[Codegen] - Implement basic .debug_loclists section emission (DWARF5).
.debug_loclists is the DWARF 5 version of the .debug_loc.
With that patch, it will be emitted when DWARF 5 is used.
Differential revision: https://reviews.llvm.org/D53365
llvm-svn: 345377
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 4a9ed6d..3a1e548 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -727,11 +727,16 @@
(useSplitDwarf() ? SkeletonHolder : InfoHolder)
.setStringOffsetsStartSym(Asm->createTempSymbol("str_offsets_base"));
- // Create the symbol that designates the start of the DWARF v5 range list
- // table. It is located past the header and before the offsets table.
+
+ // Create the symbols that designates the start of the DWARF v5 range list
+ // and locations list tables. They are located past the table headers.
if (getDwarfVersion() >= 5) {
- (useSplitDwarf() ? SkeletonHolder : InfoHolder)
- .setRnglistsTableBaseSym(Asm->createTempSymbol("rnglists_table_base"));
+ DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
+ Holder.setRnglistsTableBaseSym(
+ Asm->createTempSymbol("rnglists_table_base"));
+ Holder.setLoclistsTableBaseSym(
+ Asm->createTempSymbol("loclists_table_base"));
+
if (useSplitDwarf())
InfoHolder.setRnglistsTableBaseSym(
Asm->createTempSymbol("rnglists_dwo_table_base"));
@@ -889,8 +894,13 @@
U.attachRangesOrLowHighPC(U.getUnitDie(), TheCU.takeRanges());
}
- if (getDwarfVersion() >= 5 && U.hasRangeLists())
- U.addRnglistsBase();
+ if (getDwarfVersion() >= 5) {
+ if (U.hasRangeLists())
+ U.addRnglistsBase();
+
+ if (!DebugLocs.getLists().empty() && !useSplitDwarf())
+ U.addLoclistsBase();
+ }
auto *CUNode = cast<DICompileUnit>(P.first);
// If compile Unit has macros, emit "DW_AT_macro_info" attribute.
@@ -1925,25 +1935,119 @@
emitDebugLocEntry(Streamer, Entry);
}
-// Emit locations into the debug loc section.
+// Emit the common part of the DWARF 5 range/locations list tables header.
+static void emitListsTableHeaderStart(AsmPrinter *Asm, const DwarfFile &Holder,
+ MCSymbol *TableStart,
+ MCSymbol *TableEnd) {
+ // Build the table header, which starts with the length field.
+ Asm->OutStreamer->AddComment("Length");
+ Asm->EmitLabelDifference(TableEnd, TableStart, 4);
+ Asm->OutStreamer->EmitLabel(TableStart);
+ // Version number (DWARF v5 and later).
+ Asm->OutStreamer->AddComment("Version");
+ Asm->emitInt16(Asm->OutStreamer->getContext().getDwarfVersion());
+ // Address size.
+ Asm->OutStreamer->AddComment("Address size");
+ Asm->emitInt8(Asm->MAI->getCodePointerSize());
+ // Segment selector size.
+ Asm->OutStreamer->AddComment("Segment selector size");
+ Asm->emitInt8(0);
+}
+
+// Emit the header of a DWARF 5 range list table list table. Returns the symbol
+// that designates the end of the table for the caller to emit when the table is
+// complete.
+static MCSymbol *emitRnglistsTableHeader(AsmPrinter *Asm,
+ const DwarfFile &Holder) {
+ MCSymbol *TableStart = Asm->createTempSymbol("debug_rnglist_table_start");
+ MCSymbol *TableEnd = Asm->createTempSymbol("debug_rnglist_table_end");
+ emitListsTableHeaderStart(Asm, Holder, TableStart, TableEnd);
+
+ Asm->OutStreamer->AddComment("Offset entry count");
+ Asm->emitInt32(Holder.getRangeLists().size());
+ Asm->OutStreamer->EmitLabel(Holder.getRnglistsTableBaseSym());
+
+ for (const RangeSpanList &List : Holder.getRangeLists())
+ Asm->EmitLabelDifference(List.getSym(), Holder.getRnglistsTableBaseSym(),
+ 4);
+
+ return TableEnd;
+}
+
+// Emit the header of a DWARF 5 locations list table. Returns the symbol that
+// designates the end of the table for the caller to emit when the table is
+// complete.
+static MCSymbol *emitLoclistsTableHeader(AsmPrinter *Asm,
+ const DwarfFile &Holder) {
+ MCSymbol *TableStart = Asm->createTempSymbol("debug_loclist_table_start");
+ MCSymbol *TableEnd = Asm->createTempSymbol("debug_loclist_table_end");
+ emitListsTableHeaderStart(Asm, Holder, TableStart, TableEnd);
+
+ // FIXME: Generate the offsets table and use DW_FORM_loclistx with the
+ // DW_AT_loclists_base attribute. Until then set the number of offsets to 0.
+ Asm->OutStreamer->AddComment("Offset entry count");
+ Asm->emitInt32(0);
+ Asm->OutStreamer->EmitLabel(Holder.getLoclistsTableBaseSym());
+
+ return TableEnd;
+}
+
+// Emit locations into the .debug_loc/.debug_rnglists section.
void DwarfDebug::emitDebugLoc() {
if (DebugLocs.getLists().empty())
return;
- // Start the dwarf loc section.
- Asm->OutStreamer->SwitchSection(
- Asm->getObjFileLowering().getDwarfLocSection());
+ bool IsLocLists = getDwarfVersion() >= 5;
+ MCSymbol *TableEnd = nullptr;
+ if (IsLocLists) {
+ Asm->OutStreamer->SwitchSection(
+ Asm->getObjFileLowering().getDwarfLoclistsSection());
+ TableEnd = emitLoclistsTableHeader(Asm, useSplitDwarf() ? SkeletonHolder
+ : InfoHolder);
+ } else {
+ Asm->OutStreamer->SwitchSection(
+ Asm->getObjFileLowering().getDwarfLocSection());
+ }
+
unsigned char Size = Asm->MAI->getCodePointerSize();
for (const auto &List : DebugLocs.getLists()) {
Asm->OutStreamer->EmitLabel(List.Label);
+
const DwarfCompileUnit *CU = List.CU;
+ const MCSymbol *Base = CU->getBaseAddress();
for (const auto &Entry : DebugLocs.getEntries(List)) {
- // Set up the range. This range is relative to the entry point of the
- // compile unit. This is a hard coded 0 for low_pc when we're emitting
- // ranges, or the DW_AT_low_pc on the compile unit otherwise.
- if (auto *Base = CU->getBaseAddress()) {
- Asm->EmitLabelDifference(Entry.BeginSym, Base, Size);
- Asm->EmitLabelDifference(Entry.EndSym, Base, Size);
+ if (Base) {
+ // Set up the range. This range is relative to the entry point of the
+ // compile unit. This is a hard coded 0 for low_pc when we're emitting
+ // ranges, or the DW_AT_low_pc on the compile unit otherwise.
+ if (IsLocLists) {
+ Asm->OutStreamer->AddComment("DW_LLE_offset_pair");
+ Asm->OutStreamer->EmitIntValue(dwarf::DW_LLE_offset_pair, 1);
+ Asm->OutStreamer->AddComment(" starting offset");
+ Asm->EmitLabelDifferenceAsULEB128(Entry.BeginSym, Base);
+ Asm->OutStreamer->AddComment(" ending offset");
+ Asm->EmitLabelDifferenceAsULEB128(Entry.EndSym, Base);
+ } else {
+ Asm->EmitLabelDifference(Entry.BeginSym, Base, Size);
+ Asm->EmitLabelDifference(Entry.EndSym, Base, Size);
+ }
+
+ emitDebugLocEntryLocation(Entry);
+ continue;
+ }
+
+ // We have no base address.
+ if (IsLocLists) {
+ // TODO: Use DW_LLE_base_addressx + DW_LLE_offset_pair, or
+ // DW_LLE_startx_length in case if there is only a single range.
+ // That should reduce the size of the debug data emited.
+ // For now just use the DW_LLE_startx_length for all cases.
+ Asm->OutStreamer->AddComment("DW_LLE_startx_length");
+ Asm->emitInt8(dwarf::DW_LLE_startx_length);
+ Asm->OutStreamer->AddComment(" start idx");
+ Asm->EmitULEB128(AddrPool.getIndex(Entry.BeginSym));
+ Asm->OutStreamer->AddComment(" length");
+ Asm->EmitLabelDifferenceAsULEB128(Entry.EndSym, Entry.BeginSym);
} else {
Asm->OutStreamer->EmitSymbolValue(Entry.BeginSym, Size);
Asm->OutStreamer->EmitSymbolValue(Entry.EndSym, Size);
@@ -1951,9 +2055,20 @@
emitDebugLocEntryLocation(Entry);
}
- Asm->OutStreamer->EmitIntValue(0, Size);
- Asm->OutStreamer->EmitIntValue(0, Size);
+
+ if (IsLocLists) {
+ // .debug_loclists section ends with DW_LLE_end_of_list.
+ Asm->OutStreamer->AddComment("DW_LLE_end_of_list");
+ Asm->OutStreamer->EmitIntValue(dwarf::DW_LLE_end_of_list, 1);
+ } else {
+ // Terminate the .debug_loc list with two 0 values.
+ Asm->OutStreamer->EmitIntValue(0, Size);
+ Asm->OutStreamer->EmitIntValue(0, Size);
+ }
}
+
+ if (TableEnd)
+ Asm->OutStreamer->EmitLabel(TableEnd);
}
void DwarfDebug::emitDebugLocDWO() {
@@ -2232,39 +2347,6 @@
}
}
-// Emit the header of a DWARF 5 range list table. Returns the symbol that
-// designates the end of the table for the caller to emit when the table is
-// complete.
-static MCSymbol *emitRnglistsTableHeader(AsmPrinter *Asm,
- const DwarfFile &Holder) {
- // The length is described by a starting label right after the length field
- // and an end label.
- MCSymbol *TableStart = Asm->createTempSymbol("debug_rnglist_table_start");
- MCSymbol *TableEnd = Asm->createTempSymbol("debug_rnglist_table_end");
- // Build the range table header, which starts with the length field.
- Asm->OutStreamer->AddComment("Length");
- Asm->EmitLabelDifference(TableEnd, TableStart, 4);
- Asm->OutStreamer->EmitLabel(TableStart);
- // Version number (DWARF v5 and later).
- Asm->OutStreamer->AddComment("Version");
- Asm->emitInt16(Asm->OutStreamer->getContext().getDwarfVersion());
- Asm->OutStreamer->AddComment("Address size");
- Asm->emitInt8(Asm->MAI->getCodePointerSize());
- Asm->OutStreamer->AddComment("Segment selector size");
- Asm->emitInt8(0);
-
- MCSymbol *RnglistsTableBaseSym = Holder.getRnglistsTableBaseSym();
-
- // FIXME: Generate the offsets table and use DW_FORM_rnglistx with the
- // DW_AT_ranges attribute. Until then set the number of offsets to 0.
- Asm->OutStreamer->AddComment("Offset entry count");
- Asm->emitInt32(Holder.getRangeLists().size());
- Asm->OutStreamer->EmitLabel(RnglistsTableBaseSym);
- for (const RangeSpanList &List : Holder.getRangeLists())
- Asm->EmitLabelDifference(List.getSym(), RnglistsTableBaseSym, 4);
- return TableEnd;
-}
-
void emitDebugRangesImpl(DwarfDebug &DD, AsmPrinter *Asm,
const DwarfFile &Holder, MCSymbol *TableEnd) {
for (const RangeSpanList &List : Holder.getRangeLists())
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfFile.h b/llvm/lib/CodeGen/AsmPrinter/DwarfFile.h
index c764c6c..1e5c99e 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfFile.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfFile.h
@@ -89,6 +89,10 @@
/// The table is shared by all units.
MCSymbol *RnglistsTableBaseSym = nullptr;
+ /// DWARF v5: The symbol that designates the base of the locations list table.
+ /// The table is shared by all units.
+ MCSymbol *LoclistsTableBaseSym = nullptr;
+
/// The variables of a lexical scope.
struct ScopeVars {
/// We need to sort Args by ArgNo and check for duplicates. This could also
@@ -161,13 +165,14 @@
DwarfStringPool &getStringPool() { return StrPool; }
MCSymbol *getStringOffsetsStartSym() const { return StringOffsetsStartSym; }
-
void setStringOffsetsStartSym(MCSymbol *Sym) { StringOffsetsStartSym = Sym; }
MCSymbol *getRnglistsTableBaseSym() const { return RnglistsTableBaseSym; }
-
void setRnglistsTableBaseSym(MCSymbol *Sym) { RnglistsTableBaseSym = Sym; }
+ MCSymbol *getLoclistsTableBaseSym() const { return LoclistsTableBaseSym; }
+ void setLoclistsTableBaseSym(MCSymbol *Sym) { LoclistsTableBaseSym = Sym; }
+
/// \returns false if the variable was merged with a previous one.
bool addScopeVariable(LexicalScope *LS, DbgVariable *Var);
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index 42aa0c9..2053395 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -1656,6 +1656,15 @@
TLOF.getDwarfRnglistsSection()->getBeginSymbol());
}
+void DwarfUnit::addLoclistsBase() {
+ assert(DD->getDwarfVersion() >= 5 &&
+ "DW_AT_loclists_base requires DWARF version 5 or later");
+ const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
+ addSectionLabel(getUnitDie(), dwarf::DW_AT_loclists_base,
+ DU->getLoclistsTableBaseSym(),
+ TLOF.getDwarfLoclistsSection()->getBeginSymbol());
+}
+
void DwarfUnit::addAddrTableBase() {
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
MCSymbol *Label = DD->getAddressPool().getLabel();
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
index 1a36ea9..860d165 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
@@ -272,6 +272,9 @@
/// Add the DW_AT_rnglists_base attribute to the unit DIE.
void addRnglistsBase();
+ /// Add the DW_AT_loclists_base attribute to the unit DIE.
+ void addLoclistsBase();
+
/// Add the DW_AT_addr_base attribute to the unit DIE.
void addAddrTableBase();