Issue #3049 - Enable loongarch64 wasm runtime and Ion patching

dom/workers/RuntimeService.cpp

@@ -295,9 +295,8 @@ LoadContextOptions(const char* aPrefName, void* /* aClosure */)
   bool useIon = GetWorkerPref<bool>(NS_LITERAL_CSTRING("ion"));
 
 #if defined(JS_CODEGEN_LOONGARCH64)
-  // asm.js and wasm are still disabled on loongarch64 workers.
+  // asm.js is still disabled on loongarch64 workers.
   useAsmJS = false;
-  useWasm = false;
 #endif
 
   bool useNativeRegExp = GetWorkerPref<bool>(NS_LITERAL_CSTRING("native_regexp"));

js/src/jit/MacroAssembler.cpp

@@ -1875,7 +1875,8 @@ MacroAssembler::outOfLineTruncateSlow(FloatRegister src, Register dest, bool wid
                                       bool compilingWasm)
 {
 #if defined(JS_CODEGEN_ARM) || defined(JS_CODEGEN_ARM64) || \
-    defined(JS_CODEGEN_MIPS32) || defined(JS_CODEGEN_MIPS64)
+    defined(JS_CODEGEN_MIPS32) || defined(JS_CODEGEN_MIPS64) || \
+    defined(JS_CODEGEN_LOONGARCH64)
     if (widenFloatToDouble) {
         convertFloat32ToDouble(src, ScratchDoubleReg);
         src = ScratchDoubleReg;
@@ -1905,7 +1906,8 @@ MacroAssembler::outOfLineTruncateSlow(FloatRegister src, Register dest, bool wid
     storeCallInt32Result(dest);
 
 #if defined(JS_CODEGEN_ARM) || defined(JS_CODEGEN_ARM64) || \
-    defined(JS_CODEGEN_MIPS32) || defined(JS_CODEGEN_MIPS64)
+    defined(JS_CODEGEN_MIPS32) || defined(JS_CODEGEN_MIPS64) || \
+    defined(JS_CODEGEN_LOONGARCH64)
     // Nothing
 #elif defined(JS_CODEGEN_X86) || defined(JS_CODEGEN_X64)
     if (widenFloatToDouble)

js/src/jit/loongarch64/Assembler-loongarch64.cpp

@@ -20,10 +20,22 @@ using namespace js::jit;
 
 void js::jit::PatchJump(CodeLocationJump& jump_, CodeLocationLabel label,
                         ReprotectCode reprotect) {
-  (void)jump_;
-  (void)label;
-  (void)reprotect;
-  MOZ_CRASH("Ion patching is not supported on loongarch64");
+  Instruction* inst = reinterpret_cast<Instruction*>(jump_.raw());
+
+  // jumpWithPatch() reserves four instructions:
+  //   beq zero, zero, 0
+  //   INVALID_OFFSET
+  //   nop
+  //   nop
+  // Patch that block into the long-jump form used elsewhere in the backend:
+  //   load64 scratch, target
+  //   jirl zero, scratch, 0
+  MaybeAutoWritableJitCode awjc(inst, 4 * sizeof(uint32_t), reprotect);
+  Assembler::WriteLoad64Instructions(inst, ScratchRegister,
+                                     uintptr_t(label.raw()));
+  inst[3] = InstImm(op_jirl, BOffImm16(0), ScratchRegister, zero);
+
+  AutoFlushICache::flush(uintptr_t(inst), 4 * sizeof(uint32_t));
 }
 
 // Note this is used for inter-wasm calls and may pass arguments and results

js/src/jit/loongarch64/Assembler-loongarch64.h

@@ -209,6 +209,12 @@ static constexpr Register WasmTableCallScratchReg1 = ABINonArgReg1;
 static constexpr Register WasmTableCallScratchReg = WasmTableCallScratchReg0;
 static constexpr Register WasmTableCallSigReg = ABINonArgReg2;
 static constexpr Register WasmTableCallIndexReg = ABINonArgReg3;
+static constexpr Register WasmIonExitRegCallee = t0;
+static constexpr Register WasmIonExitRegE0 = a0;
+static constexpr Register WasmIonExitRegE1 = a1;
+static constexpr Register WasmIonExitRegD0 = a0;
+static constexpr Register WasmIonExitRegD1 = a1;
+static constexpr Register WasmIonExitRegD2 = t0;
 
 // Register used as a scratch along the return path in the fast js -> wasm stub
 // code. This must not overlap ReturnReg, JSReturnOperand, or InstanceReg.

js/src/wasm/WasmJS.cpp

@@ -66,7 +66,7 @@ wasm::HasCompilerSupport(ExclusiveContext* cx)
         return false;
 #endif
 
-#if defined(JS_CODEGEN_NONE) || defined(JS_CODEGEN_ARM64) || defined(JS_CODEGEN_LOONGARCH64)
+#if defined(JS_CODEGEN_NONE) || defined(JS_CODEGEN_ARM64)
     return false;
 #else
     return true;

js/src/wasm/WasmSignalHandlers.cpp

@@ -1363,13 +1363,6 @@ ProcessHasSignalHandlers()
 # endif
 #endif
 
-#if defined(JS_CODEGEN_LOONGARCH64)
-    // The loongarch64 port is baseline-only for now: no wasm compiler support
-    // and no Ion interrupt machinery that depends on these process-wide
-    // signal handlers. Keeping them installed risks misrouting ordinary faults.
-    return false;
-#endif
-
     // The interrupt handler allows the main thread to be paused from another
     // thread (see InterruptRunningJitCode).
 #if defined(XP_WIN)

js/src/wasm/WasmStubs.cpp

@@ -588,10 +588,6 @@ static const unsigned SavedTlsReg = sizeof(void*);
 ProfilingOffsets
 wasm::GenerateImportJitExit(MacroAssembler& masm, const FuncImport& fi, Label* throwLabel)
 {
-#if defined(JS_CODEGEN_LOONGARCH64)
-    MOZ_CRASH("wasm import JIT exits are unsupported on loongarch64");
-    return ProfilingOffsets();
-#else
     masm.setFramePushed(0);
 
     // JIT calls use the following stack layout (sp grows to the left):
@@ -814,7 +810,6 @@ wasm::GenerateImportJitExit(MacroAssembler& masm, const FuncImport& fi, Label* t
 
     offsets.end = masm.currentOffset();
     return offsets;
-#endif
 }
 
 // Generate a stub that calls into ReportTrap with the right trap reason.
@@ -1056,7 +1051,38 @@ wasm::GenerateInterruptExit(MacroAssembler& masm, Label* throwLabel)
     masm.ret();
 #elif defined(JS_CODEGEN_ARM64)
     MOZ_CRASH();
-#elif defined (JS_CODEGEN_NONE) || defined(JS_CODEGEN_LOONGARCH64)
+#elif defined(JS_CODEGEN_LOONGARCH64)
+    // Reserve space to store the resumePC. We restore all machine state from
+    // the saved register image and use the reserved `rx` register as the final
+    // jump scratch to resume execution.
+    masm.subFromStackPtr(Imm32(sizeof(intptr_t)));
+    masm.setFramePushed(0);
+    static_assert(!SupportsSimd, "high lanes of SIMD registers need to be saved too.");
+    masm.PushRegsInMask(AllRegsExceptSP);
+
+    // Save the unaligned stack pointer in a non-volatile register, then align
+    // for the C++ call into HandleExecutionInterrupt.
+    masm.moveStackPtrTo(s0);
+    masm.andToStackPtr(Imm32(~(ABIStackAlignment - 1)));
+
+    // Store resumePC into the reserved space above the saved register block.
+    masm.loadWasmActivationFromSymbolicAddress(IntArgReg0);
+    masm.loadPtr(Address(IntArgReg0, WasmActivation::offsetOfResumePC()), IntArgReg1);
+    masm.storePtr(IntArgReg1, Address(s0, masm.framePushed()));
+
+    masm.assertStackAlignment(ABIStackAlignment);
+    masm.call(SymbolicAddress::HandleExecutionInterrupt);
+
+    masm.branchIfFalseBool(ReturnReg, throwLabel);
+
+    // Restore the interrupted machine state before resuming execution.
+    masm.moveToStackPtr(s0);
+    masm.PopRegsInMask(AllRegsExceptSP);
+
+    masm.loadPtr(Address(StackPointer, 0), rx);
+    masm.addToStackPtr(Imm32(sizeof(intptr_t)));
+    masm.jump(rx);
+#elif defined (JS_CODEGEN_NONE)
     MOZ_CRASH();
 #else
 # error "Unknown architecture!"

js/xpconnect/src/XPCJSContext.cpp

@@ -1421,10 +1421,8 @@ ReloadPrefsCallback(const char* pref, void* data)
     bool useNativeRegExp = Preferences::GetBool(JS_OPTIONS_DOT_STR "native_regexp") && !safeMode;
 
 #if defined(JS_CODEGEN_LOONGARCH64)
-    // asm.js, wasm, and native regexp JIT are still disabled on loongarch64.
+    // asm.js and native regexp JIT are still disabled on loongarch64.
     useAsmJS = false;
-    useWasm = false;
-    useWasmBaseline = false;
     useNativeRegExp = false;
 #endif
 

modules/libpref/init/all.js

@@ -1266,7 +1266,7 @@ pref("javascript.options.baselinejit",      true);
 #if defined(JS_CODEGEN_LOONGARCH64)
 pref("javascript.options.ion",              true);
 pref("javascript.options.asmjs",            false);
-pref("javascript.options.wasm",             false);
+pref("javascript.options.wasm",             true);
 #else
 pref("javascript.options.ion",              true);
 // JIT warm-up thresholds (-1 keeps engine defaults).
@@ -1282,7 +1282,7 @@ pref("javascript.options.ion.inlining",     true);
 // only enable it by default for 64bit builds
 #ifdef HAVE_64BIT_BUILD
 # if defined(JS_CODEGEN_LOONGARCH64)
-pref("javascript.options.wasm_baselinejit", false);
+pref("javascript.options.wasm_baselinejit", true);
 # else
 pref("javascript.options.wasm_baselinejit", true);
 # endif