[DebugInfo] Fix reading location tables headers of v5 units in DWP.

This fixes the reading of location lists headers for compilation units in package files by adjusting the reading offset according to the corresponding record in the unit index. This is required for DW_FORM_loclistx to work. Differential revision: https://reviews.llvm.org/D77146
llvm · Apr 6, 2020 · a93b77b · a93b77b
1 parent 49737df
commit a93b77b
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Showing 2 changed files with 35 additions and 2 deletions.
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp b/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
@@ -538,6 +538,9 @@ Error DWARFUnit::tryExtractDIEsIfNeeded(bool CUDieOnly) {
                                  " list table with base = 0x%" PRIx64 "\n",
                                  Offset);
       Offset -= HeaderSize;
+      if (auto *IndexEntry = Header.getIndexEntry())
+        if (const auto *Contrib = IndexEntry->getContribution(DW_SECT_LOCLISTS))
+          Offset += Contrib->Offset;
       if (Error E = LoclistTableHeader->extract(Data, &Offset))
         return createStringError(errc::invalid_argument,
                                  "parsing a loclist table: " +

diff --git a/llvm/test/DebugInfo/X86/dwp-v5-loclists.s b/llvm/test/DebugInfo/X86/dwp-v5-loclists.s
@@ -12,12 +12,19 @@
 # CHECK-NEXT:   DW_AT_name ("a")
 # CHECK-NEXT:   DW_AT_location (0x{{[0-9a-f]+}}:
 # CHECK-NEXT:     DW_LLE_startx_length (0x0000000000000001, 0x0000000000000010): DW_OP_reg5 RDI)
+# CHECK:      DW_TAG_variable
+# CHECK-NEXT:   DW_AT_name ("b")
+# CHECK-NEXT:   DW_AT_location (indexed (0x1) loclist = 0x{{[0-9a-f]+}}:
+# CHECK-NEXT:     DW_LLE_startx_length (0x0000000000000005, 0x0000000000000020): DW_OP_regx RDI)
 
 # CHECK:      .debug_loclists.dwo contents:
 # CHECK:      locations list header:
 # CHECK:      locations list header:
+# CHECK:      offsets:
 # CHECK:      0x{{[0-9a-f]+}}:
 # CHECK-NEXT:   DW_LLE_startx_length (0x0000000000000001, 0x0000000000000010): DW_OP_reg5 RDI
+# CHECK:      0x{{[0-9a-f]+}}:
+# CHECK-NEXT:   DW_LLE_startx_length (0x0000000000000005, 0x0000000000000020): DW_OP_regx RDI
 
 .section .debug_abbrev.dwo, "e", @progbits
 .LAbbrevBegin:
@@ -35,6 +42,15 @@
     .uleb128 23                         # DW_FORM_sec_offset
     .byte 0                             # EOM(1)
     .byte 0                             # EOM(2)
+    .uleb128 3                          # Abbreviation Code
+    .uleb128 52                         # DW_TAG_variable
+    .byte 0                             # DW_CHILDREN_no
+    .uleb128 3                          # DW_AT_name
+    .uleb128 8                          # DW_FORM_string
+    .uleb128 2                          # DW_AT_location
+    .uleb128 34                         # DW_FORM_loclistx
+    .byte 0                             # EOM(1)
+    .byte 0                             # EOM(2)
     .byte 0                             # EOM(3)
 .LAbbrevEnd:
 
@@ -50,7 +66,10 @@
     .uleb128 1                          # Abbrev [1] DW_TAG_compile_unit
     .uleb128 2                          # Abbrev [2] DW_TAG_variable
     .asciz "a"                          # DW_AT_name
-    .long .LLL0-.LLLBegin               # DW_AT_location
+    .long .LLL0-.LLLBegin               # DW_AT_location (DW_FORM_sec_offset)
+    .uleb128 3                          # Abbrev [3] DW_TAG_variable
+    .asciz "b"                          # DW_AT_name
+    .uleb128 1                          # DW_AT_location (DW_FORM_loclistx)
     .byte 0                             # End Of Children Mark
 .LCUEnd:
 
@@ -72,14 +91,25 @@
     .short 5                            # Version
     .byte 8                             # Address size
     .byte 0                             # Segment selector size
-    .long 0                             # Offset entry count
+    .long 2                             # Offset entry count
+.LLLBase:
+    .long .LLL0-.LLLBase
+    .long .LLL1-.LLLBase
 .LLL0:
     .byte 3                             # DW_LLE_startx_length
     .uleb128 1                          # Index
     .uleb128 0x10                       # Length
     .uleb128 1                          # Loc expr size
     .byte 85                            # DW_OP_reg5
     .byte 0                             # DW_LLE_end_of_list
+.LLL1:
+    .byte 3                             # DW_LLE_startx_length
+    .uleb128 5                          # Index
+    .uleb128 0x20                       # Length
+    .uleb128 2                          # Loc expr size
+    .byte 144                           # DW_OP_regx
+    .uleb128 5                          # RDI
+    .byte 0                             # DW_LLE_end_of_list
 .LLLEnd:
 
     .section .debug_cu_index, "", @progbits