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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Add MacroAssembler::patchableBranch64 and fix ARM64's patchableBranchPtr"
href="https://bugs.webkit.org/show_bug.cgi?id=147761">147761</a>
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<th>Summary</th>
<td>Add MacroAssembler::patchableBranch64 and fix ARM64's patchableBranchPtr
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<th>Classification</th>
<td>Unclassified
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<th>Product</th>
<td>WebKit
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<th>Version</th>
<td>528+ (Nightly build)
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<th>Hardware</th>
<td>Unspecified
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<th>OS</th>
<td>Unspecified
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>Normal
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<th>Priority</th>
<td>P2
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<th>Component</th>
<td>JavaScriptCore
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<th>Assignee</th>
<td>webkit-unassigned@lists.webkit.org
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<th>Reporter</th>
<td>utatane.tea@gmail.com
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<pre>Yup. Currently, there's no patchableBranch64 helper function in MacroAssembler; it can reduce the following
cmp some condition
jump_ok pass
patchable jump
pass:
to
cmp some condition
patchable jump_ng
There's patchableBranchPtr in MacroAssembler under 64bit environments.
However, the current MacroAssemblerARM64's patchableBranchPtr seems wrong.
2344 PatchableJump patchableBranchPtr(RelationalCondition cond, Address left, TrustedImmPtr right = TrustedImmPtr(0))
2345 {
2346 m_makeJumpPatchable = true;
2347 Jump result = branch32(cond, left, TrustedImm32(right));
2348 m_makeJumpPatchable = false;
2349 return PatchableJump(result);
2350 }
It truncate the pointer to imm32. (And there's no patchableBranchPtr user in WebKit currently)</pre>
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