[v8-dev] Simplify stackframe of construct stub on ARM and MIPS. (issue 9348058)

Wed, 08 Feb 2012 08:45:38 -0800 

Reviewers: Erik Corry,

Description:
Simplify stackframe of construct stub on ARM and MIPS.

This unifies the stackframe layout of the generic constructor stub to be
in sync with ia32 and x64. There was an unecessary copy of the construct
function saved on the stack which wasn't used at all.

[email protected]


Please review this at https://chromiumcodereview.appspot.com/9348058/

SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge

Affected files:
  M src/arm/builtins-arm.cc
  M src/mips/builtins-mips.cc


Index: src/arm/builtins-arm.cc
diff --git a/src/arm/builtins-arm.cc b/src/arm/builtins-arm.cc
index 186d06e3f095b3a11a17561b646711e8ef0ce58f..50b6bce30b7dddc4caeec098dd1e38464839d610 100644 
--- a/src/arm/builtins-arm.cc
+++ b/src/arm/builtins-arm.cc
@@ -895,23 +895,15 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm, 
     // r4: JSObject
     __ bind(&allocated);
     __ push(r4);
+    __ push(r4);

-    // Push the function and the allocated receiver from the stack.
-    // sp[0]: receiver (newly allocated object)
-    // sp[1]: constructor function
-    // sp[2]: number of arguments (smi-tagged)
-    __ ldr(r1, MemOperand(sp, kPointerSize));
-    __ push(r1);  // Constructor function.
-    __ push(r4);  // Receiver.
-
-    // Reload the number of arguments from the stack.
-    // r1: constructor function
+    // Reload the number of arguments and the constructor from the stack.
     // sp[0]: receiver
-    // sp[1]: constructor function
-    // sp[2]: receiver
-    // sp[3]: constructor function
-    // sp[4]: number of arguments (smi-tagged)
-    __ ldr(r3, MemOperand(sp, 4 * kPointerSize));
+    // sp[1]: receiver
+    // sp[2]: constructor function
+    // sp[3]: number of arguments (smi-tagged)
+    __ ldr(r1, MemOperand(sp, 2 * kPointerSize));
+    __ ldr(r3, MemOperand(sp, 3 * kPointerSize));

     // Set up pointer to last argument.
     __ add(r2, fp, Operand(StandardFrameConstants::kCallerSPOffset));
@@ -921,14 +913,13 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm, 

     // Copy arguments and receiver to the expression stack.
     // r0: number of arguments
-    // r2: address of last argument (caller sp)
     // r1: constructor function
+    // r2: address of last argument (caller sp)
     // r3: number of arguments (smi-tagged)
     // sp[0]: receiver
-    // sp[1]: constructor function
-    // sp[2]: receiver
-    // sp[3]: constructor function
-    // sp[4]: number of arguments (smi-tagged)
+    // sp[1]: receiver
+    // sp[2]: constructor function
+    // sp[3]: number of arguments (smi-tagged)
     Label loop, entry;
     __ b(&entry);
     __ bind(&loop);
@@ -954,13 +945,6 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm, 
                         NullCallWrapper(), CALL_AS_METHOD);
     }

-    // Pop the function from the stack.
-    // sp[0]: constructor function
-    // sp[2]: receiver
-    // sp[3]: constructor function
-    // sp[4]: number of arguments (smi-tagged)
-    __ pop();
-
     // Restore context from the frame.
     // r0: result
     // sp[0]: receiver
Index: src/mips/builtins-mips.cc
diff --git a/src/mips/builtins-mips.cc b/src/mips/builtins-mips.cc
index d122e9a9f90854c9d6ea0a6d1b727af3304a4bd4..e8de833f939cd3560f84f4fa380b033bbf42dc8c 100644 
--- a/src/mips/builtins-mips.cc
+++ b/src/mips/builtins-mips.cc
@@ -924,22 +924,15 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm, 
     // t4: JSObject
     __ bind(&allocated);
     __ push(t4);
-
-    // Push the function and the allocated receiver from the stack.
-    // sp[0]: receiver (newly allocated object)
-    // sp[1]: constructor function
-    // sp[2]: number of arguments (smi-tagged)
-    __ lw(a1, MemOperand(sp, kPointerSize));
-    __ MultiPushReversed(a1.bit() | t4.bit());
+    __ push(t4);

     // Reload the number of arguments from the stack.
-    // a1: constructor function
     // sp[0]: receiver
-    // sp[1]: constructor function
-    // sp[2]: receiver
-    // sp[3]: constructor function
-    // sp[4]: number of arguments (smi-tagged)
-    __ lw(a3, MemOperand(sp, 4 * kPointerSize));
+    // sp[1]: receiver
+    // sp[2]: constructor function
+    // sp[3]: number of arguments (smi-tagged)
+    __ lw(a1, MemOperand(sp, 2 * kPointerSize));
+    __ lw(a3, MemOperand(sp, 3 * kPointerSize));

     // Set up pointer to last argument.
     __ Addu(a2, fp, Operand(StandardFrameConstants::kCallerSPOffset));
@@ -953,10 +946,9 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm, 
     // a2: address of last argument (caller sp)
     // a3: number of arguments (smi-tagged)
     // sp[0]: receiver
-    // sp[1]: constructor function
-    // sp[2]: receiver
-    // sp[3]: constructor function
-    // sp[4]: number of arguments (smi-tagged)
+    // sp[1]: receiver
+    // sp[2]: constructor function
+    // sp[3]: number of arguments (smi-tagged)
     Label loop, entry;
     __ jmp(&entry);
     __ bind(&loop);
@@ -984,14 +976,6 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm, 
                         NullCallWrapper(), CALL_AS_METHOD);
     }

-    // Pop the function from the stack.
-    // v0: result
-    // sp[0]: constructor function
-    // sp[2]: receiver
-    // sp[3]: constructor function
-    // sp[4]: number of arguments (smi-tagged)
-    __ Pop();
-
     // Restore context from the frame.
     __ lw(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));



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