[llvm-commits] [llvm] r122591 - in /llvm/trunk: include/llvm/MC/MCAssembler.h include/llvm/MC/MCDwarf.h include/llvm/MC/MCObjectStreamer.h include/llvm/MC/MCStreamer.h lib/MC/MCAssembler.cpp lib/MC/MCDwarf.cpp lib/MC/MCObjectStreamer.cpp test/MC/ELF/cfi-def-cfa-offset.s
Rafael Espindola
rafael.espindola at gmail.com
Mon Dec 27 21:39:27 PST 2010
Author: rafael
Date: Mon Dec 27 23:39:27 2010
New Revision: 122591
URL: http://llvm.org/viewvc/llvm-project?rev=122591&view=rev
Log:
Relax address updates in the eh_frame section.
Modified:
llvm/trunk/include/llvm/MC/MCAssembler.h
llvm/trunk/include/llvm/MC/MCDwarf.h
llvm/trunk/include/llvm/MC/MCObjectStreamer.h
llvm/trunk/include/llvm/MC/MCStreamer.h
llvm/trunk/lib/MC/MCAssembler.cpp
llvm/trunk/lib/MC/MCDwarf.cpp
llvm/trunk/lib/MC/MCObjectStreamer.cpp
llvm/trunk/test/MC/ELF/cfi-def-cfa-offset.s
Modified: llvm/trunk/include/llvm/MC/MCAssembler.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCAssembler.h?rev=122591&r1=122590&r2=122591&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCAssembler.h (original)
+++ llvm/trunk/include/llvm/MC/MCAssembler.h Mon Dec 27 23:39:27 2010
@@ -52,6 +52,7 @@
FT_Inst,
FT_Org,
FT_Dwarf,
+ FT_DwarfFrame,
FT_LEB
};
@@ -369,7 +370,7 @@
public:
MCDwarfLineAddrFragment(int64_t _LineDelta, const MCExpr &_AddrDelta,
- MCSectionData *SD = 0)
+ MCSectionData *SD)
: MCFragment(FT_Dwarf, SD),
LineDelta(_LineDelta), AddrDelta(&_AddrDelta) { Contents.push_back(0); }
@@ -391,6 +392,34 @@
static bool classof(const MCDwarfLineAddrFragment *) { return true; }
};
+class MCDwarfCallFrameFragment : public MCFragment {
+ /// AddrDelta - The expression for the difference of the two symbols that
+ /// make up the address delta between two .cfi_* dwarf directives.
+ const MCExpr *AddrDelta;
+
+ SmallString<8> Contents;
+
+public:
+ MCDwarfCallFrameFragment(const MCExpr &_AddrDelta, MCSectionData *SD)
+ : MCFragment(FT_DwarfFrame, SD),
+ AddrDelta(&_AddrDelta) { Contents.push_back(0); }
+
+ /// @name Accessors
+ /// @{
+
+ const MCExpr &getAddrDelta() const { return *AddrDelta; }
+
+ SmallString<8> &getContents() { return Contents; }
+ const SmallString<8> &getContents() const { return Contents; }
+
+ /// @}
+
+ static bool classof(const MCFragment *F) {
+ return F->getKind() == MCFragment::FT_DwarfFrame;
+ }
+ static bool classof(const MCDwarfCallFrameFragment *) { return true; }
+};
+
// FIXME: Should this be a separate class, or just merged into MCSection? Since
// we anticipate the fast path being through an MCAssembler, the only reason to
// keep it out is for API abstraction.
@@ -705,6 +734,8 @@
bool RelaxLEB(MCAsmLayout &Layout, MCLEBFragment &IF);
bool RelaxDwarfLineAddr(MCAsmLayout &Layout, MCDwarfLineAddrFragment &DF);
+ bool RelaxDwarfCallFrameFragment(MCAsmLayout &Layout,
+ MCDwarfCallFrameFragment &DF);
/// FinishLayout - Finalize a layout, including fragment lowering.
void FinishLayout(MCAsmLayout &Layout);
Modified: llvm/trunk/include/llvm/MC/MCDwarf.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCDwarf.h?rev=122591&r1=122590&r2=122591&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCDwarf.h (original)
+++ llvm/trunk/include/llvm/MC/MCDwarf.h Mon Dec 27 23:39:27 2010
@@ -25,6 +25,7 @@
namespace llvm {
class MachineMove;
class MCContext;
+ class MCExpr;
class MCSection;
class MCSectionData;
class MCStreamer;
@@ -245,6 +246,8 @@
// This emits the frame info section.
//
static void Emit(MCStreamer &streamer);
+ static void EmitAdvanceLoc(MCStreamer &Streamer, uint64_t AddrDelta);
+ static void EncodeAdvanceLoc(uint64_t AddrDelta, raw_ostream &OS);
};
} // end namespace llvm
Modified: llvm/trunk/include/llvm/MC/MCObjectStreamer.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCObjectStreamer.h?rev=122591&r1=122590&r2=122591&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCObjectStreamer.h (original)
+++ llvm/trunk/include/llvm/MC/MCObjectStreamer.h Mon Dec 27 23:39:27 2010
@@ -71,6 +71,8 @@
virtual void EmitDwarfAdvanceLineAddr(int64_t LineDelta,
const MCSymbol *LastLabel,
const MCSymbol *Label);
+ virtual void EmitDwarfAdvanceFrameAddr(const MCSymbol *LastLabel,
+ const MCSymbol *Label);
virtual void Finish();
/// @}
Modified: llvm/trunk/include/llvm/MC/MCStreamer.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCStreamer.h?rev=122591&r1=122590&r2=122591&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCStreamer.h (original)
+++ llvm/trunk/include/llvm/MC/MCStreamer.h Mon Dec 27 23:39:27 2010
@@ -386,6 +386,10 @@
const MCSymbol *LastLabel,
const MCSymbol *Label) = 0;
+ virtual void EmitDwarfAdvanceFrameAddr(const MCSymbol *LastLabel,
+ const MCSymbol *Label) {
+ }
+
void EmitDwarfSetLineAddr(int64_t LineDelta, const MCSymbol *Label,
int PointerSize);
Modified: llvm/trunk/lib/MC/MCAssembler.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCAssembler.cpp?rev=122591&r1=122590&r2=122591&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCAssembler.cpp (original)
+++ llvm/trunk/lib/MC/MCAssembler.cpp Mon Dec 27 23:39:27 2010
@@ -323,6 +323,8 @@
case MCFragment::FT_Dwarf:
return cast<MCDwarfLineAddrFragment>(F).getContents().size();
+ case MCFragment::FT_DwarfFrame:
+ return cast<MCDwarfCallFrameFragment>(F).getContents().size();
}
assert(0 && "invalid fragment kind");
@@ -453,6 +455,11 @@
OW->WriteBytes(OF.getContents().str());
break;
}
+ case MCFragment::FT_DwarfFrame: {
+ const MCDwarfCallFrameFragment &CF = cast<MCDwarfCallFrameFragment>(F);
+ OW->WriteBytes(CF.getContents().str());
+ break;
+ }
}
assert(OW->getStream().tell() - Start == FragmentSize);
@@ -712,6 +719,21 @@
return OldSize != Data.size();
}
+bool MCAssembler::RelaxDwarfCallFrameFragment(MCAsmLayout &Layout,
+ MCDwarfCallFrameFragment &DF) {
+ int64_t AddrDelta = 0;
+ uint64_t OldSize = DF.getContents().size();
+ bool IsAbs = DF.getAddrDelta().EvaluateAsAbsolute(AddrDelta, Layout);
+ (void)IsAbs;
+ assert(IsAbs);
+ SmallString<8> &Data = DF.getContents();
+ Data.clear();
+ raw_svector_ostream OSE(Data);
+ MCDwarfFrameEmitter::EncodeAdvanceLoc(AddrDelta, OSE);
+ OSE.flush();
+ return OldSize != Data.size();
+}
+
bool MCAssembler::LayoutSectionOnce(MCAsmLayout &Layout,
MCSectionData &SD) {
MCFragment *FirstInvalidFragment = NULL;
@@ -730,9 +752,14 @@
relaxedFrag = RelaxDwarfLineAddr(Layout,
*cast<MCDwarfLineAddrFragment>(it2));
break;
- case MCFragment::FT_LEB:
- relaxedFrag = RelaxLEB(Layout, *cast<MCLEBFragment>(it2));
- break;
+ case MCFragment::FT_DwarfFrame:
+ relaxedFrag =
+ RelaxDwarfCallFrameFragment(Layout,
+ *cast<MCDwarfCallFrameFragment>(it2));
+ break;
+ case MCFragment::FT_LEB:
+ relaxedFrag = RelaxLEB(Layout, *cast<MCLEBFragment>(it2));
+ break;
}
// Update the layout, and remember that we relaxed.
if (relaxedFrag && !FirstInvalidFragment)
@@ -789,6 +816,7 @@
case MCFragment::FT_Inst: OS << "MCInstFragment"; break;
case MCFragment::FT_Org: OS << "MCOrgFragment"; break;
case MCFragment::FT_Dwarf: OS << "MCDwarfFragment"; break;
+ case MCFragment::FT_DwarfFrame: OS << "MCDwarfCallFrameFragment"; break;
case MCFragment::FT_LEB: OS << "MCLEBFragment"; break;
}
@@ -855,6 +883,12 @@
<< " LineDelta:" << OF->getLineDelta();
break;
}
+ case MCFragment::FT_DwarfFrame: {
+ const MCDwarfCallFrameFragment *CF = cast<MCDwarfCallFrameFragment>(this);
+ OS << "\n ";
+ OS << " AddrDelta:" << CF->getAddrDelta();
+ break;
+ }
case MCFragment::FT_LEB: {
const MCLEBFragment *LF = cast<MCLEBFragment>(this);
OS << "\n ";
Modified: llvm/trunk/lib/MC/MCDwarf.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCDwarf.cpp?rev=122591&r1=122590&r2=122591&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCDwarf.cpp (original)
+++ llvm/trunk/lib/MC/MCDwarf.cpp Mon Dec 27 23:39:27 2010
@@ -460,12 +460,7 @@
if (BaseLabel && Label) {
MCSymbol *ThisSym = Label;
if (ThisSym != BaseLabel) {
- // FIXME: We should relax this instead of using a DW_CFA_advance_loc4
- // for every address change!
- streamer.EmitIntValue(dwarf::DW_CFA_advance_loc4, 1);
- const MCExpr *Length = MakeStartMinusEndExpr(streamer, *BaseLabel,
- *ThisSym, 0);
- streamer.EmitValue(Length, 4);
+ streamer.EmitDwarfAdvanceFrameAddr(BaseLabel, ThisSym);
BaseLabel = ThisSym;
}
}
@@ -748,3 +743,30 @@
if (fdeEnd)
streamer.EmitLabel(fdeEnd);
}
+
+void MCDwarfFrameEmitter::EmitAdvanceLoc(MCStreamer &Streamer,
+ uint64_t AddrDelta) {
+ SmallString<256> Tmp;
+ raw_svector_ostream OS(Tmp);
+ MCDwarfFrameEmitter::EncodeAdvanceLoc(AddrDelta, OS);
+ Streamer.EmitBytes(OS.str(), /*AddrSpace=*/0);
+}
+
+void MCDwarfFrameEmitter::EncodeAdvanceLoc(uint64_t AddrDelta,
+ raw_ostream &OS) {
+ // FIXME: Assumes the code alignment factor is 1.
+ if (isUIntN(6, AddrDelta)) {
+ uint8_t Opcode = dwarf::DW_CFA_advance_loc | AddrDelta;
+ OS << Opcode;
+ } else if (isUInt<8>(AddrDelta)) {
+ OS << uint8_t(dwarf::DW_CFA_advance_loc1);
+ OS << uint8_t(AddrDelta);
+ } else if (isUInt<16>(AddrDelta)) {
+ OS << uint8_t(dwarf::DW_CFA_advance_loc2);
+ OS << uint16_t(AddrDelta);
+ } else {
+ assert(isUInt<32>(AddrDelta));
+ OS << uint8_t(dwarf::DW_CFA_advance_loc4);
+ OS << uint32_t(AddrDelta);
+ }
+}
Modified: llvm/trunk/lib/MC/MCObjectStreamer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCObjectStreamer.cpp?rev=122591&r1=122590&r2=122591&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCObjectStreamer.cpp (original)
+++ llvm/trunk/lib/MC/MCObjectStreamer.cpp Mon Dec 27 23:39:27 2010
@@ -190,6 +190,28 @@
getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, IF->getFixups());
}
+static const MCExpr *BuildSymbolDiff(MCContext &Context,
+ const MCSymbol *A, const MCSymbol *B) {
+ MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
+ const MCExpr *ARef =
+ MCSymbolRefExpr::Create(A, Variant, Context);
+ const MCExpr *BRef =
+ MCSymbolRefExpr::Create(B, Variant, Context);
+ const MCExpr *AddrDelta =
+ MCBinaryExpr::Create(MCBinaryExpr::Sub, ARef, BRef, Context);
+ return AddrDelta;
+}
+
+static const MCExpr *ForceExpAbs(MCObjectStreamer *Streamer,
+ MCContext &Context, const MCExpr* Expr) {
+ if (Context.getAsmInfo().hasAggressiveSymbolFolding())
+ return Expr;
+
+ MCSymbol *ABS = Context.CreateTempSymbol();
+ Streamer->EmitAssignment(ABS, Expr);
+ return MCSymbolRefExpr::Create(ABS, Context);
+}
+
void MCObjectStreamer::EmitDwarfAdvanceLineAddr(int64_t LineDelta,
const MCSymbol *LastLabel,
const MCSymbol *Label) {
@@ -198,27 +220,28 @@
EmitDwarfSetLineAddr(LineDelta, Label, PointerSize);
return;
}
- MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
- const MCExpr *LabelRef =
- MCSymbolRefExpr::Create(Label, Variant, getContext());
- const MCExpr *LastLabelRef =
- MCSymbolRefExpr::Create(LastLabel, Variant, getContext());
- const MCExpr *AddrDelta =
- MCBinaryExpr::Create(MCBinaryExpr::Sub, LabelRef, LastLabelRef,
- getContext());
+ const MCExpr *AddrDelta = BuildSymbolDiff(getContext(), Label, LastLabel);
int64_t Res;
if (AddrDelta->EvaluateAsAbsolute(Res, getAssembler())) {
MCDwarfLineAddr::Emit(this, LineDelta, Res);
return;
}
- if (!getContext().getAsmInfo().hasAggressiveSymbolFolding()) {
- MCSymbol *ABS = getContext().CreateTempSymbol();
- EmitAssignment(ABS, AddrDelta);
- AddrDelta = MCSymbolRefExpr::Create(ABS, getContext());
- }
+ AddrDelta = ForceExpAbs(this, getContext(), AddrDelta);
new MCDwarfLineAddrFragment(LineDelta, *AddrDelta, getCurrentSectionData());
}
+void MCObjectStreamer::EmitDwarfAdvanceFrameAddr(const MCSymbol *LastLabel,
+ const MCSymbol *Label) {
+ const MCExpr *AddrDelta = BuildSymbolDiff(getContext(), Label, LastLabel);
+ int64_t Res;
+ if (AddrDelta->EvaluateAsAbsolute(Res, getAssembler())) {
+ MCDwarfFrameEmitter::EmitAdvanceLoc(*this, Res);
+ return;
+ }
+ AddrDelta = ForceExpAbs(this, getContext(), AddrDelta);
+ new MCDwarfCallFrameFragment(*AddrDelta, getCurrentSectionData());
+}
+
void MCObjectStreamer::EmitValueToOffset(const MCExpr *Offset,
unsigned char Value) {
new MCOrgFragment(*Offset, Value, getCurrentSectionData());
Modified: llvm/trunk/test/MC/ELF/cfi-def-cfa-offset.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/ELF/cfi-def-cfa-offset.s?rev=122591&r1=122590&r2=122591&view=diff
==============================================================================
--- llvm/trunk/test/MC/ELF/cfi-def-cfa-offset.s (original)
+++ llvm/trunk/test/MC/ELF/cfi-def-cfa-offset.s Mon Dec 27 23:39:27 2010
@@ -10,21 +10,18 @@
ret
.cfi_endproc
-// FIXME: This is a correct but really inefficient coding since
-// we use a CFA_advance_loc4 for every address change!
-
// CHECK: # Section 0x00000004
// CHECK-NEXT: (('sh_name', 0x00000012) # '.eh_frame'
// CHECK-NEXT: ('sh_type', 0x00000001)
// CHECK-NEXT: ('sh_flags', 0x00000002)
// CHECK-NEXT: ('sh_addr', 0x00000000)
// CHECK-NEXT: ('sh_offset', 0x00000050)
-// CHECK-NEXT: ('sh_size', 0x00000038)
+// CHECK-NEXT: ('sh_size', 0x00000030)
// CHECK-NEXT: ('sh_link', 0x00000000)
// CHECK-NEXT: ('sh_info', 0x00000000)
// CHECK-NEXT: ('sh_addralign', 0x00000008)
// CHECK-NEXT: ('sh_entsize', 0x00000000)
-// CHECK-NEXT: ('_section_data', '14000000 00000000 017a5200 01781001 1b0c0708 90010000 1c000000 1c000000 00000000 0a000000 00040400 00000e10 04050000 000e0800')
+// CHECK-NEXT: ('_section_data', '14000000 00000000 017a5200 01781001 1b0c0708 90010000 14000000 1c000000 00000000 0a000000 00440e10 450e0800')
// CHECK-NEXT: ),
// CHECK: # Section 0x00000008
@@ -32,7 +29,7 @@
// CHECK-NEXT: ('sh_type', 0x00000004)
// CHECK-NEXT: ('sh_flags', 0x00000000)
// CHECK-NEXT: ('sh_addr', 0x00000000)
-// CHECK-NEXT: ('sh_offset', 0x00000168)
+// CHECK-NEXT: ('sh_offset', 0x00000160)
// CHECK-NEXT: ('sh_size', 0x00000018)
// CHECK-NEXT: ('sh_link', 0x00000006)
// CHECK-NEXT: ('sh_info', 0x00000004)
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