Include the ARMv7 assembler in the qmldevtools bootstrap build

Even when the C++ target is not ARMv7 we want to include it in order to
be able to generate QML cache files with code ahead of time.

This requires a few changes:

* The Jump classes need to move from the AbstractMacroAssembler
  super-class into the concrete assembler sub-class, in order to
  use it in specializations.
* Some of the template specializations in LinkBuffer for example or
  for platform dependent operations need to be pre-processor enabled
  when bootstrapping
* The generic loadPtr/addPtr etc. functions need to move to the concrete
  assemblers to be able to call the correct 32-bit or 64-bit variations.
* We need to force what looks like a loss of precision to the compiler
  in the 32-bit ARMv7 linking code when linking jumps.

Finally then we can explicitly instantiate at least QV4::JIT::Assembler
for ARMv7 when bootstrapping. Currently only on x86-64 hosts, but that
is a temporary limitation.

Change-Id: I501db2360e1fded48f17f17d9e87252d47f8537e
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 17 insertions, 3 deletions

diff --git a/src/3rdparty/masm/assembler/AbstractMacroAssembler.h b/src/3rdparty/masm/assembler/AbstractMacroAssembler.h
index a9035efed7..4f27e85c98 100644
--- a/src/3rdparty/masm/assembler/AbstractMacroAssembler.h
+++ b/src/3rdparty/masm/assembler/AbstractMacroAssembler.h
@@ -66,7 +66,9 @@ public:
     typedef MacroAssemblerCodePtr CodePtr;
     typedef MacroAssemblerCodeRef CodeRef;
 
+#if !CPU(ARM_THUMB2) && !defined(V4_BOOTSTRAP)
     class Jump;
+#endif
 
     typedef typename AssemblerType::RegisterID RegisterID;
     typedef typename AssemblerType::FPRegisterID FPRegisterID;
@@ -342,6 +344,8 @@ public:
         }
         
         bool isSet() const { return m_label.isSet(); }
+
+        const AssemblerLabel &label() const { return m_label; }
     private:
         AssemblerLabel m_label;
     };
@@ -451,6 +455,11 @@ public:
         AssemblerLabel m_label;
     };
 
+#if CPU(ARM_THUMB2) || defined(V4_BOOTSTRAP)
+    using Jump = typename AssemblerType::template Jump<Label>;
+    friend Jump;
+#endif
+
     // Call:
     //
     // A Call object is a reference to a call instruction that has been planted
@@ -501,6 +510,7 @@ public:
     // into the code buffer - it is typically used to link the jump, setting the
     // relative offset such that when executed it will jump to the desired
     // destination.
+#if !CPU(ARM_THUMB2) && !defined(V4_BOOTSTRAP)
     class Jump {
         template<class TemplateAssemblerType>
         friend class AbstractMacroAssembler;
@@ -512,7 +522,7 @@ public:
         {
         }
         
-#if CPU(ARM_THUMB2)
+#if CPU(ARM_THUMB2) || defined(V4_BOOTSTRAP)
         // Fixme: this information should be stored in the instruction stream, not in the Jump object.
         Jump(AssemblerLabel jmp, ARMv7Assembler::JumpType type = ARMv7Assembler::JumpNoCondition, ARMv7Assembler::Condition condition = ARMv7Assembler::ConditionInvalid)
             : m_label(jmp)
@@ -613,10 +623,11 @@ public:
 
     private:
         AssemblerLabel m_label;
-#if CPU(ARM_THUMB2)
+#if CPU(ARM_THUMB2) || defined(V4_BOOTSTRAP)
         ARMv7Assembler::JumpType m_type;
         ARMv7Assembler::Condition m_condition;
-#elif CPU(ARM64)
+#endif
+#if CPU(ARM64)
         ARM64Assembler::JumpType m_type;
         ARM64Assembler::Condition m_condition;
         bool m_is64Bit;
@@ -627,6 +638,7 @@ public:
         SH4Assembler::JumpType m_type;
 #endif
     };
+#endif
 
     struct PatchableJump {
         PatchableJump()
@@ -871,10 +883,12 @@ protected:
         AssemblerType::repatchPointer(dataLabelPtr.dataLocation(), value);
     }
     
+#if !defined(V4_BOOTSTRAP)
     static void* readPointer(CodeLocationDataLabelPtr dataLabelPtr)
     {
         return AssemblerType::readPointer(dataLabelPtr.dataLocation());
     }
+#endif
     
     static void replaceWithLoad(CodeLocationConvertibleLoad label)
     {