Dwarf: support for LTO where a single object file can have multiple line tables
We generate one line table for each compilation unit in the object file.
Reviewed by Eric and Kevin.
rdar://problem/13067005
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174445 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCDwarf.cpp b/lib/MC/MCDwarf.cpp
index 3cf47bc..5465af6 100644
--- a/lib/MC/MCDwarf.cpp
+++ b/lib/MC/MCDwarf.cpp
@@ -101,7 +101,8 @@
}
// Add the line entry to this section's entries.
- LineSection->addLineEntry(LineEntry);
+ LineSection->addLineEntry(LineEntry,
+ MCOS->getContext().getDwarfCompileUnitID());
}
//
@@ -131,7 +132,12 @@
//
static inline void EmitDwarfLineTable(MCStreamer *MCOS,
const MCSection *Section,
- const MCLineSection *LineSection) {
+ const MCLineSection *LineSection,
+ unsigned CUID) {
+ // This LineSection does not contain any LineEntry for the given Compile Unit.
+ if (!LineSection->containEntriesForID(CUID))
+ return;
+
unsigned FileNum = 1;
unsigned LastLine = 1;
unsigned Column = 0;
@@ -141,8 +147,8 @@
// Loop through each MCLineEntry and encode the dwarf line number table.
for (MCLineSection::const_iterator
- it = LineSection->getMCLineEntries()->begin(),
- ie = LineSection->getMCLineEntries()->end(); it != ie; ++it) {
+ it = LineSection->getMCLineEntries(CUID).begin(),
+ ie = LineSection->getMCLineEntries(CUID).end(); it != ie; ++it) {
if (FileNum != it->getFileNum()) {
FileNum = it->getFileNum();
@@ -215,9 +221,36 @@
// Switch to the section where the table will be emitted into.
MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfLineSection());
- // Create a symbol at the beginning of this section.
- MCSymbol *LineStartSym = context.CreateTempSymbol();
- // Set the value of the symbol, as we are at the start of the section.
+ const DenseMap<unsigned, MCSymbol *> &MCLineTableSymbols =
+ MCOS->getContext().getMCLineTableSymbols();
+ // CUID and MCLineTableSymbols are set in DwarfDebug, when DwarfDebug does
+ // not exist, CUID will be 0 and MCLineTableSymbols will be empty.
+ // Handle Compile Unit 0, the line table start symbol is the section symbol.
+ const MCSymbol *LineStartSym = EmitCU(MCOS, 0);
+ // Handle the rest of the Compile Units.
+ for (unsigned Is = 1, Ie = MCLineTableSymbols.size(); Is < Ie; Is++)
+ EmitCU(MCOS, Is);
+
+ // Now delete the MCLineSections that were created in MCLineEntry::Make()
+ // and used to emit the line table.
+ const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
+ MCOS->getContext().getMCLineSections();
+ for (DenseMap<const MCSection *, MCLineSection *>::const_iterator it =
+ MCLineSections.begin(), ie = MCLineSections.end(); it != ie;
+ ++it)
+ delete it->second;
+
+ return LineStartSym;
+}
+
+const MCSymbol *MCDwarfFileTable::EmitCU(MCStreamer *MCOS, unsigned CUID) {
+ MCContext &context = MCOS->getContext();
+
+ // Create a symbol at the beginning of the line table.
+ MCSymbol *LineStartSym = MCOS->getContext().getMCLineTableSymbol(CUID);
+ if (!LineStartSym)
+ LineStartSym = context.CreateTempSymbol();
+ // Set the value of the symbol, as we are at the start of the line table.
MCOS->EmitLabel(LineStartSym);
// Create a symbol for the end of the section (to be set when we get there).
@@ -301,11 +334,7 @@
++it) {
const MCSection *Sec = *it;
const MCLineSection *Line = MCLineSections.lookup(Sec);
- EmitDwarfLineTable(MCOS, Sec, Line);
-
- // Now delete the MCLineSections that were created in MCLineEntry::Make()
- // and used to emit the line table.
- delete Line;
+ EmitDwarfLineTable(MCOS, Sec, Line, CUID);
}
if (MCOS->getContext().getAsmInfo().getLinkerRequiresNonEmptyDwarfLines()