[llvm-gsymutil] Don't warn about duplicate debug info for merged functions

Author: alx32

llvm/include/llvm/DebugInfo/GSYM/GsymCreator.h

@@ -147,7 +147,8 @@ class GsymCreator {
   bool IsSegment = false;
   bool Finalized = false;
   bool Quiet;
-
+  // Specifies weather the input might contain merged functions
+  bool InputHasMergedFunctions;
 
   /// Get the first function start address.
   ///
@@ -292,7 +293,12 @@ class GsymCreator {
   }
 
 public:
-  GsymCreator(bool Quiet = false);
+  /// Construct a GsymCreator object.
+  ///
+  /// \param Quiet Whether to suppress warning messages
+  /// \param InputHasMergedFunctions Weather the input might contain merged
+  /// functions - functions with identical address ranges.
+  GsymCreator(bool Quiet = false, bool InputHasMergedFunctions = false);
 
   /// Save a GSYM file to a stand alone file.
   ///

llvm/lib/DebugInfo/GSYM/GsymCreator.cpp

@@ -21,8 +21,9 @@
 using namespace llvm;
 using namespace gsym;
 
-GsymCreator::GsymCreator(bool Quiet)
-    : StrTab(StringTableBuilder::ELF), Quiet(Quiet) {
+GsymCreator::GsymCreator(bool Quiet, bool InputHasMergedFunctions)
+    : StrTab(StringTableBuilder::ELF), Quiet(Quiet),
+      InputHasMergedFunctions(InputHasMergedFunctions) {
   insertFile(StringRef());
 }
 
@@ -315,12 +316,16 @@ llvm::Error GsymCreator::finalize(OutputAggregator &Out) {
               std::swap(Prev, Curr);
             }
           } else {
-            Out.Report("Overlapping function ranges", [&](raw_ostream &OS) {
-              // print warnings about overlaps
-              OS << "warning: function ranges overlap:\n"
-                << Prev << "\n"
-                << Curr << "\n";
-            });
+            // Equal ranges are invalid only in the case where merged functions
+            // are not expected.
+            if (!InputHasMergedFunctions) {
+              Out.Report("Overlapping function ranges", [&](raw_ostream &OS) {
+                // print warnings about overlaps
+                OS << "warning: function ranges overlap:\n"
+                   << Prev << "\n"
+                   << Curr << "\n";
+              });
+            }
             FinalizedFuncs.emplace_back(std::move(Curr));
           }
         } else {

llvm/test/tools/llvm-gsymutil/ARM_AArch64/macho-merged-funcs-dwarf.yaml

@@ -1,16 +1,18 @@
 # RUN: yaml2obj %s -o %t.dSYM
 
 ## Verify that we don't keep merged functions by default
-# RUN: llvm-gsymutil --num-threads=1 --convert %t.dSYM --out-file=%t.default.gSYM
+# RUN: llvm-gsymutil --num-threads=1 --convert %t.dSYM --out-file=%t.default.gSYM | FileCheck --check-prefix=CHECK-GSYM-CREATE-NOMERGE %s
 # RUN: llvm-gsymutil --verify --verbose %t.default.gSYM | FileCheck --check-prefix=CHECK-GSYM-DEFAULT %s
 
 ## Verify that we keep merged functions when specyfing --merged-functions
-# RUN: llvm-gsymutil --num-threads=1 --convert %t.dSYM --out-file=%t.keep.gSYM --merged-functions
+# RUN: llvm-gsymutil --num-threads=1 --convert %t.dSYM --out-file=%t.keep.gSYM --merged-functions | FileCheck --check-prefix=CHECK-GSYM-CREATE-MERGE %s
 # RUN: llvm-gsymutil --verify --verbose %t.keep.gSYM | FileCheck --check-prefix=CHECK-GSYM-KEEP %s
 
 ## Note: For identical functions, the dSYM / gSYM cannot be counted on to be deterministic.
 ## So we can only match the general structure, not exact function names / offsets
 
+# CHECK-GSYM-CREATE-NOMERGE: warning: same address range contains different debug info.
+# CHECK-GSYM-CREATE-MERGE-NOT: warning: same address range contains different debug info.
 
 # CHECK-GSYM-DEFAULT-NOT: Merged FunctionInfos
 # CHECK-GSYM-DEFAULT:      FunctionInfo @ 0x{{[0-9a-fA-F]+}}: [0x{{[0-9a-fA-F]+}} - 0x{{[0-9a-fA-F]+}}) "my_func_03"

llvm/tools/llvm-gsymutil/llvm-gsymutil.cpp

@@ -349,7 +349,7 @@ static llvm::Error handleObjectFile(ObjectFile &Obj, const std::string &OutFile,
   auto ThreadCount =
       NumThreads > 0 ? NumThreads : std::thread::hardware_concurrency();
 
-  GsymCreator Gsym(Quiet);
+  GsymCreator Gsym(Quiet, UseMergedFunctions);
 
   // See if we can figure out the base address for a given object file, and if
   // we can, then set the base address to use to this value. This will ease