Bug 1271968 - IonMonkey: MIPS: Replace long jumps by mixed jumps.

Tag: #1542

1 files changed, 25 insertions, 76 deletions

diff --git a/js/src/jit/mips32/Assembler-mips32.cpp b/js/src/jit/mips32/Assembler-mips32.cpp
index 1b86e9d32..461f8d813 100644
--- a/js/src/jit/mips32/Assembler-mips32.cpp
+++ b/js/src/jit/mips32/Assembler-mips32.cpp
@@ -120,8 +120,11 @@ js::jit::SA(FloatRegister r)
 void
 jit::PatchJump(CodeLocationJump& jump_, CodeLocationLabel label, ReprotectCode reprotect)
 {
-    Instruction* inst1 = (Instruction*)jump_.raw();
-    Instruction* inst2 = inst1->next();
+    Instruction* inst1;
+    Instruction* inst2;
+
+    inst1 = AssemblerMIPSShared::GetInstructionImmediateFromJump((Instruction*)jump_.raw());
+    inst2 = inst1->next();
 
     MaybeAutoWritableJitCode awjc(inst1, 8, reprotect);
     AssemblerMIPSShared::UpdateLuiOriValue(inst1, inst2, (uint32_t)label.raw());
@@ -157,23 +160,6 @@ jit::PatchBackedge(CodeLocationJump& jump, CodeLocationLabel label,
     }
 }
 
-void
-Assembler::executableCopy(uint8_t* buffer)
-{
-    MOZ_ASSERT(isFinished);
-    m_buffer.executableCopy(buffer);
-
-    // Patch all long jumps during code copy.
-    for (size_t i = 0; i < longJumps_.length(); i++) {
-        Instruction* inst1 = (Instruction*) ((uint32_t)buffer + longJumps_[i]);
-
-        uint32_t value = Assembler::ExtractLuiOriValue(inst1, inst1->next());
-        AssemblerMIPSShared::UpdateLuiOriValue(inst1, inst1->next(), (uint32_t)buffer + value);
-    }
-
-    AutoFlushICache::setRange(uintptr_t(buffer), m_buffer.size());
-}
-
 uintptr_t
 Assembler::GetPointer(uint8_t* instPtr)
 {
@@ -314,8 +300,12 @@ void
 Assembler::bind(InstImm* inst, uintptr_t branch, uintptr_t target)
 {
     int32_t offset = target - branch;
-    InstImm inst_bgezal = InstImm(op_regimm, zero, rt_bgezal, BOffImm16(0));
-    InstImm inst_beq = InstImm(op_beq, zero, zero, BOffImm16(0));
+
+    // Generate the patchable mixed jump for call.
+    if (inst->extractOpcode() == ((uint32_t)op_jal >> OpcodeShift)) {
+        addMixedJump(BufferOffset(branch), ImmPtr((void*)target));
+        return;
+    }
 
     // If encoded offset is 4, then the jump must be short
     if (BOffImm16(inst[0]).decode() == 4) {
@@ -325,46 +315,13 @@ Assembler::bind(InstImm* inst, uintptr_t branch, uintptr_t target)
         return;
     }
 
-    // Generate the long jump for calls because return address has to be the
-    // address after the reserved block.
-    if (inst[0].encode() == inst_bgezal.encode()) {
-        addLongJump(BufferOffset(branch));
-        Assembler::WriteLuiOriInstructions(inst, &inst[1], ScratchRegister, target);
-        inst[2] = InstReg(op_special, ScratchRegister, zero, ra, ff_jalr).encode();
-        // There is 1 nop after this.
-        return;
-    }
-
     if (BOffImm16::IsInRange(offset)) {
-        bool conditional = (inst[0].encode() != inst_bgezal.encode() &&
-                            inst[0].encode() != inst_beq.encode());
-
         inst[0].setBOffImm16(BOffImm16(offset));
         inst[1].makeNop();
-
-        // Skip the trailing nops in conditional branches.
-        if (conditional) {
-            inst[2] = InstImm(op_regimm, zero, rt_bgez, BOffImm16(3 * sizeof(void*))).encode();
-            // There are 2 nops after this
-        }
         return;
     }
 
-    if (inst[0].encode() == inst_beq.encode()) {
-        // Handle long unconditional jump.
-        addLongJump(BufferOffset(branch));
-        Assembler::WriteLuiOriInstructions(inst, &inst[1], ScratchRegister, target);
-        inst[2] = InstReg(op_special, ScratchRegister, zero, zero, ff_jr).encode();
-        // There is 1 nop after this.
-    } else {
-        // Handle long conditional jump.
-        inst[0] = invertBranch(inst[0], BOffImm16(5 * sizeof(void*)));
-        // No need for a "nop" here because we can clobber scratch.
-        addLongJump(BufferOffset(branch + sizeof(void*)));
-        Assembler::WriteLuiOriInstructions(&inst[1], &inst[2], ScratchRegister, target);
-        inst[3] = InstReg(op_special, ScratchRegister, zero, zero, ff_jr).encode();
-        // There is 1 nop after this.
-    }
+    addMixedJump(BufferOffset(branch), ImmPtr((const void*)target));
 }
 
 void
@@ -379,19 +336,16 @@ Assembler::bind(RepatchLabel* label)
         InstImm inst_beq = InstImm(op_beq, zero, zero, BOffImm16(0));
         uint32_t offset = dest.getOffset() - label->offset();
 
-        // If first instruction is lui, then this is a long jump.
+        // If first instruction is j, then this is a mixed jump.
         // If second instruction is lui, then this is a loop backedge.
-        if (inst[0].extractOpcode() == (uint32_t(op_lui) >> OpcodeShift)) {
-            // For unconditional long branches generated by ma_liPatchable,
-            // such as under:
-            //     jumpWithpatch
-            AssemblerMIPSShared::UpdateLuiOriValue(inst, inst->next(), dest.getOffset());
+        if (inst[0].extractOpcode() == (uint32_t(op_j) >> OpcodeShift)) {
+            // For unconditional long branches generated by jumpWithPatch
+            addMixedJump(b, ImmPtr((void*)dest.getOffset()), MixedJumpPatch::PATCHABLE);
         } else if (inst[1].extractOpcode() == (uint32_t(op_lui) >> OpcodeShift) ||
                    BOffImm16::IsInRange(offset))
         {
             // Handle code produced by:
             //     backedgeJump
-            //     branchWithCode
             MOZ_ASSERT(BOffImm16::IsInRange(offset));
             MOZ_ASSERT(inst[0].extractOpcode() == (uint32_t(op_beq) >> OpcodeShift) ||
                        inst[0].extractOpcode() == (uint32_t(op_bne) >> OpcodeShift) ||
@@ -399,30 +353,25 @@ Assembler::bind(RepatchLabel* label)
                        inst[0].extractOpcode() == (uint32_t(op_bgtz) >> OpcodeShift));
             inst[0].setBOffImm16(BOffImm16(offset));
         } else if (inst[0].encode() == inst_beq.encode()) {
-            // Handle open long unconditional jumps created by
+            // Handle open mixed unconditional jumps created by
             // MacroAssemblerMIPSShared::ma_b(..., wasm::Trap, ...).
-            // We need to add it to long jumps array here.
+            // We need to add it to mixed jumps array here.
             // See MacroAssemblerMIPS::branchWithCode().
             MOZ_ASSERT(inst[1].encode() == NopInst);
-            MOZ_ASSERT(inst[2].encode() == NopInst);
-            MOZ_ASSERT(inst[3].encode() == NopInst);
-            addLongJump(BufferOffset(label->offset()));
-            Assembler::WriteLuiOriInstructions(inst, &inst[1], ScratchRegister, dest.getOffset());
-            inst[2] = InstReg(op_special, ScratchRegister, zero, zero, ff_jr).encode();
+            addMixedJump(b, ImmPtr((void*)dest.getOffset()), MixedJumpPatch::PATCHABLE);
+            inst[0] = InstJump(op_j, JOffImm26(0)).encode();
         } else {
-            // Handle open long conditional jumps created by
+            // Handle open mixed conditional jumps created by
             // MacroAssemblerMIPSShared::ma_b(..., wasm::Trap, ...).
-            inst[0] = invertBranch(inst[0], BOffImm16(5 * sizeof(void*)));
+            inst[0] = invertBranch(inst[0], BOffImm16(4 * sizeof(void*)));
             // No need for a "nop" here because we can clobber scratch.
-            // We need to add it to long jumps array here.
+            // We need to add it to mixed jumps array here.
             // See MacroAssemblerMIPS::branchWithCode().
             MOZ_ASSERT(inst[1].encode() == NopInst);
             MOZ_ASSERT(inst[2].encode() == NopInst);
             MOZ_ASSERT(inst[3].encode() == NopInst);
-            MOZ_ASSERT(inst[4].encode() == NopInst);
-            addLongJump(BufferOffset(label->offset() + sizeof(void*)));
-            Assembler::WriteLuiOriInstructions(&inst[1], &inst[2], ScratchRegister, dest.getOffset());
-            inst[3] = InstReg(op_special, ScratchRegister, zero, zero, ff_jr).encode();
+            addMixedJump(b, ImmPtr((void*)dest.getOffset()), MixedJumpPatch::PATCHABLE);
+            inst[2] = InstJump(op_j, JOffImm26(0)).encode();
         }
     }
     label->bind(dest.getOffset());