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-rw-r--r--include/llvm/MC/MCAsmLayout.h4
-rw-r--r--include/llvm/MC/MCAssembler.h25
-rw-r--r--lib/MC/MCAssembler.cpp55
-rw-r--r--test/MC/MachO/relax-recompute-align.s10
4 files changed, 46 insertions, 48 deletions
diff --git a/include/llvm/MC/MCAsmLayout.h b/include/llvm/MC/MCAsmLayout.h
index 64b0b4e026..7ea0bac0f7 100644
--- a/include/llvm/MC/MCAsmLayout.h
+++ b/include/llvm/MC/MCAsmLayout.h
@@ -76,10 +76,6 @@ public:
/// @name Fragment Layout Data
/// @{
- /// \brief Get the effective size of the given fragment, as computed in the
- /// current layout.
- uint64_t getFragmentEffectiveSize(const MCFragment *F) const;
-
/// \brief Get the offset of the given fragment inside its containing section.
uint64_t getFragmentOffset(const MCFragment *F) const;
diff --git a/include/llvm/MC/MCAssembler.h b/include/llvm/MC/MCAssembler.h
index ea250045ad..19d8ea5d09 100644
--- a/include/llvm/MC/MCAssembler.h
+++ b/include/llvm/MC/MCAssembler.h
@@ -75,10 +75,6 @@ private:
/// initialized.
uint64_t Offset;
- /// EffectiveSize - The compute size of this section. This is ~0 until
- /// initialized.
- uint64_t EffectiveSize;
-
/// LayoutOrder - The layout order of this fragment.
unsigned LayoutOrder;
@@ -231,6 +227,9 @@ class MCAlignFragment : public MCFragment {
/// cannot be satisfied in this width then this fragment is ignored.
unsigned MaxBytesToEmit;
+ /// Size - The current estimate of the size.
+ unsigned Size;
+
/// EmitNops - Flag to indicate that (optimal) NOPs should be emitted instead
/// of using the provided value. The exact interpretation of this flag is
/// target dependent.
@@ -241,7 +240,7 @@ public:
unsigned _MaxBytesToEmit, MCSectionData *SD = 0)
: MCFragment(FT_Align, SD), Alignment(_Alignment),
Value(_Value),ValueSize(_ValueSize),
- MaxBytesToEmit(_MaxBytesToEmit), EmitNops(false) {}
+ MaxBytesToEmit(_MaxBytesToEmit), Size(0), EmitNops(false) {}
/// @name Accessors
/// @{
@@ -252,6 +251,10 @@ public:
unsigned getValueSize() const { return ValueSize; }
+ unsigned getSize() const { return Size; }
+
+ void setSize(unsigned Size_) { Size = Size_; }
+
unsigned getMaxBytesToEmit() const { return MaxBytesToEmit; }
bool hasEmitNops() const { return EmitNops; }
@@ -704,11 +707,6 @@ private:
const MCInstFragment *IF,
const MCAsmLayout &Layout) const;
- /// Compute the effective fragment size assuming it is layed out at the given
- /// \arg SectionAddress and \arg FragmentOffset.
- uint64_t ComputeFragmentSize(const MCFragment &F,
- uint64_t FragmentOffset) const;
-
/// LayoutOnce - Perform one layout iteration and return true if any offsets
/// were adjusted.
bool LayoutOnce(const MCObjectWriter &Writer, MCAsmLayout &Layout);
@@ -725,6 +723,9 @@ private:
bool RelaxDwarfLineAddr(const MCObjectWriter &Writer, MCAsmLayout &Layout,
MCDwarfLineAddrFragment &DF);
+ bool RelaxAlignment(const MCObjectWriter &Writer, MCAsmLayout &Layout,
+ MCAlignFragment &DF);
+
/// FinishLayout - Finalize a layout, including fragment lowering.
void FinishLayout(MCAsmLayout &Layout);
@@ -732,6 +733,10 @@ private:
MCFragment &F, const MCFixup &Fixup);
public:
+ /// Compute the effective fragment size assuming it is layed out at the given
+ /// \arg SectionAddress and \arg FragmentOffset.
+ uint64_t ComputeFragmentSize(const MCFragment &F) const;
+
/// Find the symbol which defines the atom containing the given symbol, or
/// null if there is no such symbol.
const MCSymbolData *getAtom(const MCSymbolData *Symbol) const;
diff --git a/lib/MC/MCAssembler.cpp b/lib/MC/MCAssembler.cpp
index f05f6acd63..0fbd77c7f1 100644
--- a/lib/MC/MCAssembler.cpp
+++ b/lib/MC/MCAssembler.cpp
@@ -74,10 +74,9 @@ void MCAsmLayout::Invalidate(MCFragment *F) {
if (!isFragmentUpToDate(F))
return;
- // Otherwise, reset the last valid fragment to the predecessor of the
- // invalidated fragment.
+ // Otherwise, reset the last valid fragment to this fragment.
const MCSectionData &SD = *F->getParent();
- LastValidFragment[&SD] = F->getPrevNode();
+ LastValidFragment[&SD] = F;
}
void MCAsmLayout::EnsureValid(const MCFragment *F) const {
@@ -96,12 +95,6 @@ void MCAsmLayout::EnsureValid(const MCFragment *F) const {
}
}
-uint64_t MCAsmLayout::getFragmentEffectiveSize(const MCFragment *F) const {
- EnsureValid(F);
- assert(F->EffectiveSize != ~UINT64_C(0) && "Address not set!");
- return F->EffectiveSize;
-}
-
uint64_t MCAsmLayout::getFragmentOffset(const MCFragment *F) const {
EnsureValid(F);
assert(F->Offset != ~UINT64_C(0) && "Address not set!");
@@ -116,7 +109,7 @@ uint64_t MCAsmLayout::getSymbolOffset(const MCSymbolData *SD) const {
uint64_t MCAsmLayout::getSectionAddressSize(const MCSectionData *SD) const {
// The size is the last fragment's end offset.
const MCFragment &F = SD->getFragmentList().back();
- return getFragmentOffset(&F) + getFragmentEffectiveSize(&F);
+ return getFragmentOffset(&F) + getAssembler().ComputeFragmentSize(F);
}
uint64_t MCAsmLayout::getSectionFileSize(const MCSectionData *SD) const {
@@ -137,8 +130,7 @@ MCFragment::~MCFragment() {
}
MCFragment::MCFragment(FragmentType _Kind, MCSectionData *_Parent)
- : Kind(_Kind), Parent(_Parent), Atom(0), Offset(~UINT64_C(0)),
- EffectiveSize(~UINT64_C(0))
+ : Kind(_Kind), Parent(_Parent), Atom(0), Offset(~UINT64_C(0))
{
if (Parent)
Parent->getFragmentList().push_back(this);
@@ -276,8 +268,7 @@ bool MCAssembler::EvaluateFixup(const MCObjectWriter &Writer,
return IsResolved;
}
-uint64_t MCAssembler::ComputeFragmentSize(const MCFragment &F,
- uint64_t FragmentOffset) const {
+uint64_t MCAssembler::ComputeFragmentSize(const MCFragment &F) const {
switch (F.getKind()) {
case MCFragment::FT_Data:
return cast<MCDataFragment>(F).getContents().size();
@@ -289,17 +280,8 @@ uint64_t MCAssembler::ComputeFragmentSize(const MCFragment &F,
case MCFragment::FT_LEB:
return cast<MCLEBFragment>(F).getContents().size();
- case MCFragment::FT_Align: {
- const MCAlignFragment &AF = cast<MCAlignFragment>(F);
-
- uint64_t Size = OffsetToAlignment(FragmentOffset, AF.getAlignment());
-
- // Honor MaxBytesToEmit.
- if (Size > AF.getMaxBytesToEmit())
- return 0;
-
- return Size;
- }
+ case MCFragment::FT_Align:
+ return cast<MCAlignFragment>(F).getSize();
case MCFragment::FT_Org:
return cast<MCOrgFragment>(F).getSize();
@@ -327,10 +309,9 @@ void MCAsmLayout::LayoutFragment(MCFragment *F) {
// Compute fragment offset and size.
uint64_t Offset = 0;
if (Prev)
- Offset += Prev->Offset + Prev->EffectiveSize;
+ Offset += Prev->Offset + getAssembler().ComputeFragmentSize(*Prev);
F->Offset = Offset;
- F->EffectiveSize = getAssembler().ComputeFragmentSize(*F, F->Offset);
LastValidFragment[F->getParent()] = F;
}
@@ -343,7 +324,7 @@ static void WriteFragmentData(const MCAssembler &Asm, const MCAsmLayout &Layout,
++stats::EmittedFragments;
// FIXME: Embed in fragments instead?
- uint64_t FragmentSize = Layout.getFragmentEffectiveSize(&F);
+ uint64_t FragmentSize = Asm.ComputeFragmentSize(F);
switch (F.getKind()) {
case MCFragment::FT_Align: {
MCAlignFragment &AF = cast<MCAlignFragment>(F);
@@ -730,6 +711,18 @@ bool MCAssembler::RelaxDwarfLineAddr(const MCObjectWriter &Writer,
return OldSize != Data.size();
}
+bool MCAssembler::RelaxAlignment(const MCObjectWriter &Writer,
+ MCAsmLayout &Layout,
+ MCAlignFragment &AF) {
+ unsigned Offset = Layout.getFragmentOffset(&AF);
+ unsigned Size = OffsetToAlignment(Offset, AF.getAlignment());
+ if (Size > AF.getMaxBytesToEmit())
+ Size = 0;
+ unsigned OldSize = AF.getSize();
+ AF.setSize(Size);
+ return OldSize != Size;
+}
+
bool MCAssembler::LayoutOnce(const MCObjectWriter &Writer,
MCAsmLayout &Layout) {
++stats::RelaxationSteps;
@@ -747,6 +740,10 @@ bool MCAssembler::LayoutOnce(const MCObjectWriter &Writer,
switch(it2->getKind()) {
default:
break;
+ case MCFragment::FT_Align:
+ relaxedFrag = RelaxAlignment(Writer, Layout,
+ *cast<MCAlignFragment>(it2));
+ break;
case MCFragment::FT_Inst:
relaxedFrag = RelaxInstruction(Writer, Layout,
*cast<MCInstFragment>(it2));
@@ -809,7 +806,7 @@ void MCFragment::dump() {
}
OS << "<MCFragment " << (void*) this << " LayoutOrder:" << LayoutOrder
- << " Offset:" << Offset << " EffectiveSize:" << EffectiveSize << ">";
+ << " Offset:" << Offset << ">";
switch (getKind()) {
case MCFragment::FT_Align: {
diff --git a/test/MC/MachO/relax-recompute-align.s b/test/MC/MachO/relax-recompute-align.s
index b9734cebf3..249402502f 100644
--- a/test/MC/MachO/relax-recompute-align.s
+++ b/test/MC/MachO/relax-recompute-align.s
@@ -3,16 +3,16 @@
// FIXME: This is a horrible way of checking the output, we need an llvm-mc
// based 'otool'.
-// FIXME: PR8467.
-// There is an unnecessary relaxation here. After the first jmp slides,
-// the .align size could be recomputed so that the second jump will be in range
-// for a 1-byte jump. For performance reasons, this is not currently done.
+// This is a case where llvm-mc computes a better layout than Darwin 'as'. This
+// issue is that after the first jmp slides, the .align size must be
+// recomputed -- otherwise the second jump will appear to be out-of-range for a
+// 1-byte jump.
// CHECK: # Section 0
// CHECK: (('section_name', '__text\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
// CHECK: ('segment_name', '__TEXT\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
// CHECK: ('address', 0)
-// CHECK: ('size', 322)
+// CHECK: ('size', 306)
// CHECK: ('offset', 324)
// CHECK: ('alignment', 4)
// CHECK: ('reloc_offset', 0)
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2025-06-27 08:47:32 +0000