Revision: 20715
Author: [email protected]
Date: Mon Apr 14 11:08:14 2014 UTC
Log: ARM64: Avoid iterating through all unresolved branch infos when
many are pending.
Instead, inspect the label chain and delete pending information for every
branch
in the chain.
[email protected]
Review URL: https://codereview.chromium.org/227043010
http://code.google.com/p/v8/source/detail?r=20715
Modified:
/branches/bleeding_edge/src/arm64/assembler-arm64.cc
/branches/bleeding_edge/src/arm64/assembler-arm64.h
/branches/bleeding_edge/src/arm64/instructions-arm64.h
=======================================
--- /branches/bleeding_edge/src/arm64/assembler-arm64.cc Mon Apr 7
12:33:03 2014 UTC
+++ /branches/bleeding_edge/src/arm64/assembler-arm64.cc Mon Apr 14
11:08:14 2014 UTC
@@ -543,6 +543,40 @@
return offset;
}
+
+
+void Assembler::DeleteUnresolvedBranchInfoForLabelTraverse(Label* label) {
+ ASSERT(label->is_linked());
+ CheckLabelLinkChain(label);
+
+ int link_offset = label->pos();
+ int link_pcoffset;
+ bool end_of_chain = false;
+
+ while (!end_of_chain) {
+ Instruction * link = InstructionAt(link_offset);
+ link_pcoffset = link->ImmPCOffset();
+
+ // ADR instructions are not handled by veneers.
+ if (link->IsImmBranch()) {
+ int max_reachable_pc = InstructionOffset(link) +
+ Instruction::ImmBranchRange(link->BranchType());
+ typedef std::multimap<int, FarBranchInfo>::iterator
unresolved_info_it;
+ std::pair<unresolved_info_it, unresolved_info_it> range;
+ range = unresolved_branches_.equal_range(max_reachable_pc);
+ unresolved_info_it it;
+ for (it = range.first; it != range.second; ++it) {
+ if (it->second.pc_offset_ == link_offset) {
+ unresolved_branches_.erase(it);
+ break;
+ }
+ }
+ }
+
+ end_of_chain = (link_pcoffset == 0);
+ link_offset = link_offset + link_pcoffset;
+ }
+}
void Assembler::DeleteUnresolvedBranchInfoForLabel(Label* label) {
@@ -552,16 +586,9 @@
}
if (label->is_linked()) {
- // Branches to this label will be resolved when the label is bound
below.
- std::multimap<int, FarBranchInfo>::iterator it_tmp, it;
- it = unresolved_branches_.begin();
- while (it != unresolved_branches_.end()) {
- it_tmp = it++;
- if (it_tmp->second.label_ == label) {
- CHECK(it_tmp->first >= pc_offset());
- unresolved_branches_.erase(it_tmp);
- }
- }
+ // Branches to this label will be resolved when the label is bound,
normally
+ // just after all the associated info has been deleted.
+ DeleteUnresolvedBranchInfoForLabelTraverse(label);
}
if (unresolved_branches_.empty()) {
next_veneer_pool_check_ = kMaxInt;
=======================================
--- /branches/bleeding_edge/src/arm64/assembler-arm64.h Mon Apr 14 11:04:46
2014 UTC
+++ /branches/bleeding_edge/src/arm64/assembler-arm64.h Mon Apr 14 11:08:14
2014 UTC
@@ -1693,6 +1693,10 @@
Instruction* InstructionAt(int offset) const {
return reinterpret_cast<Instruction*>(buffer_ + offset);
}
+
+ ptrdiff_t InstructionOffset(Instruction* instr) const {
+ return reinterpret_cast<byte*>(instr) - buffer_;
+ }
// Register encoding.
static Instr Rd(CPURegister rd) {
@@ -2183,6 +2187,11 @@
// not later attempt (likely unsuccessfully) to patch it to branch
directly to
// the label.
void DeleteUnresolvedBranchInfoForLabel(Label* label);
+ // This function deletes the information related to the label by
traversing
+ // the label chain, and for each PC-relative instruction in the chain
checking
+ // if pending unresolved information exists. Its complexity is
proportional to
+ // the length of the label chain.
+ void DeleteUnresolvedBranchInfoForLabelTraverse(Label* label);
private:
PositionsRecorder positions_recorder_;
=======================================
--- /branches/bleeding_edge/src/arm64/instructions-arm64.h Mon Apr 7
12:33:03 2014 UTC
+++ /branches/bleeding_edge/src/arm64/instructions-arm64.h Mon Apr 14
11:08:14 2014 UTC
@@ -191,6 +191,10 @@
bool IsTestBranch() const {
return Mask(TestBranchFMask) == TestBranchFixed;
}
+
+ bool IsImmBranch() const {
+ return BranchType() != UnknownBranchType;
+ }
bool IsLdrLiteral() const {
return Mask(LoadLiteralFMask) == LoadLiteralFixed;
--
--
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