Changeset 195236 in webkit

Timestamp:

Jan 18, 2016 1:07:08 PM (8 years ago)

Author:

commit-queue@webkit.org

Message:

[MIPS] LLInt: fix calculation of Global Offset Table
​https://bugs.webkit.org/show_bug.cgi?id=150381

Offlineasm adds a .cpload $t9 when we create a label in MIPS, which
computes address of GOT. However, this instruction requires $t9 to
contain address of current function. So we need to set $t9 to pcBase,
otherwise GOT-related calculations will be invalid.

Since offlineasm does not allow direct move to $t9 on MIPS, added new
instruction setcallreg which does exactly that.

Patch by Konstantin Tokarev <Konstantin Tokarev> on 2016-01-18
Reviewed by Michael Saboff.

• llint/LowLevelInterpreter.asm:
• offlineasm/instructions.rb:
• offlineasm/mips.rb:

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• llint/LowLevelInterpreter.asm (modified) (1 diff)
• offlineasm/instructions.rb (modified) (1 diff)
• offlineasm/mips.rb (modified) (1 diff)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2016-01-18  Konstantin Tokarev  <annulen@yandex.ru>
+
+        [MIPS] LLInt: fix calculation of Global Offset Table
+        https://bugs.webkit.org/show_bug.cgi?id=150381
+
+        Offlineasm adds a .cpload $t9 when we create a label in MIPS, which
+        computes address of GOT. However, this instruction requires $t9 to
+        contain address of current function. So we need to set $t9 to pcBase,
+        otherwise GOT-related calculations will be invalid.
+
+        Since offlineasm does not allow direct move to $t9 on MIPS, added new
+        instruction setcallreg which does exactly that.
+
+        Reviewed by Michael Saboff.
+
+        * llint/LowLevelInterpreter.asm:
+        * offlineasm/instructions.rb:
+        * offlineasm/mips.rb:
+
 2016-01-18  Csaba Osztrogonác  <ossy@webkit.org>
 

trunk/Source/JavaScriptCore/llint/LowLevelInterpreter.asm

@@ -1088 +1088 @@
         elsif MIPS
             la _relativePCBase, pcBase
+            setcallreg pcBase # needed to set $t9 to the right value for the .cpload created by the label.
         _relativePCBase:
         elsif SH4

trunk/Source/JavaScriptCore/offlineasm/instructions.rb

@@ -285 +285 @@
     "movz",
     "movn",
+    "setcallreg",
     "slt",
     "sltu",

trunk/Source/JavaScriptCore/offlineasm/mips.rb

@@ -1034 +1034 @@
         when "movn"
             $asm.puts "movn #{operands[0].mipsOperand}, #{operands[1].mipsOperand}, #{operands[2].mipsOperand}"
+        when "setcallreg"
+            $asm.puts "move #{MIPS_CALL_REG.mipsOperand}, #{operands[0].mipsOperand}"
         when "slt", "sltb"
             $asm.puts "slt #{operands[0].mipsOperand}, #{operands[1].mipsOperand}, #{operands[2].mipsOperand}"