updateDWARFObjectAddressRanges: nullify low pc

In case the case the DW_AT_ranges tag already exists for the object the
low pc values won't be updated and will be incorrect in
after-bolt binaries.

Vladislav Khmelevsky,
Advanced Software Technology Lab, Huawei

Differential Revision: https://reviews.llvm.org/D117216

3 files changed, 144 insertions, 6 deletions

diff --git a/bolt/lib/Rewrite/DWARFRewriter.cpp b/bolt/lib/Rewrite/DWARFRewriter.cpp
index c0fda71..531f824 100644
--- a/bolt/lib/Rewrite/DWARFRewriter.cpp
+++ b/bolt/lib/Rewrite/DWARFRewriter.cpp
@@ -689,22 +689,27 @@ void DWARFRewriter::updateDWARFObjectAddressRanges(
     }
   }
 
+  Optional<AttrInfo> LowPCAttrInfo =
+      findAttributeInfo(DIE, dwarf::DW_AT_low_pc);
   if (AbbreviationDecl->findAttributeIndex(dwarf::DW_AT_ranges)) {
     // Case 1: The object was already non-contiguous and had DW_AT_ranges.
     // In this case we simply need to update the value of DW_AT_ranges
     // and introduce DW_AT_GNU_ranges_base if required.
     Optional<AttrInfo> AttrVal = findAttributeInfo(DIE, dwarf::DW_AT_ranges);
-
     std::lock_guard<std::mutex> Lock(DebugInfoPatcherMutex);
     DebugInfoPatcher.addLE32Patch(
         AttrVal->Offset, DebugRangesOffset - DebugInfoPatcher.getRangeBase(),
         AttrVal->Size);
-    if (!RangesBase)
+
+    if (!RangesBase) {
+      if (LowPCAttrInfo &&
+          LowPCAttrInfo->V.getForm() != dwarf::DW_FORM_GNU_addr_index &&
+          LowPCAttrInfo->V.getForm() != dwarf::DW_FORM_addrx)
+        DebugInfoPatcher.addLE64Patch(LowPCAttrInfo->Offset, 0);
       return;
+    }
 
     // Convert DW_AT_low_pc into DW_AT_GNU_ranges_base.
-    Optional<AttrInfo> LowPCAttrInfo =
-        findAttributeInfo(DIE, dwarf::DW_AT_low_pc);
     if (!LowPCAttrInfo) {
       errs() << "BOLT-ERROR: skeleton CU at 0x"
              << Twine::utohexstr(DIE.getOffset())
@@ -725,8 +730,9 @@ void DWARFRewriter::updateDWARFObjectAddressRanges(
 
   // Case 2: The object has both DW_AT_low_pc and DW_AT_high_pc emitted back
   // to back. Replace with new attributes and patch the DIE.
-  if (AbbreviationDecl->findAttributeIndex(dwarf::DW_AT_low_pc) &&
-      AbbreviationDecl->findAttributeIndex(dwarf::DW_AT_high_pc)) {
+  Optional<AttrInfo> HighPCAttrInfo =
+      findAttributeInfo(DIE, dwarf::DW_AT_high_pc);
+  if (LowPCAttrInfo && HighPCAttrInfo) {
     convertToRangesPatchAbbrev(*DIE.getDwarfUnit(), AbbreviationDecl,
                                AbbrevWriter, RangesBase);
     convertToRangesPatchDebugInfo(DIE, DebugRangesOffset, DebugInfoPatcher,
diff --git a/bolt/test/AArch64/Inputs/go_dwarf.yaml b/bolt/test/AArch64/Inputs/go_dwarf.yaml
new file mode 100644
index 0000000..aac12a2
--- /dev/null
+++ b/bolt/test/AArch64/Inputs/go_dwarf.yaml
@@ -0,0 +1,79 @@
+--- !ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_DYN
+  Machine:         EM_AARCH64
+  Entry:           0x684
+ProgramHeaders:
+  - Type:            PT_PHDR
+    Flags:           [ PF_R ]
+    VAddr:           0x200
+    Align:           0x8
+  - Type:            PT_INTERP
+    Flags:           [ PF_R ]
+    FirstSec:        .plt
+    LastSec:         .plt
+    VAddr:           0x238
+  - Type:            PT_LOAD
+    Flags:           [ PF_X, PF_R ]
+    FirstSec:        .plt
+    LastSec:         .text
+    Align:           0x10000
+    VAddr:           0x5e8
+Sections:
+  - Name:            .plt
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
+    Address:         0x5F0
+    AddressAlign:    0x10
+    EntSize:         0x10
+    Content:         F07BBFA99000009011CA47F910423E9120021FD61F2003D51F2003D51F2003D59000009011CE47F910623E9120021FD69000009011D247F910823E9120021FD69000009011D647F910A23E9120021FD69000009011DA47F910C23E9120021FD69000009011DE47F910E23E9120021FD6
+  - Name:            .text
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
+    Address:         0x660
+    AddressAlign:    0x8
+    Content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
+  - Name:            .debug_info
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x1
+    Content:         B100000004000000000008011F0000000C000000000C00000000000000600600000000000000000000029E0000000101059000000060060000000000008406000000000000019C9000000003610001020990000000CA6204050000000200900000006D00000005970000000600077806000000000000A900000008015009033008000000000000080151030B4AF10000090405696E74000A08A40000000B0108A30000000C9D0000000D0500000005000000020000
+  - Name:            .debug_abbrev
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x1
+    Content:         011101250E130B030E1B0E5517110110170000022E013F19030E3A0B3B0B390B49131101120140189742190113000003340003083A0B3B0B390B49131C0D0000042E013F19030E3A0B3B0B271949133C19011300000505004913000006180000000789820101110131130000088A820100021891421800000924000B0B3E0B030800000A0F000B0B491300000B24000B0B3E0B030E00000C2600491300000D2E003F193C196E0E030E3A0B3B0B000000
+  - Name:            .debug_line
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x1
+    Content:         5C0000000300290000000401FB0E0D0001010101000000010000010065782E63010000003C6275696C742D696E3E0000000000050C00090260060000000000000105051313050C0610050522050C2C050522050C1E0505140501210203000101
+Symbols:
+  - Name:            main
+    Type:            STT_FUNC
+    Section:         .text
+    Binding:         STB_GLOBAL
+    Value:           0x660
+    Size:            0x24
+DWARF:
+  debug_str:
+    - te.c
+    - printf
+    - '/home/test/test/te'
+    - 'GNU C17 9.3.0 -mlittle-endian -mabi=lp64 -g -O3 -fasynchronous-unwind-tables -fstack-protector-strong -fstack-clash-protection'
+    - main
+    - char
+  debug_aranges:
+    - Length:          0x2C
+      Version:         2
+      CuOffset:        0x0
+      AddressSize:     0x8
+      Descriptors:
+        - Address:         0x660
+          Length:          0x24
+  debug_ranges:
+    - Offset:          0x0
+      AddrSize:        0x8
+      Entries:
+        - LowOffset:       0x0
+          HighOffset:      0x24
+...
diff --git a/bolt/test/AArch64/go_dwarf.test b/bolt/test/AArch64/go_dwarf.test
new file mode 100644
index 0000000..7788568
--- /dev/null
+++ b/bolt/test/AArch64/go_dwarf.test
@@ -0,0 +1,53 @@
+# Check that the llvm-bolt update the dwarf information correctly in case:
+#  - DW_AT_low_pc is nullified in case the DW_AT_ranges tag already exists.
+#  - DW_AT_high_pc is in the form of DW_FORM_addr.
+
+RUN: yaml2obj %p/Inputs/go_dwarf.yaml &> %t.exe
+RUN: llvm-bolt %t.exe -o %t.bolt -update-debug-sections
+
+# Check the original binary values.
+RUN: llvm-dwarfdump -debug-info %t.exe |& \
+RUN:   FileCheck %s -check-prefix=CHECKORIG
+
+CHECKORIG:         DW_TAG_compile_unit
+CHECKORIG-NEXT:        DW_AT_producer
+CHECKORIG-NEXT:        DW_AT_language
+CHECKORIG-NEXT:        DW_AT_name
+CHECKORIG-NEXT:        DW_AT_comp_dir
+CHECKORIG-NEXT:        DW_AT_ranges      (0x00000000
+CHECKORIG-NEXT:           [0x0000000000000660, 0x0000000000000684))
+CHECKORIG-NEXT:        DW_AT_low_pc      (0x0000000000000660)
+
+CHECKORIG:         DW_TAG_subprogram
+CHECKORIG-NEXT:        DW_AT_external  (true)
+CHECKORIG-NEXT:        DW_AT_name      ("main")
+CHECKORIG-NEXT:        DW_AT_decl_file
+CHECKORIG-NEXT:        DW_AT_decl_line (1)
+CHECKORIG-NEXT:        DW_AT_decl_column       (0x05)
+CHECKORIG-NEXT:        DW_AT_type      (0x00000090 "int")
+CHECKORIG-NEXT:        DW_AT_low_pc    (0x0000000000000660)
+CHECKORIG-NEXT:        DW_AT_high_pc   (0x0000000000000684)
+
+
+# Check the bolted binary.
+RUN: llvm-dwarfdump -debug-info %t.bolt |& FileCheck %s
+
+CHECK:         DW_TAG_compile_unit
+CHECK-NEXT:        DW_AT_producer
+CHECK-NEXT:        DW_AT_language
+CHECK-NEXT:        DW_AT_name
+CHECK-NEXT:        DW_AT_comp_dir
+CHECK-NEXT:        DW_AT_ranges      (0x00000010
+CHECK-NEXT:           [0x0000000000000660, 0x0000000000000684))
+CHECK-NEXT:        DW_AT_low_pc      (0x0000000000000000)
+CHECK-NEXT:        DW_AT_stmt_list   (0x00000000)
+
+CHECK:         DW_TAG_subprogram
+CHECK-NEXT:        DW_AT_external  (true)
+CHECK-NEXT:        DW_AT_name      ("main")
+CHECK-NEXT:        DW_AT_decl_file
+CHECK-NEXT:        DW_AT_decl_line (1)
+CHECK-NEXT:        DW_AT_decl_column       (0x05)
+CHECK-NEXT:        DW_AT_type      (0x00000090 "int")
+CHECK-NEXT:        DW_AT_low_pc    (0x0000000000000660)
+CHECK-NEXT:        DW_AT_high_pc   (0x0000000000000684)