Remove branch compaction #ifdef

Since the #ifdef for ARMv7 and ARM64 makes it impossible to cross
compile, we need to replace it with a template specialization of
LinkBuffer. The "old" LinkBuffer becomes LinkBufferBase, then there's a
generic LinkBuffer that's a sub-class of LinkBufferBase. Then there's a
BranchCompactingLinkBuffer template that implements the compaction and
two ARMv7 and ARM64 specializations of LinkBuffer<T> end up being
sub-classes of BranchCompactingLinkBuffer instead of LinkBufferBase.

Change-Id: Ib62fe24aa6c3570dfa311edc39fde6fb5975f3cc
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

9 files changed, 155 insertions, 64 deletions

diff --git a/src/3rdparty/masm/assembler/AbstractMacroAssembler.h b/src/3rdparty/masm/assembler/AbstractMacroAssembler.h
index ea91a99b08..a9035efed7 100644
--- a/src/3rdparty/masm/assembler/AbstractMacroAssembler.h
+++ b/src/3rdparty/masm/assembler/AbstractMacroAssembler.h
@@ -47,8 +47,10 @@
 namespace JSC {
 
 class JumpReplacementWatchpoint;
+template <typename, template <typename> class>
+class LinkBufferBase;
 template <typename>
-class LinkBuffer;
+class BranchCompactingLinkBuffer;
 class RepatchBuffer;
 class Watchpoint;
 namespace DFG {
@@ -326,7 +328,7 @@ public:
         friend class Jump;
         friend class JumpReplacementWatchpoint;
         friend class MacroAssemblerCodeRef;
-        template <typename> friend class LinkBuffer;
+        template <typename, template <typename> class> friend class LinkBufferBase;
         friend class Watchpoint;
 
     public:
@@ -357,7 +359,7 @@ public:
     class ConvertibleLoadLabel {
         template<class TemplateAssemblerType>
         friend class AbstractMacroAssembler;
-        template <typename> friend class LinkBuffer;
+        template <typename, template <typename> class> friend class LinkBufferBase;
         
     public:
         ConvertibleLoadLabel()
@@ -381,7 +383,7 @@ public:
     class DataLabelPtr {
         template<class TemplateAssemblerType>
         friend class AbstractMacroAssembler;
-        template <typename> friend class LinkBuffer;
+        template <typename, template <typename> class> friend class LinkBufferBase;
     public:
         DataLabelPtr()
         {
@@ -405,7 +407,7 @@ public:
     class DataLabel32 {
         template<class TemplateAssemblerType>
         friend class AbstractMacroAssembler;
-        template <typename> friend class LinkBuffer;
+        template <typename, template <typename> class> friend class LinkBufferBase;
     public:
         DataLabel32()
         {
@@ -429,7 +431,7 @@ public:
     class DataLabelCompact {
         template<class TemplateAssemblerType>
         friend class AbstractMacroAssembler;
-        template <typename> friend class LinkBuffer;
+        template <typename, template <typename> class> friend class LinkBufferBase;
     public:
         DataLabelCompact()
         {
@@ -504,7 +506,7 @@ public:
         friend class AbstractMacroAssembler;
         friend class Call;
         friend struct DFG::OSRExit;
-        template <typename> friend class LinkBuffer;
+        template <typename, template <typename> class> friend class LinkBufferBase;
     public:
         Jump()
         {
@@ -646,7 +648,7 @@ public:
     // A JumpList is a set of Jump objects.
     // All jumps in the set will be linked to the same destination.
     class JumpList {
-        template <typename> friend class LinkBuffer;
+        template <typename, template <typename> class> friend class LinkBufferBase;
 
     public:
         typedef Vector<Jump, 2> JumpVector;
@@ -820,7 +822,8 @@ protected:
     static bool shouldBlindForSpecificArch(uint64_t) { return true; }
 #endif
 
-    template <typename> friend class LinkBuffer;
+    template <typename, template <typename> class> friend class LinkBufferBase;
+    template <typename> friend class BranchCompactingLinkBuffer;
     friend class RepatchBuffer;
 
     static void linkJump(void* code, Jump jump, CodeLocationLabel target)
diff --git a/src/3rdparty/masm/assembler/LinkBuffer.h b/src/3rdparty/masm/assembler/LinkBuffer.h
index 1de44439f8..4d8a129e18 100644
--- a/src/3rdparty/masm/assembler/LinkBuffer.h
+++ b/src/3rdparty/masm/assembler/LinkBuffer.h
@@ -44,6 +44,12 @@ namespace JSC {
 
 class JSGlobalData;
 
+template <typename T>
+struct DefaultExecutableOffsetCalculator {
+    template <typename Assembler>
+    static T applyOffset(Assembler *, T src) { return src; }
+};
+
 // LinkBuffer:
 //
 // This class assists in linking code generated by the macro assembler, once code generation
@@ -58,9 +64,9 @@ class JSGlobalData;
 //   * The address of a Label pointing into the code may be resolved.
 //   * The value referenced by a DataLabel may be set.
 //
-template <typename MacroAssembler>
-class LinkBuffer {
-    WTF_MAKE_NONCOPYABLE(LinkBuffer);
+template <typename MacroAssembler, template <typename T> class ExecutableOffsetCalculator>
+class LinkBufferBase {
+    WTF_MAKE_NONCOPYABLE(LinkBufferBase);
     typedef MacroAssemblerCodeRef CodeRef;
     typedef MacroAssemblerCodePtr CodePtr;
     typedef typename MacroAssembler::Label Label;
@@ -72,17 +78,10 @@ class LinkBuffer {
     typedef typename MacroAssembler::DataLabel32 DataLabel32;
     typedef typename MacroAssembler::DataLabelPtr DataLabelPtr;
     typedef typename MacroAssembler::ConvertibleLoadLabel ConvertibleLoadLabel;
-#if ENABLE(BRANCH_COMPACTION)
-    typedef typename MacroAssembler::LinkRecord LinkRecord;
-    typedef typename MacroAssembler::JumpLinkType JumpLinkType;
-#endif
 
 public:
-    LinkBuffer(JSGlobalData& globalData, MacroAssembler* masm, void* ownerUID, JITCompilationEffort effort = JITCompilationMustSucceed)
+    LinkBufferBase(JSGlobalData& globalData, MacroAssembler* masm, JITCompilationEffort effort = JITCompilationMustSucceed)
         : m_size(0)
-#if ENABLE(BRANCH_COMPACTION)
-        , m_initialSize(0)
-#endif
         , m_code(0)
         , m_assembler(masm)
         , m_globalData(&globalData)
@@ -91,10 +90,13 @@ public:
         , m_effort(effort)
 #endif
     {
-        linkCode(ownerUID, effort);
+#ifdef NDEBUG
+        UNUSED_PARAM(effort)
+#endif
+        // Simon: Moved this to the sub-classes linkCode(ownerUID, effort);
     }
 
-    ~LinkBuffer()
+    ~LinkBufferBase()
     {
         ASSERT(m_completed || (!m_executableMemory && m_effort == JITCompilationCanFail));
     }
@@ -227,12 +229,10 @@ public:
 private:
     template <typename T> T applyOffset(T src)
     {
-#if ENABLE(BRANCH_COMPACTION)
-        src.m_offset -= m_assembler->executableOffsetFor(src.m_offset);
-#endif
-        return src;
+        return ExecutableOffsetCalculator<T>::applyOffset(m_assembler, src);
     }
     
+protected:
     // Keep this private! - the underlying code should only be obtained externally via finalizeCode().
     void* code()
     {
@@ -253,12 +253,10 @@ private:
     
     RefPtr<ExecutableMemoryHandle> m_executableMemory;
     size_t m_size;
-#if ENABLE(BRANCH_COMPACTION)
-    size_t m_initialSize;
-#endif
     void* m_code;
     MacroAssembler* m_assembler;
     JSGlobalData* m_globalData;
+protected:
 #ifndef NDEBUG
     bool m_completed;
     JITCompilationEffort m_effort;
@@ -293,16 +291,16 @@ private:
     FINALIZE_CODE_IF((Options::showDisassembly() || Options::showDFGDisassembly()), linkBufferReference, dataLogFArgumentsForHeading)
 
 
-template <typename MacroAssembler>
-inline typename LinkBuffer<MacroAssembler>::CodeRef LinkBuffer<MacroAssembler>::finalizeCodeWithoutDisassembly()
+template <typename MacroAssembler, template <typename T> class ExecutableOffsetCalculator>
+inline typename LinkBufferBase<MacroAssembler, ExecutableOffsetCalculator>::CodeRef LinkBufferBase<MacroAssembler, ExecutableOffsetCalculator>::finalizeCodeWithoutDisassembly()
 {
     performFinalization();
 
     return CodeRef(m_executableMemory);
 }
 
-template <typename MacroAssembler>
-inline typename LinkBuffer<MacroAssembler>::CodeRef LinkBuffer<MacroAssembler>::finalizeCodeWithDisassembly(const char* format, ...)
+template <typename MacroAssembler, template <typename T> class ExecutableOffsetCalculator>
+inline typename LinkBufferBase<MacroAssembler, ExecutableOffsetCalculator>::CodeRef LinkBufferBase<MacroAssembler, ExecutableOffsetCalculator>::finalizeCodeWithDisassembly(const char* format, ...)
 {
     ASSERT(Options::showDisassembly() || Options::showDFGDisassembly());
 
@@ -327,18 +325,109 @@ inline typename LinkBuffer<MacroAssembler>::CodeRef LinkBuffer<MacroAssembler>::
     return result;
 }
 
-template <typename MacroAssembler>
-inline void LinkBuffer<MacroAssembler>::linkCode(void* ownerUID, JITCompilationEffort effort)
+template <typename MacroAssembler, template <typename T> class ExecutableOffsetCalculator>
+inline void LinkBufferBase<MacroAssembler, ExecutableOffsetCalculator>::linkCode(void* ownerUID, JITCompilationEffort effort)
 {
+    UNUSED_PARAM(ownerUID)
+    UNUSED_PARAM(effort)
     ASSERT(!m_code);
-#if !ENABLE(BRANCH_COMPACTION)
     m_executableMemory = m_assembler->m_assembler.executableCopy(*m_globalData, ownerUID, effort);
     if (!m_executableMemory)
         return;
     m_code = m_executableMemory->start();
     m_size = m_assembler->m_assembler.codeSize();
     ASSERT(m_code);
-#else
+}
+
+template <typename MacroAssembler, template <typename T> class ExecutableOffsetCalculator>
+inline void LinkBufferBase<MacroAssembler, ExecutableOffsetCalculator>::performFinalization()
+{
+    // NOTE: This function is specialized in LinkBuffer<MacroAssemblerARMv7>
+#ifndef NDEBUG
+    ASSERT(!m_completed);
+    ASSERT(isValid());
+    m_completed = true;
+#endif
+
+    ASSERT(m_size <= INT_MAX);
+    ExecutableAllocator::makeExecutable(code(), static_cast<int>(m_size));
+    MacroAssembler::cacheFlush(code(), m_size);
+}
+
+template <typename MacroAssembler>
+class LinkBuffer : public LinkBufferBase<MacroAssembler, DefaultExecutableOffsetCalculator>
+{
+public:
+    LinkBuffer(JSGlobalData& globalData, MacroAssembler* masm, void* ownerUID, JITCompilationEffort effort = JITCompilationMustSucceed)
+        : LinkBufferBase<MacroAssembler, DefaultExecutableOffsetCalculator>(globalData, masm, effort)
+    {
+        this->linkCode(ownerUID, effort);
+    }
+};
+
+#if CPU(ARM_THUMB2) || CPU(ARM64)
+
+template <typename T>
+struct BranchCompactingExecutableOffsetCalculator {
+    template <typename Assembler>
+    static T applyOffset(Assembler *as, T src) {
+        src.m_offset -= as->executableOffsetFor(src.m_offset);
+        return src;
+    }
+};
+
+template <typename MacroAssembler>
+class BranchCompactingLinkBuffer : public LinkBufferBase<MacroAssembler, BranchCompactingExecutableOffsetCalculator>
+{
+public:
+    BranchCompactingLinkBuffer(JSGlobalData& globalData, MacroAssembler* masm, void* ownerUID, JITCompilationEffort effort = JITCompilationMustSucceed)
+        : LinkBufferBase<MacroAssembler, BranchCompactingExecutableOffsetCalculator>(globalData, masm, effort)
+    {
+        linkCode(ownerUID, effort);
+    }
+
+    inline void performFinalization();
+
+    inline void linkCode(void* ownerUID, JITCompilationEffort);
+
+private:
+    using Base = LinkBufferBase<MacroAssembler, BranchCompactingExecutableOffsetCalculator>;
+#ifndef NDEBUG
+    using Base::m_completed;
+#endif
+    using Base::isValid;
+    using Base::code;
+    using Base::m_code;
+    using Base::m_size;
+    using Base::m_assembler;
+    using Base::m_executableMemory;
+    using Base::m_globalData;
+
+    using LinkRecord = typename MacroAssembler::LinkRecord;
+    using JumpLinkType = typename MacroAssembler::JumpLinkType;
+
+    size_t m_initialSize = 0;
+};
+
+template <typename MacroAssembler>
+inline void BranchCompactingLinkBuffer<MacroAssembler>::performFinalization()
+{
+#ifndef NDEBUG
+    ASSERT(!m_completed);
+    ASSERT(isValid());
+    this->m_completed = true;
+#endif
+
+    ExecutableAllocator::makeExecutable(code(), m_initialSize);
+    MacroAssembler::cacheFlush(code(), m_size);
+}
+
+template <typename MacroAssembler>
+inline void BranchCompactingLinkBuffer<MacroAssembler>::linkCode(void* ownerUID, JITCompilationEffort effort)
+{
+    UNUSED_PARAM(ownerUID)
+    UNUSED_PARAM(effort)
+    ASSERT(!m_code);
     m_initialSize = m_assembler->m_assembler.codeSize();
     m_executableMemory = m_globalData->executableAllocator.allocate(*m_globalData, m_initialSize, ownerUID, effort);
     if (!m_executableMemory)
@@ -403,33 +492,32 @@ inline void LinkBuffer<MacroAssembler>::linkCode(void* ownerUID, JITCompilationE
     jumpsToLink.clear();
     m_size = writePtr + m_initialSize - readPtr;
     m_executableMemory->shrink(m_size);
+}
 
-#if DUMP_LINK_STATISTICS
-    dumpLinkStatistics(m_code, m_initialSize, m_size);
-#endif
-#if DUMP_CODE
-    dumpCode(m_code, m_size);
-#endif
+#if CPU(ARM_THUMB2)
+template <>
+class LinkBuffer<JSC::MacroAssembler<MacroAssemblerARMv7>> : public BranchCompactingLinkBuffer<JSC::MacroAssembler<MacroAssemblerARMv7>>
+{
+public:
+    LinkBuffer(JSGlobalData& globalData, JSC::MacroAssembler<MacroAssemblerARMv7>* masm, void* ownerUID, JITCompilationEffort effort = JITCompilationMustSucceed)
+        : BranchCompactingLinkBuffer<JSC::MacroAssembler<MacroAssemblerARMv7>>(globalData, masm, ownerUID, effort)
+    {}
+};
 #endif
-}
 
-template <typename MacroAssembler>
-inline void LinkBuffer<MacroAssembler>::performFinalization()
+#if CPU(ARM64)
+template <>
+class LinkBuffer<JSC::MacroAssembler<MacroAssemblerARM64>> : public BranchCompactingLinkBuffer<JSC::MacroAssembler<MacroAssemblerARM64>>
 {
-#ifndef NDEBUG
-    ASSERT(!m_completed);
-    ASSERT(isValid());
-    m_completed = true;
+public:
+    LinkBuffer(JSGlobalData& globalData, JSC::MacroAssembler<MacroAssemblerARM64>* masm, void* ownerUID, JITCompilationEffort effort = JITCompilationMustSucceed)
+        : BranchCompactingLinkBuffer<JSC::MacroAssembler<JSC::MacroAssemblerARM64>>(globalData, masm, ownerUID, effort)
+    {}
+};
 #endif
 
-#if ENABLE(BRANCH_COMPACTION)
-    ExecutableAllocator::makeExecutable(code(), m_initialSize);
-#else
-    ASSERT(m_size <= INT_MAX);
-    ExecutableAllocator::makeExecutable(code(), static_cast<int>(m_size));
 #endif
-    MacroAssembler::cacheFlush(code(), m_size);
-}
+
 } // namespace JSC
 
 #endif // ENABLE(ASSEMBLER)
diff --git a/src/3rdparty/masm/assembler/MacroAssemblerARM.h b/src/3rdparty/masm/assembler/MacroAssemblerARM.h
index 87c236df3a..268fe5fe73 100644
--- a/src/3rdparty/masm/assembler/MacroAssemblerARM.h
+++ b/src/3rdparty/masm/assembler/MacroAssemblerARM.h
@@ -1349,7 +1349,7 @@ protected:
     }
 
 private:
-    template <typename> friend class LinkBuffer;
+    template <typename, template <typename> class> friend class LinkBufferBase;
     friend class RepatchBuffer;
 
     void internalCompare32(RegisterID left, TrustedImm32 right)
diff --git a/src/3rdparty/masm/assembler/MacroAssemblerARM64.h b/src/3rdparty/masm/assembler/MacroAssemblerARM64.h
index 37c952b9f3..3e425a0246 100644
--- a/src/3rdparty/masm/assembler/MacroAssemblerARM64.h
+++ b/src/3rdparty/masm/assembler/MacroAssemblerARM64.h
@@ -3353,7 +3353,7 @@ private:
         return makeBranch(cond);
     }
 
-    template <typename> friend class LinkBuffer;
+    template <typename, template <typename> class> friend class LinkBufferBase;
     void recordLinkOffsets(int32_t regionStart, int32_t regionEnd, int32_t offset) {return m_assembler.recordLinkOffsets(regionStart, regionEnd, offset); }
     int executableOffsetFor(int location) { return m_assembler.executableOffsetFor(location); }
 
diff --git a/src/3rdparty/masm/assembler/MacroAssemblerARMv7.h b/src/3rdparty/masm/assembler/MacroAssemblerARMv7.h
index 9f5a089a75..3f6352c1db 100644
--- a/src/3rdparty/masm/assembler/MacroAssemblerARMv7.h
+++ b/src/3rdparty/masm/assembler/MacroAssemblerARMv7.h
@@ -1930,7 +1930,7 @@ protected:
     }
     
 private:
-    template <typename> friend class LinkBuffer;
+    template <typename, template <typename> class> friend class LinkBufferBase;
     friend class RepatchBuffer;
 
     static void linkCall(void* code, Call call, FunctionPtr function)
diff --git a/src/3rdparty/masm/assembler/MacroAssemblerMIPS.h b/src/3rdparty/masm/assembler/MacroAssemblerMIPS.h
index 3664321cff..68584527fc 100644
--- a/src/3rdparty/masm/assembler/MacroAssemblerMIPS.h
+++ b/src/3rdparty/masm/assembler/MacroAssemblerMIPS.h
@@ -2802,7 +2802,7 @@ private:
     // Otherwise, we can emit any number of instructions.
     bool m_fixedWidth;
 
-    template <typename> friend class LinkBuffer;
+    template <typename, template <typename> class> friend class LinkBufferBase;
     friend class RepatchBuffer;
 
     static void linkCall(void* code, Call call, FunctionPtr function)
diff --git a/src/3rdparty/masm/assembler/MacroAssemblerSH4.h b/src/3rdparty/masm/assembler/MacroAssemblerSH4.h
index 336d96834f..1e5a3113bb 100644
--- a/src/3rdparty/masm/assembler/MacroAssemblerSH4.h
+++ b/src/3rdparty/masm/assembler/MacroAssemblerSH4.h
@@ -2278,7 +2278,7 @@ protected:
         return static_cast<SH4Assembler::Condition>(cond);
     }
 private:
-    template <typename>  friend class LinkBuffer;
+    template <typename, template <typename> class> friend class LinkBufferBase;
     friend class RepatchBuffer;
 
     static void linkCall(void*, Call, FunctionPtr);
diff --git a/src/3rdparty/masm/assembler/MacroAssemblerX86.h b/src/3rdparty/masm/assembler/MacroAssemblerX86.h
index 5ae3e5efd9..c42100bbcb 100644
--- a/src/3rdparty/masm/assembler/MacroAssemblerX86.h
+++ b/src/3rdparty/masm/assembler/MacroAssemblerX86.h
@@ -306,7 +306,7 @@ public:
     }
 
 private:
-    template <typename>  friend class LinkBuffer;
+    template <typename, template <typename> class> friend class LinkBufferBase;
     friend class RepatchBuffer;
 
     static void linkCall(void* code, Call call, FunctionPtr function)
diff --git a/src/3rdparty/masm/assembler/MacroAssemblerX86_64.h b/src/3rdparty/masm/assembler/MacroAssemblerX86_64.h
index 52c1f89cad..47ca952a05 100644
--- a/src/3rdparty/masm/assembler/MacroAssemblerX86_64.h
+++ b/src/3rdparty/masm/assembler/MacroAssemblerX86_64.h
@@ -634,7 +634,7 @@ public:
     }
 
 private:
-    template <typename> friend class LinkBuffer;
+    template <typename, template <typename> class> friend class LinkBufferBase;
     friend class RepatchBuffer;
 
     static void linkCall(void* code, Call call, FunctionPtr function)