#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCMachOSymbolFlags.h"
+#include "llvm/MC/MCSectionMachO.h"
+#include "llvm/MC/MCDwarf.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetAsmBackend.h"
private:
void EmitInstToFragment(const MCInst &Inst);
void EmitInstToData(const MCInst &Inst);
+ // FIXME: These will likely moved to a better place.
+ const MCExpr * MakeStartMinusEndExpr(MCSymbol *Start, MCSymbol *End,
+ int IntVal);
+ void EmitDwarfFileTable(void);
public:
MCMachOStreamer(MCContext &Context, TargetAsmBackend &TAB,
EmitInstToFragment(Inst);
}
+//
+// This helper routine returns an expression of End - Start + IntVal for use
+// by EmitDwarfFileTable() below.
+//
+const MCExpr * MCMachOStreamer::MakeStartMinusEndExpr(MCSymbol *Start,
+ MCSymbol *End,
+ int IntVal) {
+ MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
+ const MCExpr *Res =
+ MCSymbolRefExpr::Create(End, Variant, getContext());
+ const MCExpr *RHS =
+ MCSymbolRefExpr::Create(Start, Variant, getContext());
+ const MCExpr *Res1 =
+ MCBinaryExpr::Create(MCBinaryExpr::Sub, Res, RHS,getContext());
+ const MCExpr *Res2 =
+ MCConstantExpr::Create(IntVal, getContext());
+ const MCExpr *Res3 =
+ MCBinaryExpr::Create(MCBinaryExpr::Sub, Res1, Res2, getContext());
+ return Res3;
+}
+
+//
+// This emits the Dwarf file (and eventually the line) table.
+//
+void MCMachOStreamer::EmitDwarfFileTable(void) {
+ // For now make sure we don't put out the Dwarf file table if no .file
+ // directives were seen.
+ const std::vector<MCDwarfFile *> &MCDwarfFiles =
+ getContext().getMCDwarfFiles();
+ if (MCDwarfFiles.size() == 0)
+ return;
+
+ // This is the Mach-O section, for ELF it is the .debug_line section.
+ SwitchSection(getContext().getMachOSection("__DWARF", "__debug_line",
+ MCSectionMachO::S_ATTR_DEBUG,
+ 0, SectionKind::getDataRelLocal()));
+
+ // Create a symbol at the beginning of this section.
+ MCSymbol *LineStartSym = getContext().CreateTempSymbol();
+ // Set the value of the symbol, as we are at the start of the section.
+ EmitLabel(LineStartSym);
+
+ // Create a symbol for the end of the section (to be set when we get there).
+ MCSymbol *LineEndSym = getContext().CreateTempSymbol();
+
+ // The first 4 bytes is the total length of the information for this
+ // compilation unit (not including these 4 bytes for the length).
+ EmitValue(MakeStartMinusEndExpr(LineStartSym, LineEndSym, 4), 4, 0);
+
+ // Next 2 bytes is the Version, which is Dwarf 2.
+ EmitIntValue(2, 2);
+
+ // Create a symbol for the end of the prologue (to be set when we get there).
+ MCSymbol *ProEndSym = getContext().CreateTempSymbol(); // Lprologue_end
+
+ // Length of the prologue, is the next 4 bytes. Which is the start of the
+ // section to the end of the prologue. Not including the 4 bytes for the
+ // total length, the 2 bytes for the version, and these 4 bytes for the
+ // length of the prologue.
+ EmitValue(MakeStartMinusEndExpr(LineStartSym, ProEndSym, (4 + 2 + 4)), 4, 0);
+
+ // Parameters of the state machine, are next.
+ // Define the architecture-dependent minimum instruction length (in
+ // bytes). This value should be rather too small than too big. */
+ // DWARF2_LINE_MIN_INSN_LENGTH
+ EmitIntValue(1, 1);
+ // Flag that indicates the initial value of the is_stmt_start flag.
+ // DWARF2_LINE_DEFAULT_IS_STMT
+ EmitIntValue(1, 1);
+ // Minimum line offset in a special line info. opcode. This value
+ // was chosen to give a reasonable range of values. */
+ // DWARF2_LINE_BASE
+ EmitIntValue(-5, 1);
+ // Range of line offsets in a special line info. opcode.
+ // DWARF2_LINE_RANGE
+ EmitIntValue(14, 1);
+ // First special line opcode - leave room for the standard opcodes.
+ // DWARF2_LINE_OPCODE_BASE
+ EmitIntValue(13, 1);
+
+ // Standard opcode lengths
+ EmitIntValue(0, 1); // length of DW_LNS_copy
+ EmitIntValue(1, 1); // length of DW_LNS_advance_pc
+ EmitIntValue(1, 1); // length of DW_LNS_advance_line
+ EmitIntValue(1, 1); // length of DW_LNS_set_file
+ EmitIntValue(1, 1); // length of DW_LNS_set_column
+ EmitIntValue(0, 1); // length of DW_LNS_negate_stmt
+ EmitIntValue(0, 1); // length of DW_LNS_set_basic_block
+ EmitIntValue(0, 1); // length of DW_LNS_const_add_pc
+ EmitIntValue(1, 1); // length of DW_LNS_fixed_advance_pc
+ EmitIntValue(0, 1); // length of DW_LNS_set_prologue_end
+ EmitIntValue(0, 1); // length of DW_LNS_set_epilogue_begin
+ EmitIntValue(1, 1); // DW_LNS_set_isa
+
+ // Put out the directory and file tables.
+
+ // First the directory table.
+ const std::vector<StringRef> &MCDwarfDirs =
+ getContext().getMCDwarfDirs();
+ for (unsigned i = 0; i < MCDwarfDirs.size(); i++) {
+ EmitBytes(MCDwarfDirs[i], 0); // the DirectoryName
+ EmitBytes(StringRef("\0", 1), 0); // the null termination of the string
+ }
+ EmitIntValue(0, 1); // Terminate the directory list
+
+ // Second the file table.
+ for (unsigned i = 1; i < MCDwarfFiles.size(); i++) {
+ EmitBytes(MCDwarfFiles[i]->getName(), 0); // FileName
+ EmitBytes(StringRef("\0", 1), 0); // the null termination of the string
+ // FIXME the Directory number should be a .uleb128 not a .byte
+ EmitIntValue(MCDwarfFiles[i]->getDirIndex(), 1);
+ EmitIntValue(0, 1); // last modification timestamp (always 0)
+ EmitIntValue(0, 1); // filesize (always 0)
+ }
+ EmitIntValue(0, 1); // Terminate the file list
+
+ // This is the end of the prologue, so set the value of the symbol at the
+ // end of the prologue (that was used in a previous expression).
+ EmitLabel(ProEndSym);
+
+ // TODO: This is the point where the line tables would be emitted.
+
+ // If there are no line tables emited then we emit:
+ // The following DW_LNE_set_address sequence to set the address to zero
+ // TODO test for 32-bit or 64-bit output
+ // This is the sequence for 32-bit code
+ EmitIntValue(0, 1);
+ EmitIntValue(5, 1);
+ EmitIntValue(2, 1);
+ EmitIntValue(0, 1);
+ EmitIntValue(0, 1);
+ EmitIntValue(0, 1);
+ EmitIntValue(0, 1);
+
+ // Lastly emit the DW_LNE_end_sequence which consists of 3 bytes '00 01 01'
+ // (00 is the code for extended opcodes, followed by a ULEB128 length of the
+ // extended opcode (01), and the DW_LNE_end_sequence (01).
+ EmitIntValue(0, 1); // DW_LNS_extended_op
+ EmitIntValue(1, 1); // ULEB128 length of the extended opcode
+ EmitIntValue(1, 1); // DW_LNE_end_sequence
+
+ // This is the end of the section, so set the value of the symbol at the end
+ // of this section (that was used in a previous expression).
+ EmitLabel(LineEndSym);
+}
+
void MCMachOStreamer::Finish() {
+ // Dump out the dwarf file and directory tables (soon to include line table)
+ EmitDwarfFileTable();
+
// We have to set the fragment atom associations so we can relax properly for
// Mach-O.