Changeset 289740 in webkit for trunk/Source/JavaScriptCore/assembler/CPU.h

Timestamp:

Feb 14, 2022, 10:39:19 AM (3 years ago)

Author:

[email protected]

Message:

CallLinkInfo::emitFastPathImpl() should avoid external scratch register use on RISCV64
​https://bugs.webkit.org/show_bug.cgi?id=236064

Patch by Zan Dobersek <​[email protected]> on 2022-02-14
Reviewed by Yusuke Suzuki.

Avoid external scratch register usage in CallLinkInfo::emitFastPathImpl()
for RISCV64 since the scratch register ends up having to be used in the
branchTestPtr implementation of RISCV64's MacroAssembler.

The RISCV64-specific alternative is to suffer resolving and loading from
the callee address for both branching operations. Other platforms
continue to operate with the external scratch register as they either
use a wider set of scratch registers or don't even have to use scratch
registers for the load and branching operations used here.

• assembler/CPU.h: Add isRISCV64(). Also impose a more sensible order.

(JSC::isMIPS):
(JSC::isRISCV64):

• bytecode/CallLinkInfo.cpp:

(JSC::CallLinkInfo::emitFastPathImpl):

File:

• trunk/Source/JavaScriptCore/assembler/CPU.h (modified) (2 diffs)

trunk/Source/JavaScriptCore/assembler/CPU.h

@@ -79 +79 @@
 }
 
+constexpr bool isMIPS()
+{
+#if CPU(MIPS)
+    return true;
+#else
+    return false;
+#endif
+}
+
+constexpr bool isRISCV64()
+{
+#if CPU(RISCV64)
+    return true;
+#else
+    return false;
+#endif
+}
+
 constexpr bool is64Bit()
 {
@@ -101 +119 @@
 {
     return !isAddress64Bit();
-}
-
-constexpr bool isMIPS()
-{
-#if CPU(MIPS)
-    return true;
-#else
-    return false;
-#endif
 }