[gc.statepoint] Change gc.statepoint intrinsic's return type to token type instead of i32 type

Summary: This patch changes gc.statepoint intrinsic's return type to token type instead of i32 type. Using token types could prevent LLVM to merge different gc.statepoint nodes into PHI nodes and cause further problems with gc relocations. The patch also changes the way on how gc.relocate and gc.result look for their corresponding gc.statepoint on unwind path. The current implementation uses the selector value extracted from a { i8*, i32 } landingpad as a hook to find the gc.statepoint, while the patch directly uses a token type landingpad (http://reviews.llvm.org/D15405) to find the gc.statepoint. 

Reviewers: sanjoy, JosephTremoulet, pgavlin, igor-laevsky, mjacob

Subscribers: reames, mjacob, sanjoy, llvm-commits

Differential Revision: http://reviews.llvm.org/D15662

llvm-svn: 256443
diff --git a/llvm/docs/Statepoints.rst b/llvm/docs/Statepoints.rst
index 26c597c..442b1c2 100644
--- a/llvm/docs/Statepoints.rst
+++ b/llvm/docs/Statepoints.rst
@@ -142,8 +142,8 @@
 
   define i8 addrspace(1)* @test1(i8 addrspace(1)* %obj) 
          gc "statepoint-example" {
-    %0 = call i32 (i64, i32, void ()*, i32, i32, ...)* @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @foo, i32 0, i32 0, i32 0, i32 0, i8 addrspace(1)* %obj)
-    %obj.relocated = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(i32 %0, i32 7, i32 7)
+    %0 = call token (i64, i32, void ()*, i32, i32, ...)* @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @foo, i32 0, i32 0, i32 0, i32 0, i8 addrspace(1)* %obj)
+    %obj.relocated = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token %0, i32 7, i32 7)
     ret i8 addrspace(1)* %obj.relocated
   }
 
@@ -242,9 +242,9 @@
   define i8 addrspace(1)* @test1(i8 addrspace(1)* %obj) 
          gc "statepoint-example" {
     %gep = getelementptr i8, i8 addrspace(1)* %obj, i64 20000
-    %token = call i32 (i64, i32, void ()*, i32, i32, ...)* @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @foo, i32 0, i32 0, i32 0, i32 0, i8 addrspace(1)* %obj, i8 addrspace(1)* %gep)
-    %obj.relocated = call i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(i32 %token, i32 7, i32 7)
-    %gep.relocated = call i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(i32 %token, i32 7, i32 8)
+    %token = call token (i64, i32, void ()*, i32, i32, ...)* @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @foo, i32 0, i32 0, i32 0, i32 0, i8 addrspace(1)* %obj, i8 addrspace(1)* %gep)
+    %obj.relocated = call i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token %token, i32 7, i32 7)
+    %gep.relocated = call i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token %token, i32 7, i32 8)
     %p = getelementptr i8, i8 addrspace(1)* %gep, i64 -20000
     ret i8 addrspace(1)* %p
   }
@@ -288,8 +288,8 @@
   define i8 addrspace(1)* @test1(i8 addrspace(1) *%obj)
          gc "hypothetical-gc" {
 
-    %0 = call i32 (i64, i32, void ()*, i32, i32, ...)* @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @foo, i32 0, i32 1, i32* @Flag, i32 0, i8 addrspace(1)* %obj)
-    %obj.relocated = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(i32 %0, i32 7, i32 7)
+    %0 = call token (i64, i32, void ()*, i32, i32, ...)* @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @foo, i32 0, i32 1, i32* @Flag, i32 0, i8 addrspace(1)* %obj)
+    %obj.relocated = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token %0, i32 7, i32 7)
     ret i8 addrspace(1)* %obj.relocated
   }
 
@@ -342,7 +342,7 @@
 
 ::
 
-      declare i32
+      declare token
         @llvm.experimental.gc.statepoint(i64 <id>, i32 <num patch bytes>,
                        func_type <target>, 
                        i64 <#call args>, i64 <flags>,
@@ -456,7 +456,7 @@
 ::
 
       declare type*
-        @llvm.experimental.gc.result(i32 %statepoint_token)
+        @llvm.experimental.gc.result(token %statepoint_token)
 
 Overview:
 """""""""
@@ -472,7 +472,7 @@
 
 The first and only argument is the ``gc.statepoint`` which starts
 the safepoint sequence of which this ``gc.result`` is a part.
-Despite the typing of this as a generic i32, *only* the value defined
+Despite the typing of this as a generic token, *only* the value defined 
 by a ``gc.statepoint`` is legal here.
 
 Semantics:
@@ -496,7 +496,7 @@
 ::
 
       declare <pointer type>
-        @llvm.experimental.gc.relocate(i32 %statepoint_token, 
+        @llvm.experimental.gc.relocate(token %statepoint_token, 
                                        i32 %base_offset, 
                                        i32 %pointer_offset)
 
@@ -511,7 +511,7 @@
 
 The first argument is the ``gc.statepoint`` which starts the
 safepoint sequence of which this ``gc.relocation`` is a part.
-Despite the typing of this as a generic i32, *only* the value defined
+Despite the typing of this as a generic token, *only* the value defined 
 by a ``gc.statepoint`` is legal here.
 
 The second argument is an index into the statepoints list of arguments
@@ -643,7 +643,7 @@
 
   define i8 addrspace(1)* @test1(i8 addrspace(1)* %obj) 
          gc "statepoint-example" {
-    call i32 (i64, i32, void ()*, i32, i32, ...)* @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 2882400000, i32 0, void ()* @foo, i32 0, i32 0, i32 0, i32 5, i32 0, i32 -1, i32 0, i32 0, i32 0)
+    call token (i64, i32, void ()*, i32, i32, ...)* @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 2882400000, i32 0, void ()* @foo, i32 0, i32 0, i32 0, i32 5, i32 0, i32 -1, i32 0, i32 0, i32 0)
     ret i8 addrspace(1)* %obj
   }
 
@@ -653,8 +653,8 @@
 
   define i8 addrspace(1)* @test1(i8 addrspace(1)* %obj) 
          gc "statepoint-example" {
-    %0 = call i32 (i64, i32, void ()*, i32, i32, ...)* @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 2882400000, i32 0, void ()* @foo, i32 0, i32 0, i32 0, i32 5, i32 0, i32 -1, i32 0, i32 0, i32 0, i8 addrspace(1)* %obj)
-    %obj.relocated = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(i32 %0, i32 12, i32 12)
+    %0 = call token (i64, i32, void ()*, i32, i32, ...)* @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 2882400000, i32 0, void ()* @foo, i32 0, i32 0, i32 0, i32 5, i32 0, i32 -1, i32 0, i32 0, i32 0, i8 addrspace(1)* %obj)
+    %obj.relocated = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token %0, i32 12, i32 12)
     ret i8 addrspace(1)* %obj.relocated
   }
 
@@ -717,8 +717,8 @@
 .. code-block:: llvm
 
   define void @test() gc "statepoint-example" {
-    %safepoint_token = call i32 (i64, i32, void ()*, i32, i32, ...)* @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 2882400000, i32 0, void ()* @do_safepoint, i32 0, i32 0, i32 0, i32 0)
-    %safepoint_token1 = call i32 (i64, i32, void ()*, i32, i32, ...)* @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 2882400000, i32 0, void ()* @foo, i32 0, i32 0, i32 0, i32 0)
+    %safepoint_token = call token (i64, i32, void ()*, i32, i32, ...)* @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 2882400000, i32 0, void ()* @do_safepoint, i32 0, i32 0, i32 0, i32 0)
+    %safepoint_token1 = call token (i64, i32, void ()*, i32, i32, ...)* @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 2882400000, i32 0, void ()* @foo, i32 0, i32 0, i32 0, i32 0)
     ret void
   }