[PATCH] D100328: Fixed bug in eh_frame PC offset calculation for DW_EH_PE_pcrel

[Alex Orlov via Phabricator via llvm-commits]

aorlov created this revision.
aorlov added reviewers: dblaikie, RKSimon, kazu.
aorlov added a project: LLVM.
Herald added subscribers: cmtice, rupprecht, hiraditya.
Herald added a reviewer: jhenderson.
Herald added a reviewer: MaskRay.
aorlov requested review of this revision.
Herald added a subscriber: llvm-commits.

To calculate a correct PC offset we need to apply the target address from the eh_frame.

This fixes the following bugs:
https://bugs.llvm.org/show_bug.cgi?id=27249
https://bugs.llvm.org/show_bug.cgi?id=46414


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D100328

Files:
  llvm/include/llvm/DebugInfo/DWARF/DWARFSection.h
  llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
  llvm/test/tools/llvm-dwarfdump/X86/debug_frame_offset.test
  llvm/test/tools/llvm-objdump/MachO/eh_frame-arm64.test


Index: llvm/test/tools/llvm-objdump/MachO/eh_frame-arm64.test
===================================================================
--- llvm/test/tools/llvm-objdump/MachO/eh_frame-arm64.test
+++ llvm/test/tools/llvm-objdump/MachO/eh_frame-arm64.test
@@ -12,7 +12,7 @@
 
 # CHECK:   DW_CFA_def_cfa: reg31 +0
 
-# CHECK: 00000014 00000020 00000018 FDE cie=00000000 pc=00000000...00000020
+# CHECK: 00000014 00000020 00000018 FDE cie=00000000 pc=00000050...00000070
 # CHECK:   DW_CFA_advance_loc: 8
 # CHECK:   DW_CFA_def_cfa_offset: +16
 # CHECK:   DW_CFA_offset: reg30 -8
Index: llvm/test/tools/llvm-dwarfdump/X86/debug_frame_offset.test
===================================================================
--- llvm/test/tools/llvm-dwarfdump/X86/debug_frame_offset.test
+++ llvm/test/tools/llvm-dwarfdump/X86/debug_frame_offset.test
@@ -9,7 +9,7 @@
 RUN: llvm-dwarfdump %p/../../dsymutil/Inputs/basic1.macho.x86_64.o \
 RUN:   -eh-frame=0x00000018 | FileCheck %s --check-prefix=EH
 EH: .eh_frame contents:
-EH-NEXT: 00000018 00000024 0000001c FDE cie=00000000 pc=fffffffffffffd20...fffffffffffffd44
+EH-NEXT: 00000018 00000024 0000001c FDE cie=00000000 pc=00000000...00000024
 EH-NEXT:   Format:       DWARF32
 EH-NEXT:   DW_CFA_advance_loc: 1
 EH-NOT: pc
Index: llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
===================================================================
--- llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
+++ llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
@@ -823,6 +823,8 @@
   if (DebugFrame)
     return DebugFrame.get();
 
+  const DWARFSection &DS = DObj->getFrameSection();
+
   // There's a "bug" in the DWARFv3 standard with respect to the target address
   // size within debug frame sections. While DWARF is supposed to be independent
   // of its container, FDEs have fields with size being "target address size",
@@ -832,9 +834,10 @@
   // provides this information). This problem is fixed in DWARFv4
   // See this dwarf-discuss discussion for more details:
   // http://lists.dwarfstd.org/htdig.cgi/dwarf-discuss-dwarfstd.org/2011-December/001173.html
-  DWARFDataExtractor debugFrameData(*DObj, DObj->getFrameSection(),
-                                    isLittleEndian(), DObj->getAddressSize());
-  auto DF = std::make_unique<DWARFDebugFrame>(getArch(), /*IsEH=*/false);
+  DWARFDataExtractor debugFrameData(*DObj, DS, isLittleEndian(),
+                                    DObj->getAddressSize());
+  auto DF =
+      std::make_unique<DWARFDebugFrame>(getArch(), /*IsEH=*/false, DS.Address);
   if (Error E = DF->parse(debugFrameData))
     return std::move(E);
 
@@ -846,10 +849,12 @@
   if (EHFrame)
     return EHFrame.get();
 
-  DWARFDataExtractor debugFrameData(*DObj, DObj->getEHFrameSection(),
-                                    isLittleEndian(), DObj->getAddressSize());
+  const DWARFSection &DS = DObj->getEHFrameSection();
+  DWARFDataExtractor debugFrameData(*DObj, DS, isLittleEndian(),
+                                    DObj->getAddressSize());
 
-  auto DF = std::make_unique<DWARFDebugFrame>(getArch(), /*IsEH=*/true);
+  auto DF =
+      std::make_unique<DWARFDebugFrame>(getArch(), /*IsEH=*/true, DS.Address);
   if (Error E = DF->parse(debugFrameData))
     return std::move(E);
   DebugFrame.swap(DF);
@@ -1707,6 +1712,9 @@
         if (Name == "debug_ranges") {
           // FIXME: Use the other dwo range section when we emit it.
           RangesDWOSection.Data = Data;
+        } else if (Name == "debug_frame" || Name == "eh_frame") {
+          if (DWARFSection *S = mapNameToDWARFSection(Name))
+            S->Address = Section.getAddress();
         }
       } else if (InfoSectionMap *Sections =
                      StringSwitch<InfoSectionMap *>(Name)
Index: llvm/include/llvm/DebugInfo/DWARF/DWARFSection.h
===================================================================
--- llvm/include/llvm/DebugInfo/DWARF/DWARFSection.h
+++ llvm/include/llvm/DebugInfo/DWARF/DWARFSection.h
@@ -15,6 +15,7 @@
 
 struct DWARFSection {
   StringRef Data;
+  uint64_t Address = {};
 };
 
 struct SectionName {


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