Improve behavior of DebugInfoEntryMinimal::getSubprogramName() introduced in r159512.

To fetch a subprogram name we should not only inspect the DIE for this subprogram, but optionally inspect
its specification, or its abstract origin (even if there is no inlining), or even specification of an abstract origin.

Reviewed by Benjamin Kramer.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160365 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 35 insertions, 28 deletions

diff --git a/lib/DebugInfo/DWARFContext.cpp b/lib/DebugInfo/DWARFContext.cpp
index 6be230e73a..08e5db2206 100644
--- a/lib/DebugInfo/DWARFContext.cpp
+++ b/lib/DebugInfo/DWARFContext.cpp
@@ -155,8 +155,10 @@ DILineInfo DWARFContext::getLineInfoForAddress(uint64_t address,
   if (specifier.needs(DILineInfoSpecifier::FunctionName)) {
     const DWARFDebugInfoEntryMinimal *function_die =
         cu->getFunctionDIEForAddress(address);
-    if (function_die)
-      functionName = function_die->getSubprogramName(cu);
+    if (function_die) {
+      if (const char *name = function_die->getSubprogramName(cu))
+        functionName = name;
+    }
   }
   if (specifier.needs(DILineInfoSpecifier::FileLineInfo)) {
     // Get the line table for this compile unit.
diff --git a/lib/DebugInfo/DWARFDebugInfoEntry.cpp b/lib/DebugInfo/DWARFDebugInfoEntry.cpp
index 1024b45255..429a36c087 100644
--- a/lib/DebugInfo/DWARFDebugInfoEntry.cpp
+++ b/lib/DebugInfo/DWARFDebugInfoEntry.cpp
@@ -456,35 +456,38 @@ DWARFDebugInfoEntryMinimal::addressRangeContainsAddress(
   return false;
 }
 
-static inline const char*
-getSubprogramNameFromDie(const DWARFCompileUnit *cu,
-                         const DWARFDebugInfoEntryMinimal *die) {
-  const char *result = 0;
-  if (!die->isNULL() && die->getTag() == DW_TAG_subprogram) {
-    // Try to get mangled name if possible.
-    result = die->getAttributeValueAsString(cu, DW_AT_MIPS_linkage_name, 0);
-    if (result == 0)
-      result = die->getAttributeValueAsString(cu, DW_AT_linkage_name, 0);
-    if (result == 0)
-      result = die->getAttributeValueAsString(cu, DW_AT_name, 0);
-  }
-  return result;
-}
-
 const char*
 DWARFDebugInfoEntryMinimal::getSubprogramName(
     const DWARFCompileUnit *cu) const {
   if (isNULL() || getTag() != DW_TAG_subprogram)
     return 0;
-  const char *name = getSubprogramNameFromDie(cu, this);
-  if (name == 0) {
-    // Try to get name from specification DIE.
-    uint32_t ref = getAttributeValueAsReference(cu, DW_AT_specification, -1U);
-    if (ref != -1U) {
-      DWARFDebugInfoEntryMinimal spec_die;
-      if (spec_die.extract(cu, &ref))
-        name = getSubprogramNameFromDie(cu, &spec_die);
+  // Try to get mangled name if possible.
+  if (const char *name =
+      getAttributeValueAsString(cu, DW_AT_MIPS_linkage_name, 0))
+    return name;
+  if (const char *name = getAttributeValueAsString(cu, DW_AT_linkage_name, 0))
+    return name;
+  if (const char *name = getAttributeValueAsString(cu, DW_AT_name, 0))
+    return name;
+  // Try to get name from specification DIE.
+  uint32_t spec_ref =
+      getAttributeValueAsReference(cu, DW_AT_specification, -1U);
+  if (spec_ref != -1U) {
+    DWARFDebugInfoEntryMinimal spec_die;
+    if (spec_die.extract(cu, &spec_ref)) {
+      if (const char *name = spec_die.getSubprogramName(cu))
+        return name;
     }
   }
-  return name;
+  // Try to get name from abstract origin DIE.
+  uint32_t abs_origin_ref =
+      getAttributeValueAsReference(cu, DW_AT_abstract_origin, -1U);
+  if (abs_origin_ref != -1U) {
+    DWARFDebugInfoEntryMinimal abs_origin_die;
+    if (abs_origin_die.extract(cu, &abs_origin_ref)) {
+      if (const char *name = abs_origin_die.getSubprogramName(cu))
+        return name;
+    }
+  }
+  return 0;
 }
diff --git a/lib/DebugInfo/DWARFDebugInfoEntry.h b/lib/DebugInfo/DWARFDebugInfoEntry.h
index 1a040a53a3..d5d86b9ec0 100644
--- a/lib/DebugInfo/DWARFDebugInfoEntry.h
+++ b/lib/DebugInfo/DWARFDebugInfoEntry.h
@@ -132,8 +132,10 @@ public:
   bool addressRangeContainsAddress(const DWARFCompileUnit *cu,
                                    const uint64_t address) const;
 
-  // If a DIE represents a subroutine, returns its mangled name
-  // (or short name, if mangled is missing). Otherwise returns null.
+  // If a DIE represents a subprogram, returns its mangled name
+  // (or short name, if mangled is missing). This name may be fetched
+  // from specification or abstract origin for this subprogram.
+  // Returns null if no name is found.
   const char* getSubprogramName(const DWARFCompileUnit *cu) const;
 };