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mail/thunderbird/files/patch-bug1375074
- This file was added.
commit fc25eb4380d0 | |||||
Author: Lars T Hansen <lhansen@mozilla.com> | |||||
Date: Wed Feb 28 13:57:52 2018 +0100 | |||||
Bug 1375074 - Save and restore non-volatile x28 on ARM64 for generated unboxed object constructor. r=sstangl | |||||
--HG-- | |||||
extra : rebase_source : 4a2824b23cf7453d07c962123f780c0ff2fd5292 | |||||
extra : source : dec6ab6522a4eb4b3c2defc5078b38ed904f3383 | |||||
--- | |||||
js/src/jit-test/tests/bug1375074.js | 18 ++++++++++++++++++ | |||||
js/src/vm/UnboxedObject.cpp | 25 ++++++++++++++++++++++++- | |||||
2 files changed, 42 insertions(+), 1 deletion(-) | |||||
diff --git js/src/jit-test/tests/bug1375074.js js/src/jit-test/tests/bug1375074.js | |||||
new file mode 100644 | |||||
index 0000000000000..8bf01d96903fc | |||||
--- /dev/null | |||||
+++ mozilla/js/src/jit-test/tests/bug1375074.js | |||||
@@ -0,0 +1,18 @@ | |||||
+// This forces the VM to start creating unboxed objects and thus stresses a | |||||
+// particular path into generated code for a specialized unboxed object | |||||
+// constructor. | |||||
+ | |||||
+var K = 2000; // 2000 should be plenty | |||||
+var s = "["; | |||||
+var i; | |||||
+for ( i=0; i < K-1; i++ ) | |||||
+ s = s + `{"i":${i}},`; | |||||
+s += `{"i":${i}}]`; | |||||
+var v = JSON.parse(s); | |||||
+ | |||||
+assertEq(v.length == K, true); | |||||
+ | |||||
+for ( i=0; i < K; i++) { | |||||
+ assertEq(v[i] instanceof Object, true); | |||||
+ assertEq(v[i].i, i); | |||||
+} | |||||
diff --git js/src/vm/UnboxedObject.cpp js/src/vm/UnboxedObject.cpp | |||||
index c8c178965c488..5badf328ede4f 100644 | |||||
--- mozilla/js/src/vm/UnboxedObject.cpp | |||||
+++ mozilla/js/src/vm/UnboxedObject.cpp | |||||
@@ -95,7 +95,15 @@ UnboxedLayout::makeConstructorCode(JSContext* cx, HandleObjectGroup group) | |||||
#endif | |||||
#ifdef JS_CODEGEN_ARM64 | |||||
- // ARM64 communicates stack address via sp, but uses a pseudo-sp for addressing. | |||||
+ // ARM64 communicates stack address via sp, but uses a pseudo-sp (PSP) for | |||||
+ // addressing. The register we use for PSP may however also be used by | |||||
+ // calling code, and it is nonvolatile, so save it. Do this as a special | |||||
+ // case first because the generic save/restore code needs the PSP to be | |||||
+ // initialized already. | |||||
+ MOZ_ASSERT(PseudoStackPointer64.Is(masm.GetStackPointer64())); | |||||
+ masm.Str(PseudoStackPointer64, vixl::MemOperand(sp, -16, vixl::PreIndex)); | |||||
+ | |||||
+ // Initialize the PSP from the SP. | |||||
masm.initStackPtr(); | |||||
#endif | |||||
@@ -233,7 +241,22 @@ UnboxedLayout::makeConstructorCode(JSContext* cx, HandleObjectGroup group) | |||||
masm.pop(ScratchDoubleReg); | |||||
masm.PopRegsInMask(savedNonVolatileRegisters); | |||||
+#ifdef JS_CODEGEN_ARM64 | |||||
+ // Now restore the value that was in the PSP register on entry, and return. | |||||
+ | |||||
+ // Obtain the correct SP from the PSP. | |||||
+ masm.Mov(sp, PseudoStackPointer64); | |||||
+ | |||||
+ // Restore the saved value of the PSP register, this value is whatever the | |||||
+ // caller had saved in it, not any actual SP value, and it must not be | |||||
+ // overwritten subsequently. | |||||
+ masm.Ldr(PseudoStackPointer64, vixl::MemOperand(sp, 16, vixl::PostIndex)); | |||||
+ | |||||
+ // Perform a plain Ret(), as abiret() will move SP <- PSP and that is wrong. | |||||
+ masm.Ret(vixl::lr); | |||||
+#else | |||||
masm.abiret(); | |||||
+#endif | |||||
masm.bind(&failureStoreOther); | |||||