Bug 1277973 - Baldr: replace WasmTlsReg load with SymbolicAddress load in prologue/epilogue (r=bbouvier)

MozReview-Commit-ID: 7lCcT7ymRkZ

--HG--
extra : rebase_source : f1cf824becfbff48c4414f9b1f08d0793a818a50

js/src/asmjs/WasmFrameIterator.cpp

@@ -218,19 +218,19 @@ FrameIterator::lineOrBytecode() const
 static const unsigned PushedRetAddr = 0;
 static const unsigned PostStorePrePopFP = 0;
 # endif
-static const unsigned PushedFP = 16;
-static const unsigned StoredFP = 23;
+static const unsigned PushedFP = 23;
+static const unsigned StoredFP = 30;
 #elif defined(JS_CODEGEN_X86)
 # if defined(DEBUG)
 static const unsigned PushedRetAddr = 0;
 static const unsigned PostStorePrePopFP = 0;
 # endif
-static const unsigned PushedFP = 11;
-static const unsigned StoredFP = 14;
+static const unsigned PushedFP = 14;
+static const unsigned StoredFP = 17;
 #elif defined(JS_CODEGEN_ARM)
 static const unsigned PushedRetAddr = 4;
-static const unsigned PushedFP = 20;
-static const unsigned StoredFP = 24;
+static const unsigned PushedFP = 24;
+static const unsigned StoredFP = 28;
 static const unsigned PostStorePrePopFP = 4;
 #elif defined(JS_CODEGEN_ARM64)
 static const unsigned PushedRetAddr = 0;
@@ -239,8 +239,8 @@ static const unsigned StoredFP = 0;
 static const unsigned PostStorePrePopFP = 0;
 #elif defined(JS_CODEGEN_MIPS32) || defined(JS_CODEGEN_MIPS64)
 static const unsigned PushedRetAddr = 8;
-static const unsigned PushedFP = 28;
-static const unsigned StoredFP = 32;
+static const unsigned PushedFP = 32;
+static const unsigned StoredFP = 36;
 static const unsigned PostStorePrePopFP = 4;
 #elif defined(JS_CODEGEN_NONE)
 # if defined(DEBUG)
@@ -281,7 +281,7 @@ GenerateProfilingPrologue(MacroAssembler& masm, unsigned framePushed, ExitReason
     // randomly inserted between two instructions.
     {
 #if defined(JS_CODEGEN_ARM)
-        AutoForbidPools afp(&masm, /* number of instructions in scope = */ 6);
+        AutoForbidPools afp(&masm, /* number of instructions in scope = */ 7);
 #endif
 
         offsets->begin = masm.currentOffset();
@@ -289,7 +289,7 @@ GenerateProfilingPrologue(MacroAssembler& masm, unsigned framePushed, ExitReason
         PushRetAddr(masm);
         MOZ_ASSERT_IF(!masm.oom(), PushedRetAddr == masm.currentOffset() - offsets->begin);
 
-        masm.loadWasmActivationFromTls(scratch);
+        masm.loadWasmActivationFromSymbolicAddress(scratch);
         masm.push(Address(scratch, WasmActivation::offsetOfFP()));
         MOZ_ASSERT_IF(!masm.oom(), PushedFP == masm.currentOffset() - offsets->begin);
 
@@ -318,7 +318,7 @@ GenerateProfilingEpilogue(MacroAssembler& masm, unsigned framePushed, ExitReason
     if (framePushed)
         masm.addToStackPtr(Imm32(framePushed));
 
-    masm.loadWasmActivationFromTls(scratch);
+    masm.loadWasmActivationFromSymbolicAddress(scratch);
 
     if (reason != ExitReason::None) {
         masm.store32(Imm32(int32_t(ExitReason::None)),

js/src/asmjs/WasmJS.cpp

@@ -55,6 +55,13 @@ wasm::HasCompilerSupport(ExclusiveContext* cx)
     if (!wasm::HaveSignalHandlers())
         return false;
 
+#if defined(JS_CODEGEN_ARM)
+    // movw/t are required for the loadWasmActivationFromSymbolicAddress in
+    // GenerateProfilingPrologue/Epilogue to avoid using the constant pool.
+    if (!HasMOVWT())
+        return false;
+#endif
+
 #if defined(JS_CODEGEN_NONE) || defined(JS_CODEGEN_ARM64)
     return false;
 #else

js/src/jit-test/tests/wasm/no-movwt.js

@@ -0,0 +1,8 @@
+setARMHwCapFlags('vfp');
+
+if (typeof WebAssembly !== "undefined") {
+    var i = new WebAssembly.Instance(
+                new WebAssembly.Module(
+                    wasmTextToBinary('(module (func (export "") (result i32) (i32.const 42)))')));
+    assertEq(i.exports[""](), 42);
+}