[DWARF][NFC] Refactor range list extraction and dumping

The purpose of this patch is twofold: 
- Fold pre-DWARF v5 functionality into v5 to eliminate the need for 2 different 
  versions of range list handling. We get rid of DWARFDebugRangelist{.cpp,.h}.
- Templatize the handling of range list tables so that location list handling
  can take advantage of it as well. Location list and range list tables have the 
  same basic layout.

A non-NFC version of this patch was previously submitted with r342218, but it caused
errors with some TSan tests. This patch has no functional changes. The difference to
the non-NFC patch is that there are no changes to rangelist dumping in this patch.

Differential Revision: https://reviews.llvm.org/D53545

llvm-svn: 345546

1 files changed, 38 insertions, 36 deletions

diff --git a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
index a29c9c2f160..3a0f52753b0 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
@@ -25,7 +25,6 @@
 #include "llvm/DebugInfo/DWARF/DWARFDebugLoc.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugMacro.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugPubTable.h"
-#include "llvm/DebugInfo/DWARF/DWARFDebugRangeList.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugRnglists.h"
 #include "llvm/DebugInfo/DWARF/DWARFDie.h"
 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
@@ -268,26 +267,31 @@ static void dumpAddrSection(raw_ostream &OS, DWARFDataExtractor &AddrData,
   }
 }
 
-// Dump the .debug_rnglists or .debug_rnglists.dwo section (DWARF v5).
+// Dump a section that contains a sequence of tables of lists, such as range
+// or location list tables. In DWARF v5 we expect to find properly formatted
+// tables with headers. In DWARF v4 and earlier we simply expect a sequence of
+// lists, which we treat, mutatis mutandis, like DWARF v5 tables.
+template <typename ListTable>
 static void
-dumpRnglistsSection(raw_ostream &OS, DWARFDataExtractor &rnglistData,
-                    llvm::function_ref<Optional<SectionedAddress>(uint32_t)>
-                        LookupPooledAddress,
-                    DIDumpOptions DumpOpts) {
+dumpListSection(raw_ostream &OS, DWARFContext *C, StringRef SectionName,
+                uint16_t MaxVersion, DWARFDataExtractor &ListData,
+                llvm::function_ref<Optional<SectionedAddress>(uint32_t)>
+                    LookupPooledAddress,
+                DIDumpOptions DumpOpts, bool isDWO = false) {
   uint32_t Offset = 0;
-  while (rnglistData.isValidOffset(Offset)) {
-    llvm::DWARFDebugRnglistTable Rnglists;
-    uint32_t TableOffset = Offset;
-    if (Error Err = Rnglists.extract(rnglistData, &Offset)) {
+  while (ListData.isValidOffset(Offset)) {
+    ListTable Table(C, SectionName, isDWO);
+    if (Error Err = Table.extract(ListData, MaxVersion, &Offset)) {
       WithColor::error() << toString(std::move(Err)) << '\n';
-      uint64_t Length = Rnglists.length();
-      // Keep going after an error, if we can, assuming that the length field
-      // could be read. If it couldn't, stop reading the section.
-      if (Length == 0)
+      // If table extraction set Offset to 0, it indicates that we cannot
+      // continue to read the section.
+      if (Offset == 0)
         break;
-      Offset = TableOffset + Length;
+      // In DWARF v4 and earlier, dump as much of the lists as we can.
+      if (MaxVersion < 5)
+        Table.dump(OS, LookupPooledAddress, DumpOpts);
     } else {
-      Rnglists.dump(OS, LookupPooledAddress, DumpOpts);
+      Table.dump(OS, LookupPooledAddress, DumpOpts);
     }
   }
 }
@@ -508,22 +512,6 @@ void DWARFContext::dump(
     dumpAddrSection(OS, AddrData, DumpOpts, getMaxVersion(), getCUAddrSize());
   }
 
-  if (shouldDump(Explicit, ".debug_ranges", DIDT_ID_DebugRanges,
-                 DObj->getRangeSection().Data)) {
-    uint8_t savedAddressByteSize = getCUAddrSize();
-    DWARFDataExtractor rangesData(*DObj, DObj->getRangeSection(),
-                                  isLittleEndian(), savedAddressByteSize);
-    uint32_t offset = 0;
-    DWARFDebugRangeList rangeList;
-    while (rangesData.isValidOffset(offset)) {
-      if (Error E = rangeList.extract(rangesData, &offset)) {
-        WithColor::error() << toString(std::move(E)) << '\n';
-        break;
-      }
-      rangeList.dump(OS);
-    }
-  }
-
   auto LookupPooledAddress = [&](uint32_t Index) -> Optional<SectionedAddress> {
     const auto &CUs = compile_units();
     auto I = CUs.begin();
@@ -532,18 +520,32 @@ void DWARFContext::dump(
     return (*I)->getAddrOffsetSectionItem(Index);
   };
 
+  if (shouldDump(Explicit, ".debug_ranges", DIDT_ID_DebugRanges,
+                 DObj->getRangeSection().Data)) {
+    uint8_t savedAddressByteSize = getCUAddrSize();
+    DWARFDataExtractor rangesData(*DObj, DObj->getRangeSection(),
+                                  isLittleEndian(), savedAddressByteSize);
+    dumpListSection<DWARFDebugRnglistTable>(OS, this, ".debug_ranges",
+                                            /* MaxVersion = */ 4, rangesData,
+                                            LookupPooledAddress, DumpOpts);
+  }
+
   if (shouldDump(Explicit, ".debug_rnglists", DIDT_ID_DebugRnglists,
                  DObj->getRnglistsSection().Data)) {
     DWARFDataExtractor RnglistData(*DObj, DObj->getRnglistsSection(),
-                                   isLittleEndian(), 0);
-    dumpRnglistsSection(OS, RnglistData, LookupPooledAddress, DumpOpts);
+                                   isLittleEndian(), getCUAddrSize());
+    dumpListSection<DWARFDebugRnglistTable>(OS, this, ".debug_rnglists",
+                                            getMaxVersion(5), RnglistData,
+                                            LookupPooledAddress, DumpOpts);
   }
 
   if (shouldDump(ExplicitDWO, ".debug_rnglists.dwo", DIDT_ID_DebugRnglists,
                  DObj->getRnglistsDWOSection().Data)) {
     DWARFDataExtractor RnglistData(*DObj, DObj->getRnglistsDWOSection(),
-                                   isLittleEndian(), 0);
-    dumpRnglistsSection(OS, RnglistData, LookupPooledAddress, DumpOpts);
+                                   isLittleEndian(), getCUAddrSize());
+    dumpListSection<DWARFDebugRnglistTable>(OS, this, ".debug_rnglists.dwo",
+                                            getMaxVersion(5), RnglistData,
+                                            LookupPooledAddress, DumpOpts);
   }
 
   if (shouldDump(Explicit, ".debug_pubnames", DIDT_ID_DebugPubnames,