frames);
+  symbolizer.symbolize(frames);
+
+  verifyStackTrace(frames, "inlineBar", kFooCallByClassBarLineNo);
+}
+
+TEST(SymbolizerTest, StaticInlineClassMemberFunction) {
+  Symbolizer symbolizer(nullptr, LocationInfoMode::FULL_WITH_INLINE, 0);
+
+  FrameArray<100> frames;
+  ClassWithInlineFunctions::staticInlineBar(frames);
+  symbolizer.symbolize(frames);
+
+  verifyStackTrace(frames, "staticInlineBar", kFooCallByClassStaticBarLineNo);
 }
 
 // No inline frames should be filled because of no extra frames.
@@ -213,9 +271,7 @@ TEST(SymbolizerTest, InlineFunctionBasicNoExtraFrames) {
   inlineBar<8>(frames2);
   symbolizer2.symbolize(frames2);
 
-  for (size_t i = 0; i < frames.frameCount; i++) {
-    EXPECT_STREQ(frames.frames[i].name, frames2.frames[i].name);
-  }
+  compareFrames<8>(frames, frames2);
 }
 
 TEST(SymbolizerTest, InlineFunctionWithCache) {
@@ -225,25 +281,12 @@ TEST(SymbolizerTest, InlineFunctionWithCache) {
   inlineBar<100>(frames);
   symbolizer.symbolize(frames);
 
-  EXPECT_TRUE(frames.frameCount == 14 || frames.frameCount == 15);
-  EXPECT_EQ("inlineFoo<100>", std::string(frames.frames[5].name));
-  EXPECT_EQ(
-      "folly/experimental/symbolizer/test/SymbolizerTest.cpp",
-      std::string(frames.frames[5].location.file.toString()));
-  EXPECT_EQ(kQsortCallLineNo, frames.frames[5].location.line);
-  EXPECT_EQ("inlineBar<100>", std::string(frames.frames[6].name));
-  EXPECT_EQ(
-      "folly/experimental/symbolizer/test/SymbolizerTest.cpp",
-      std::string(frames.frames[6].location.file.toString()));
-  EXPECT_EQ(kFooCallLineNo, frames.frames[6].location.line);
+  verifyStackTrace(frames, "inlineBar<100>", kFooCallByStandaloneBarLineNo);
 
   FrameArray<100> frames2;
   inlineBar<100>(frames2);
   symbolizer.symbolize(frames2);
-  EXPECT_EQ(frames.frameCount, frames2.frameCount);
-  for (size_t i = 0; i < frames.frameCount; i++) {
-    EXPECT_STREQ(frames.frames[i].name, frames2.frames[i].name);
-  }
+  compareFrames(frames, frames2);
 }
 
 } // namespace test