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Sanjoy Das ead2d1fbe0 [Statepoints] Support for "patchable" statepoints.
Summary:
This change adds two new parameters to the statepoint intrinsic, `i64 id`
and `i32 num_patch_bytes`.  `id` gets propagated to the ID field
in the generated StackMap section.  If the `num_patch_bytes` is
non-zero then the statepoint is lowered to `num_patch_bytes` bytes of
nops instead of a call (the spill and reload code remains unchanged).
A non-zero `num_patch_bytes` is useful in situations where a language
runtime requires complete control over how a call is lowered.

This change brings statepoints one step closer to patchpoints.  With
some additional work (that is not part of this patch) it should be
possible to get rid of `TargetOpcode::STATEPOINT` altogether.

PlaceSafepoints generates `statepoint` wrappers with `id` set to
`0xABCDEF00` (the old default value for the ID reported in the stackmap)
and `num_patch_bytes` set to `0`.  This can be made more sophisticated
later.

Reviewers: reames, pgavlin, swaroop.sridhar, AndyAyers

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D9546

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237214 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-12 23:52:24 +00:00

38 lines
1.7 KiB
LLVM

; RUN: opt %s -rewrite-statepoints-for-gc -spp-print-base-pointers -S 2>&1 | FileCheck %s
; CHECK: derived %next_element_ptr base %array_obj
define i32 @null_in_array(i64 addrspace(1)* %array_obj) gc "statepoint-example" {
entry:
%array_len_pointer.i64 = getelementptr i64, i64 addrspace(1)* %array_obj, i32 1
%array_len_pointer.i32 = bitcast i64 addrspace(1)* %array_len_pointer.i64 to i32 addrspace(1)*
%array_len = load i32, i32 addrspace(1)* %array_len_pointer.i32
%array_elems = bitcast i32 addrspace(1)* %array_len_pointer.i32 to i64 addrspace(1)* addrspace(1)*
br label %loop_check
loop_check:
%index = phi i32 [ 0, %entry ], [ %next_index, %loop_back ]
%current_element_ptr = phi i64 addrspace(1)* addrspace(1)* [ %array_elems, %entry ], [ %next_element_ptr, %loop_back ]
%index_lt = icmp ult i32 %index, %array_len
br i1 %index_lt, label %check_for_null, label %not_found
check_for_null:
%current_element = load i64 addrspace(1)*, i64 addrspace(1)* addrspace(1)* %current_element_ptr
%is_null = icmp eq i64 addrspace(1)* %current_element, null
br i1 %is_null, label %found, label %loop_back
loop_back:
%next_element_ptr = getelementptr i64 addrspace(1)*, i64 addrspace(1)* addrspace(1)* %current_element_ptr, i32 1
%next_index = add i32 %index, 1
%safepoint_token = call i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @do_safepoint, i32 0, i32 0, i32 0, i32 5, i32 0, i32 -1, i32 0, i32 0, i32 0)
br label %loop_check
not_found:
ret i32 -1
found:
ret i32 %index
}
declare void @do_safepoint()
declare i32 @llvm.experimental.gc.statepoint.p0f_isVoidf(i64, i32, void ()*, i32, i32, ...)