From e77491226adefca4fe5aebb1e689c9d04903cc90 Mon Sep 17 00:00:00 2001
From: Juergen Ributzka <juergen@apple.com>
Date: Mon, 16 Dec 2013 22:05:32 +0000
Subject: [Stackmap] Allow WebKit_JS calling convention to store 4 byte sized
 and aligned arguments.

This allows the WebKit_JS calling convention to perform partial writes on a 4
byte granularity to stack slots.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@197431 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/X86/X86CallingConv.td | 13 ++++++++-----
 test/CodeGen/X86/patchpoint.ll   | 36 +++++++++++++++++++++++++++++++++++-
 2 files changed, 43 insertions(+), 6 deletions(-)

diff --git a/lib/Target/X86/X86CallingConv.td b/lib/Target/X86/X86CallingConv.td
index ef8caa0290..6185c1cd38 100644
--- a/lib/Target/X86/X86CallingConv.td
+++ b/lib/Target/X86/X86CallingConv.td
@@ -358,12 +358,15 @@ def CC_X86_64_WebKit_JS : CallingConv<[
   CCIfType<[i8, i16], CCPromoteToType<i32>>,
 
   // Only the first integer argument is passed in register.
-  CCIfType<[i32], CCAssignToReg<[EDI]>>,
-  CCIfType<[i64], CCAssignToReg<[RDI]>>,
+  CCIfType<[i32], CCAssignToReg<[EAX]>>,
+  CCIfType<[i64], CCAssignToReg<[RAX]>>,
 
-  // Integer/FP values are always stored in stack slots that are 8 bytes in size
-  // and 8-byte aligned.
-  CCIfType<[i32, i64, f32, f64], CCAssignToStack<8, 8>>
+  // The remaining integer arguments are passed on the stack. 32bit integer and
+  // floating-point arguments are aligned to 4 byte and stored in 4 byte slots.
+  // 64bit integer and floating-point arguments are aligned to 8 byte and stored
+  // in 8 byte stack slots.
+  CCIfType<[i32, f32], CCAssignToStack<4, 4>>,
+  CCIfType<[i64, f64], CCAssignToStack<8, 8>>
 ]>;
 
 // No explicit register is specified for the AnyReg calling convention. The
diff --git a/test/CodeGen/X86/patchpoint.ll b/test/CodeGen/X86/patchpoint.ll
index ef30cf78bf..62b12732de 100644
--- a/test/CodeGen/X86/patchpoint.ll
+++ b/test/CodeGen/X86/patchpoint.ll
@@ -46,7 +46,7 @@ entry:
 ; CHECK-LABEL: jscall_patchpoint_codegen:
 ; CHECK:      Ltmp
 ; CHECK:      movq %r{{.+}}, (%rsp)
-; CHECK:      movq %r{{.+}}, %rdi
+; CHECK:      movq %r{{.+}}, %rax
 ; CHECK:      Ltmp
 ; CHECK-NEXT: movabsq $-559038736, %r11
 ; CHECK-NEXT: callq *%r11
@@ -59,6 +59,40 @@ entry:
   ret void
 }
 
+; Test if the arguments are properly aligned and that we don't store undef arguments.
+define i64 @jscall_patchpoint_codegen2(i64 %callee) {
+entry:
+; CHECK-LABEL: jscall_patchpoint_codegen2:
+; CHECK:      Ltmp
+; CHECK:      movq $6, 24(%rsp)
+; CHECK-NEXT: movl $4, 16(%rsp)
+; CHECK-NEXT: movq $2, (%rsp)
+; CHECK:      Ltmp
+; CHECK-NEXT: movabsq $-559038736, %r11
+; CHECK-NEXT: callq *%r11
+  %call = inttoptr i64 -559038736 to i8*
+  %result = call webkit_jscc i64 (i64, i32, i8*, i32, ...)* @llvm.experimental.patchpoint.i64(i64 7, i32 15, i8* %call, i32 6, i64 %callee, i64 2, i64 undef, i32 4, i32 undef, i64 6)
+  ret i64 %result
+}
+
+; Test if the arguments are properly aligned and that we don't store undef arguments.
+define i64 @jscall_patchpoint_codegen3(i64 %callee) {
+entry:
+; CHECK-LABEL: jscall_patchpoint_codegen3:
+; CHECK:      Ltmp
+; CHECK:      movq $10, 48(%rsp)
+; CHECK-NEXT: movl  $8, 36(%rsp)
+; CHECK-NEXT: movq  $6, 24(%rsp)
+; CHECK-NEXT: movl  $4, 16(%rsp)
+; CHECK-NEXT: movq  $2, (%rsp)
+; CHECK:      Ltmp
+; CHECK-NEXT: movabsq $-559038736, %r11
+; CHECK-NEXT: callq *%r11
+  %call = inttoptr i64 -559038736 to i8*
+  %result = call webkit_jscc i64 (i64, i32, i8*, i32, ...)* @llvm.experimental.patchpoint.i64(i64 7, i32 15, i8* %call, i32 10, i64 %callee, i64 2, i64 undef, i32 4, i32 undef, i64 6, i32 undef, i32 8, i32 undef, i64 10)
+  ret i64 %result
+}
+
 ; Test patchpoints reusing the same TargetConstant.
 ; <rdar:15390785> Assertion failed: (CI.getNumArgOperands() >= NumArgs + 4)
 ; There is no way to verify this, since it depends on memory allocation.
-- 
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