| ; RUN: opt -O3 -S < %s | FileCheck --check-prefix=CHECK-OPT %s |
| ; RUN: llc -verify-machineinstrs < %s | FileCheck --check-prefix=CHECK-LLC %s |
| ; These tests are targetted at making sure we don't retain information |
| ; about memory which contains potential gc references across a statepoint. |
| ; They're carefully written to only outlaw forwarding of references. |
| ; Depending on the collector, forwarding non-reference fields or |
| ; constant null references may be perfectly legal. (If unimplemented.) |
| ; The general structure of these tests is: |
| ; - learn a fact about memory (via an assume) |
| ; - cross a statepoint |
| ; - check the same fact about memory (which we no longer know) |
| |
| target datalayout = "e-i64:64-f80:128-n8:16:32:64-S128" |
| target triple = "x86_64-pc-linux-gnu" |
| |
| ; If not at a statepoint, we could forward known memory values |
| ; across this call. |
| declare void @func() readonly |
| |
| ;; Forwarding the value of a pointer load is invalid since it may have |
| ;; changed at the safepoint. Forwarding a non-gc pointer value would |
| ;; be valid, but is not currently implemented. |
| define i1 @test_load_forward(i32 addrspace(1)* addrspace(1)* %p) gc "statepoint-example" { |
| entry: |
| %before = load i32 addrspace(1)*, i32 addrspace(1)* addrspace(1)* %p |
| %cmp1 = call i1 @f(i32 addrspace(1)* %before) |
| call void @llvm.assume(i1 %cmp1) |
| %safepoint_token = tail call token (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @func, i32 0, i32 0, i32 0, i32 0, i32 addrspace(1)* addrspace(1)* %p) |
| %pnew = call i32 addrspace(1)* addrspace(1)* @llvm.experimental.gc.relocate.p1p1i32(token %safepoint_token, i32 7, i32 7) |
| %after = load i32 addrspace(1)*, i32 addrspace(1)* addrspace(1)* %pnew |
| %cmp2 = call i1 @f(i32 addrspace(1)* %after) |
| ret i1 %cmp2 |
| |
| ; CHECK-OPT-LABEL: test_load_forward |
| ; CHECK-OPT: ret i1 %cmp2 |
| ; CHECK-LLC-LABEL: test_load_forward |
| ; CHECK-LLC: callq f |
| } |
| |
| ;; Same as above, but forwarding from a store |
| define i1 @test_store_forward(i32 addrspace(1)* addrspace(1)* %p, |
| i32 addrspace(1)* %v) gc "statepoint-example" { |
| entry: |
| %cmp1 = call i1 @f(i32 addrspace(1)* %v) |
| call void @llvm.assume(i1 %cmp1) |
| store i32 addrspace(1)* %v, i32 addrspace(1)* addrspace(1)* %p |
| %safepoint_token = tail call token (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @func, i32 0, i32 0, i32 0, i32 0, i32 addrspace(1)* addrspace(1)* %p) |
| %pnew = call i32 addrspace(1)* addrspace(1)* @llvm.experimental.gc.relocate.p1p1i32(token %safepoint_token, i32 7, i32 7) |
| %after = load i32 addrspace(1)*, i32 addrspace(1)* addrspace(1)* %pnew |
| %cmp2 = call i1 @f(i32 addrspace(1)* %after) |
| ret i1 %cmp2 |
| |
| ; CHECK-OPT-LABEL: test_store_forward |
| ; CHECK-OPT: ret i1 %cmp2 |
| ; CHECK-LLC-LABEL: test_store_forward |
| ; CHECK-LLC: callq f |
| } |
| |
| ; A predicate on the pointer which is not simply null, but whose value |
| ; would be known unchanged if the pointer value could be forwarded. |
| ; The implementation of such a function could inspect the integral value |
| ; of the pointer and is thus not safe to reuse after a statepoint. |
| declare i1 @f(i32 addrspace(1)* %v) readnone |
| |
| ; This is a variant of the test_load_forward test which is intended to |
| ; highlight the fact that a gc pointer can be stored in part of the heap |
| ; that is not itself GC managed. The GC may have an external mechanism |
| ; to know about and update that value at a safepoint. Note that the |
| ; statepoint does not provide the collector with this root. |
| define i1 @test_load_forward_nongc_heap(i32 addrspace(1)** %p) gc "statepoint-example" { |
| entry: |
| %before = load i32 addrspace(1)*, i32 addrspace(1)** %p |
| %cmp1 = call i1 @f(i32 addrspace(1)* %before) |
| call void @llvm.assume(i1 %cmp1) |
| call token (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @func, i32 0, i32 0, i32 0, i32 0) |
| %after = load i32 addrspace(1)*, i32 addrspace(1)** %p |
| %cmp2 = call i1 @f(i32 addrspace(1)* %after) |
| ret i1 %cmp2 |
| |
| ; CHECK-OPT-LABEL: test_load_forward_nongc_heap |
| ; CHECK-OPT: ret i1 %cmp2 |
| ; CHECK-LLC-LABEL: test_load_forward_nongc_heap |
| ; CHECK-LLC: callq f |
| } |
| |
| ;; Same as above, but forwarding from a store |
| define i1 @test_store_forward_nongc_heap(i32 addrspace(1)** %p, |
| i32 addrspace(1)* %v) gc "statepoint-example" { |
| entry: |
| %cmp1 = call i1 @f(i32 addrspace(1)* %v) |
| call void @llvm.assume(i1 %cmp1) |
| store i32 addrspace(1)* %v, i32 addrspace(1)** %p |
| call token (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @func, i32 0, i32 0, i32 0, i32 0) |
| %after = load i32 addrspace(1)*, i32 addrspace(1)** %p |
| %cmp2 = call i1 @f(i32 addrspace(1)* %after) |
| ret i1 %cmp2 |
| |
| ; CHECK-OPT-LABEL: test_store_forward_nongc_heap |
| ; CHECK-OPT: ret i1 %cmp2 |
| ; CHECK-LLC-LABEL: test_store_forward_nongc_heap |
| ; CHECK-LLC: callq f |
| } |
| |
| declare void @llvm.assume(i1) |
| declare token @llvm.experimental.gc.statepoint.p0f_isVoidf(i64, i32, void ()*, i32, i32, ...) |
| declare i32 addrspace(1)* addrspace(1)* @llvm.experimental.gc.relocate.p1p1i32(token, i32, i32) #3 |