From f5dde549cca5193743d11daa1c5f08258bee9d42 Mon Sep 17 00:00:00 2001
From: Jan de Mooij <jdemooij@mozilla.com>
Date: Sat, 3 Jun 2023 05:31:20 +0000
Subject: [PATCH] Bug 1836489 - Remove code and fieldTypes pointers from
CacheIRStubInfo. r=iain
The CacheIR ops and stub field types are stored as trailing arrays, so we can
just compute these values.
Differential Revision: https://phabricator.services.mozilla.com/D179825
---
js/src/jit/CacheIRCompiler.cpp | 2 +-
js/src/jit/CacheIRCompiler.h | 33 +++++++++++++++++++++------------
2 files changed, 22 insertions(+), 13 deletions(-)
diff --git a/js/src/jit/CacheIRCompiler.cpp b/js/src/jit/CacheIRCompiler.cpp
index 51c2d9639b2c7..53b694eee6874 100644
--- a/js/src/jit/CacheIRCompiler.cpp
+++ b/js/src/jit/CacheIRCompiler.cpp
@@ -1358,7 +1358,7 @@ CacheIRStubInfo* CacheIRStubInfo::New(CacheKind kind, ICStubEngine engine,
fieldTypes[numStubFields] = uint8_t(StubField::Type::Limit);
return new (p) CacheIRStubInfo(kind, engine, makesGCCalls, stubDataOffset,
- codeStart, writer.codeLength(), fieldTypes);
+ writer.codeLength());
}
bool OperandLocation::operator==(const OperandLocation& other) const {
diff --git a/js/src/jit/CacheIRCompiler.h b/js/src/jit/CacheIRCompiler.h
index 45066a1b177e2..465db7a9b8ce0 100644
--- a/js/src/jit/CacheIRCompiler.h
+++ b/js/src/jit/CacheIRCompiler.h
@@ -1227,22 +1227,27 @@ class MOZ_RAII AutoAvailableFloatRegister {
// See the 'Sharing Baseline stub code' comment in CacheIR.h for a description
// of this class.
+//
+// CacheIRStubInfo has a trailing variable-length array of bytes. The memory
+// layout is as follows:
+//
+// Item | Offset
+// -----------------+--------------------------------------
+// CacheIRStubInfo | 0
+// CacheIR bytecode | sizeof(CacheIRStubInfo)
+// Stub field types | sizeof(CacheIRStubInfo) + codeLength_
+//
+// The array of stub field types is terminated by StubField::Type::Limit.
class CacheIRStubInfo {
- const uint8_t* code_;
- const uint8_t* fieldTypes_;
- uint32_t length_;
-
+ uint32_t codeLength_;
CacheKind kind_;
ICStubEngine engine_;
uint8_t stubDataOffset_;
bool makesGCCalls_;
CacheIRStubInfo(CacheKind kind, ICStubEngine engine, bool makesGCCalls,
- uint32_t stubDataOffset, const uint8_t* code,
- uint32_t codeLength, const uint8_t* fieldTypes)
- : code_(code),
- fieldTypes_(fieldTypes),
- length_(codeLength),
+ uint32_t stubDataOffset, uint32_t codeLength)
+ : codeLength_(codeLength),
kind_(kind),
engine_(engine),
stubDataOffset_(stubDataOffset),
@@ -1261,14 +1266,18 @@ class CacheIRStubInfo {
ICStubEngine engine() const { return engine_; }
bool makesGCCalls() const { return makesGCCalls_; }
- const uint8_t* code() const { return code_; }
- uint32_t codeLength() const { return length_; }
+ const uint8_t* code() const {
+ return reinterpret_cast<const uint8_t*>(this) + sizeof(CacheIRStubInfo);
+ }
+ uint32_t codeLength() const { return codeLength_; }
uint32_t stubDataOffset() const { return stubDataOffset_; }
size_t stubDataSize() const;
StubField::Type fieldType(uint32_t i) const {
- return (StubField::Type)fieldTypes_[i];
+ static_assert(sizeof(StubField::Type) == sizeof(uint8_t));
+ const uint8_t* fieldTypes = code() + codeLength_;
+ return static_cast<StubField::Type>(fieldTypes[i]);
}
static CacheIRStubInfo* New(CacheKind kind, ICStubEngine engine,
--
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