Changeset 159288 in webkit for trunk/Source/JavaScriptCore/offlineasm/sh4.rb

Timestamp:

Nov 14, 2013, 8:52:48 AM (12 years ago)

Author:

[email protected]

Message:

REGRESSION (r159276): Fix lots of crashes for sh4 architecture.
​https://bugs.webkit.org/show_bug.cgi?id=124347

Patch by Julien Brianceau <​[email protected]> on 2013-11-14
Reviewed by Michael Saboff.

Since r159276, we have (t4 == a0 == r4) and (t5 == a1 == r5) in LLINT for sh4.
This leads to argument register trampling in cCallX macros, especially with cCall2
macro when arg1 == t4.

• llint/LowLevelInterpreter32_64.asm: Use a new "setargs" pseudo-op to setup arguments for sh4.
• offlineasm/instructions.rb:
• offlineasm/sh4.rb: Lower "setargs" pseudo-op to setup argument registers and prevent register trampling issues.

File:

• trunk/Source/JavaScriptCore/offlineasm/sh4.rb (modified) (3 diffs)

trunk/Source/JavaScriptCore/offlineasm/sh4.rb

@@ -564 +564 @@
 
 
+#
+# Lowering of argument setup for SH4.
+# This phase avoids argument register trampling. For example, if a0 == t4:
+#
+# setargs t1, t4
+#
+# becomes:
+#
+# move t4, a1
+# move t1, a0
+#
+
+def sh4LowerArgumentSetup(list)
+    a0 = RegisterID.forName(codeOrigin, "a0")
+    a1 = RegisterID.forName(codeOrigin, "a1")
+    a2 = RegisterID.forName(codeOrigin, "a2")
+    a3 = RegisterID.forName(codeOrigin, "a3")
+    newList = []
+    list.each {
+        | node |
+        if node.is_a? Instruction
+            case node.opcode
+            when "setargs"
+                if node.operands.size == 2
+                    if node.operands[1].sh4Operand != a0.sh4Operand
+                        newList << Instruction.new(codeOrigin, "move", [node.operands[0], a0])
+                        newList << Instruction.new(codeOrigin, "move", [node.operands[1], a1])
+                    elsif node.operands[0].sh4Operand != a1.sh4Operand
+                        newList << Instruction.new(codeOrigin, "move", [node.operands[1], a1])
+                        newList << Instruction.new(codeOrigin, "move", [node.operands[0], a0])
+                    else
+                        # As (operands[0] == a1) and (operands[1] == a0), we just need to swap a0 and a1.
+                        newList << Instruction.new(codeOrigin, "xori", [a0, a1])
+                        newList << Instruction.new(codeOrigin, "xori", [a1, a0])
+                        newList << Instruction.new(codeOrigin, "xori", [a0, a1])
+                    end
+                elsif node.operands.size == 4
+                    # FIXME: We just raise an error if something is likely to go wrong for now.
+                    # It would be better to implement a recovering algorithm.
+                    if (node.operands[0].sh4Operand == a1.sh4Operand) or
+                        (node.operands[0].sh4Operand == a2.sh4Operand) or
+                        (node.operands[0].sh4Operand == a3.sh4Operand) or
+                        (node.operands[1].sh4Operand == a0.sh4Operand) or
+                        (node.operands[1].sh4Operand == a2.sh4Operand) or
+                        (node.operands[1].sh4Operand == a3.sh4Operand) or
+                        (node.operands[2].sh4Operand == a0.sh4Operand) or
+                        (node.operands[2].sh4Operand == a1.sh4Operand) or
+                        (node.operands[2].sh4Operand == a3.sh4Operand) or
+                        (node.operands[3].sh4Operand == a0.sh4Operand) or
+                        (node.operands[3].sh4Operand == a1.sh4Operand) or
+                        (node.operands[3].sh4Operand == a2.sh4Operand)
+                        raise "Potential argument register trampling detected."
+                    end
+
+                    newList << Instruction.new(codeOrigin, "move", [node.operands[0], a0])
+                    newList << Instruction.new(codeOrigin, "move", [node.operands[1], a1])
+                    newList << Instruction.new(codeOrigin, "move", [node.operands[2], a2])
+                    newList << Instruction.new(codeOrigin, "move", [node.operands[3], a3])
+                else
+                    raise "Invalid operands number (#{node.operands.size}) for setargs"
+                end
+            else
+                newList << node
+            end
+        else
+            newList << node
+        end
+    }
+    newList
+end
+
+
 class Sequence
     def getModifiedListSH4
@@ -614 +686 @@
 
         result = sh4LowerConstPool(result)
+        result = sh4LowerArgumentSetup(result)
 
         return result
@@ -884 +957 @@
                     $asm.puts "mov.l #{operands[0].labelref.asmLabel}, #{operands[1].sh4Operand}"
                 end
-            else
+            elsif operands[0].sh4Operand != operands[1].sh4Operand
                 $asm.puts "mov #{sh4Operands(operands)}"
             end