Changes in directory llvm/lib/CodeGen:
DwarfWriter.cpp updated: 1.150 -> 1.151
---
Log message:
Fold the exception actions table harder: if two typeid lists start the
same, only output one copy of the common part.
---
Diffs of the changes: (+68 -56)
DwarfWriter.cpp | 124 ++++++++++++++++++++++++++++++--------------------------
1 files changed, 68 insertions(+), 56 deletions(-)
Index: llvm/lib/CodeGen/DwarfWriter.cpp
diff -u llvm/lib/CodeGen/DwarfWriter.cpp:1.150
llvm/lib/CodeGen/DwarfWriter.cpp:1.151
--- llvm/lib/CodeGen/DwarfWriter.cpp:1.150 Sat Jun 2 11:53:42 2007
+++ llvm/lib/CodeGen/DwarfWriter.cpp Wed Jun 6 10:37:31 2007
@@ -2894,36 +2894,32 @@
O << UsedDirective << EHFrameInfo.FnName << ".eh\n\n";
}
- /// EquivPads - Whether two landing pads have equivalent actions.
- static bool EquivPads(const LandingPadInfo *L, const LandingPadInfo *R) {
- const std::vector<int> &LIds = L->TypeIds;
- const std::vector<int> &RIds = R->TypeIds;
+ /// SharedTypeIds - How many leading type ids two landing pads have in
common.
+ static unsigned SharedTypeIds(const LandingPadInfo *L,
+ const LandingPadInfo *R) {
+ const std::vector<int> &LIds = L->TypeIds, &RIds = R->TypeIds;
unsigned LSize = LIds.size(), RSize = RIds.size();
+ unsigned MinSize = LSize < RSize ? LSize : RSize;
+ unsigned Count = 0;
- if (LSize != RSize)
- return false;
+ for (; Count != MinSize; ++Count)
+ if (LIds[Count] != RIds[Count])
+ return Count;
- for (unsigned i = 0; i != LSize; ++i)
- if (LIds[i] != RIds[i])
- return false;
-
- return true;
+ return Count;
}
- /// PadLT - An order on landing pads, with EquivPads as order equivalence.
+ /// PadLT - Order landing pads lexicographically by type id.
static bool PadLT(const LandingPadInfo *L, const LandingPadInfo *R) {
- const std::vector<int> &LIds = L->TypeIds;
- const std::vector<int> &RIds = R->TypeIds;
+ const std::vector<int> &LIds = L->TypeIds, &RIds = R->TypeIds;
unsigned LSize = LIds.size(), RSize = RIds.size();
+ unsigned MinSize = LSize < RSize ? LSize : RSize;
- if (LSize != RSize)
- return LSize < RSize;
-
- for (unsigned i = 0; i != LSize; ++i)
+ for (unsigned i = 0; i != MinSize; ++i)
if (LIds[i] != RIds[i])
return LIds[i] < RIds[i];
- return false; // Equivalent
+ return LSize < RSize;
}
/// EmitExceptionTable - Emit landpads and actions.
@@ -2960,6 +2956,12 @@
typedef DenseMap<unsigned, PadSite, KeyInfo> PadMapType;
+ struct ActionEntry {
+ int TypeID;
+ int NextAction;
+ struct ActionEntry *Previous;
+ };
+
void EmitExceptionTable() {
// Map all labels and get rid of any dead landing pads.
MMI->TidyLandingPads();
@@ -2977,7 +2979,10 @@
std::sort(LandingPads.begin(), LandingPads.end(), PadLT);
// Gather first action index for each landing pad site.
- SmallVector<unsigned, 32> Actions;
+ SmallVector<unsigned, 32> FirstActions;
+
+ // The actions table.
+ SmallVector<ActionEntry, 64> Actions;
// Compute sizes for exception table.
unsigned SizeSites = 0;
@@ -2985,38 +2990,55 @@
// Look at each landing pad site to compute size. We need the size of each
// landing pad site info and the size of the landing pad's actions.
- signed FirstAction = 0;
+ int FirstAction = 0;
for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
- const LandingPadInfo *LandingPad = LandingPads[i];
+ const LandingPadInfo *LP = LandingPads[i];
+ const std::vector<int> &TypeIds = LP->TypeIds;
+ const unsigned NumShared = i ? SharedTypeIds(LP, LandingPads[i-1]) : 0;
unsigned SizeSiteActions = 0;
- if (!i || !EquivPads(LandingPad, LandingPads[i-1])) {
- const std::vector<int> &TypeIds = LandingPad->TypeIds;
+ if (NumShared < TypeIds.size()) {
unsigned SizeAction = 0;
+ ActionEntry *PrevAction = 0;
- if (TypeIds.empty()) {
- FirstAction = 0;
- } else {
- // Gather the action sizes
- for (unsigned j = 0, M = TypeIds.size(); j != M; ++j) {
- int TypeID = TypeIds[j];
- unsigned SizeTypeID = Asm->SizeSLEB128(TypeID);
- signed Action = j ? -(SizeAction + SizeTypeID) : 0;
- SizeAction = SizeTypeID + Asm->SizeSLEB128(Action);
- SizeSiteActions += SizeAction;
+ if (NumShared) {
+ const unsigned SizePrevIds = LandingPads[i-1]->TypeIds.size();
+ assert(Actions.size());
+ PrevAction = &Actions.back();
+ SizeAction = Asm->SizeSLEB128(PrevAction->NextAction) +
+ Asm->SizeSLEB128(PrevAction->TypeID);
+ for (unsigned j = NumShared; j != SizePrevIds; ++j) {
+ SizeAction -= Asm->SizeSLEB128(PrevAction->TypeID);
+ SizeAction += -PrevAction->NextAction;
+ PrevAction = PrevAction->Previous;
}
+ }
- // Record the first action of the landing pad site.
- FirstAction = SizeActions + SizeSiteActions - SizeAction + 1;
+ // Compute the actions.
+ for (unsigned I = NumShared, M = TypeIds.size(); I != M; ++I) {
+ int TypeID = TypeIds[I];
+ unsigned SizeTypeID = Asm->SizeSLEB128(TypeID);
+
+ int NextAction = SizeAction ? -(SizeAction + SizeTypeID) : 0;
+ SizeAction = SizeTypeID + Asm->SizeSLEB128(NextAction);
+ SizeSiteActions += SizeAction;
+
+ ActionEntry Action = {TypeID, NextAction, PrevAction};
+ Actions.push_back(Action);
+
+ PrevAction = &Actions.back();
}
- } // else re-use previous FirstAction
- Actions.push_back(FirstAction);
+ // Record the first action of the landing pad site.
+ FirstAction = SizeActions + SizeSiteActions - SizeAction + 1;
+ } // else identical - re-use previous FirstAction
+
+ FirstActions.push_back(FirstAction);
// Compute this sites contribution to size.
SizeActions += SizeSiteActions;
- unsigned M = LandingPad->BeginLabels.size();
+ unsigned M = LP->BeginLabels.size();
SizeSites += M*(sizeof(int32_t) + // Site start.
sizeof(int32_t) + // Site length.
sizeof(int32_t) + // Landing pad.
@@ -3111,29 +3133,19 @@
}
Asm->EOL("Landing pad");
- Asm->EmitULEB128Bytes(Actions[P.PadIndex]);
+ Asm->EmitULEB128Bytes(FirstActions[P.PadIndex]);
Asm->EOL("Action");
}
}
// Emit the actions.
- for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
- if (!i || Actions[i] != Actions[i-1]) {
- const LandingPadInfo *LandingPad = LandingPads[i];
- const std::vector<int> &TypeIds = LandingPad->TypeIds;
- unsigned SizeAction = 0;
+ for (unsigned I = 0, N = Actions.size(); I != N; ++I) {
+ ActionEntry &Action = Actions[I];
- for (unsigned j = 0, M = TypeIds.size(); j < M; ++j) {
- int TypeID = TypeIds[j];
- unsigned SizeTypeID = Asm->SizeSLEB128(TypeID);
- Asm->EmitSLEB128Bytes(TypeID);
- Asm->EOL("TypeInfo index");
- signed Action = j ? -(SizeAction + SizeTypeID) : 0;
- SizeAction = SizeTypeID + Asm->SizeSLEB128(Action);
- Asm->EmitSLEB128Bytes(Action);
- Asm->EOL("Next action");
- }
- }
+ Asm->EmitSLEB128Bytes(Action.TypeID);
+ Asm->EOL("TypeInfo index");
+ Asm->EmitSLEB128Bytes(Action.NextAction);
+ Asm->EOL("Next action");
}
// Emit the type ids.
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