[sycl-post-link] Do not drop SYCL_EXTERNAL functions

llvm/test/tools/sycl-post-link/erase_used.ll

@@ -10,10 +10,12 @@ target triple = "spir64-unknown-unknown-sycldevice"
 ; CHECK-NOT: llvm.used
 @llvm.used = appending global [2 x i8*] [i8* bitcast (void ()* @foo to i8*), i8* bitcast (void ()* @bar to i8*)], section "llvm.metadata"
 
-define weak_odr spir_kernel void @foo() {
+define weak_odr spir_kernel void @foo() #0 {
   ret void
 }
 
-define weak_odr spir_kernel void @bar() {
+define weak_odr spir_kernel void @bar() #0 {
   ret void
 }
+
+attributes #0 = { "sycl-module-id"="a.cpp" }

llvm/test/tools/sycl-post-link/spec-constants/spec_const_and_split.ll

@@ -21,25 +21,27 @@
 
 declare dso_local spir_func zeroext i1 @_Z33__sycl_getScalarSpecConstantValueIbET_PKc(i8 addrspace(4)*)
 
-define dso_local spir_kernel void @KERNEL_AAA() {
+define dso_local spir_kernel void @KERNEL_AAA() #0 {
   %1 = call spir_func zeroext i1 @_Z33__sycl_getScalarSpecConstantValueIbET_PKc(i8 addrspace(4)* addrspacecast (i8* getelementptr inbounds ([10 x i8], [10 x i8]* @SCSymID, i64 0, i64 0) to i8 addrspace(4)*))
 ; CHECK-IR0: %{{[0-9]+}} = call i1 @_Z20__spirv_SpecConstantib(i32 1, i1 false)
   %2 = call spir_func zeroext i1 @_Z33__sycl_getScalarSpecConstantValueIbET_PKc(i8 addrspace(4)* addrspacecast (i8* getelementptr inbounds ([11 x i8], [11 x i8]* @SCSymID2, i64 0, i64 0) to i8 addrspace(4)*))
 ; CHECK-IR0: %{{[0-9]+}} = call i1 @_Z20__spirv_SpecConstantib(i32 0, i1 false)
   ret void
 }
 
-define dso_local spir_kernel void @KERNEL_BBB() {
+define dso_local spir_kernel void @KERNEL_BBB() #0 {
   %1 = call spir_func zeroext i1 @_Z33__sycl_getScalarSpecConstantValueIbET_PKc(i8 addrspace(4)* addrspacecast (i8* getelementptr inbounds ([10 x i8], [10 x i8]* @SCSymID, i64 0, i64 0) to i8 addrspace(4)*))
 ; CHECK-IR1: %{{[0-9]+}} = call i1 @_Z20__spirv_SpecConstantib(i32 0, i1 false)
   ret void
 }
 
-define dso_local spir_kernel void @KERNEL_CCC() {
+define dso_local spir_kernel void @KERNEL_CCC() #0 {
 ; CHECK-IR2: define{{.*}}spir_kernel void @KERNEL_CCC
   ret void
 }
 
+attributes #0 = { "sycl-module-id"="a.cpp" }
+
 ; CHECK-IR0: !sycl.specialization-constants = !{![[#MD0:]], ![[#MD1:]]}
 ; CHECK-IR0: ![[#MD0:]] = !{!"SpecConst2", i32 0, i32 0, i32 1}
 ; CHECK-IR0: ![[#MD1:]] = !{!"SpecConst", i32 1, i32 0, i32 1}

llvm/test/tools/sycl-post-link/sycl-external-funcs/drop-known-builtins.ll

@@ -0,0 +1,33 @@
+; RUN: sycl-post-link -ir-output-only -split=auto -S %s -o %t.ll
+; RUN: FileCheck %s -input-file=%t.ll
+
+; This test checks that known SPIRV and SYCL builtin functions
+; (that are also marked with SYCL_EXTRENAL) are not considered
+; as module entry points and thus are not added as entry to the
+; device binary symbol table. So, they can be dropped if
+; unreferenced.
+
+target datalayout = "e-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024"
+target triple = "spir64-unknown-linux-sycldevice"
+
+define dso_local spir_func void @_Z28__spirv_GlobalInvocationId_xv() #0 {
+  ret void
+}
+define dso_local spir_func void @_Z28__spXrv_GlobalInvocationId_xv() #0 {
+  ret void
+}
+
+define dso_local spir_func void @_Z33__sycl_getScalarSpecConstantValue() #0 {
+  ret void
+}
+define dso_local spir_func void @_Z33__sXcl_getScalarSpecConstantValue() #0 {
+  ret void
+}
+
+attributes #0 = { "sycl-module-id"="a.cpp" }
+
+; CHECK-NOT: define dso_local spir_func void @_Z28__spirv_GlobalInvocationId_xv()
+; CHECK-NOT: define dso_local spir_func void @_Z33__sycl_getScalarSpecConstantValue()
+
+; CHECK-DAG: define dso_local spir_func void @_Z28__spXrv_GlobalInvocationId_xv()
+; CHECK-DAG: define dso_local spir_func void @_Z33__sXcl_getScalarSpecConstantValue()

llvm/test/tools/sycl-post-link/sycl-external-funcs/drop-unref-funcs.ll

@@ -0,0 +1,21 @@
+; RUN: sycl-post-link -ir-output-only -split=auto -S %s -o %t.ll
+; RUN: FileCheck %s -input-file=%t.ll
+
+; This test checks that unreferenced functions without sycl-module-id
+; attribute are dropped from the module after splitting.
+
+target datalayout = "e-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024"
+target triple = "spir64-unknown-linux-sycldevice"
+
+define dso_local spir_func void @externalDeviceFunc() #0 {
+  ret void
+}
+
+define dso_local spir_func void @unreferencedFunc() {
+  ret void
+}
+
+attributes #0 = { "sycl-module-id"="a.cpp" }
+
+; CHECK: define dso_local spir_func void @externalDeviceFunc()
+; CHECK-NOT: define dso_local spir_func void @unreferencedFunc()

llvm/test/tools/sycl-post-link/sycl-external-funcs/keep-indirectly-ref-funcs.ll

@@ -0,0 +1,16 @@
+; RUN: sycl-post-link -ir-output-only -split=auto -S %s -o %t.ll
+; RUN: FileCheck %s -input-file=%t.ll
+
+; This test checks that indirectly referenced functions (with sycl-module-id
+; attribute) are not dropped from the module.
+
+target datalayout = "e-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024"
+target triple = "spir64-unknown-linux-sycldevice"
+
+define dso_local spir_func void @indRefDeviceFunc() #0 {
+  ret void
+}
+
+attributes #0 = { "sycl-module-id"="a.cpp" "referenced-indirectly"}
+
+; CHECK: define dso_local spir_func void @indRefDeviceFunc()

llvm/test/tools/sycl-post-link/sycl-external-funcs/split-and-lower-esimd.ll

@@ -0,0 +1,30 @@
+; RUN: sycl-post-link -split=auto -split-esimd -lower-esimd -O0 -S %s -o %t.table
+; RUN: FileCheck %s -input-file=%t_esimd_0.ll
+
+; This test checks that unreferenced functions with sycl-module-id
+; attribute are not dropped from the module and ESIMD lowering
+; happens for them as well.
+
+target datalayout = "e-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024"
+target triple = "spir64-unknown-linux-sycldevice"
+
+@__spirv_BuiltInGlobalInvocationId = external dso_local local_unnamed_addr addrspace(1) constant <3 x i64>, align 32
+
+define dso_local spir_func void @externalESIMDDeviceFunc() #0 !sycl_explicit_simd !0 {
+entry:
+  %0 = load <3 x i64>, <3 x i64> addrspace(4)* addrspacecast (<3 x i64> addrspace(1)* @__spirv_BuiltInGlobalInvocationId to <3 x i64> addrspace(4)*), align 32
+  %1 = extractelement <3 x i64> %0, i64 0
+  ret void
+}
+
+attributes #0 = { "sycl-module-id"="a.cpp" }
+
+!0 = !{}
+
+; CHECK: define dso_local spir_func void @externalESIMDDeviceFunc()
+; CHECK: entry:
+; CHECK:   call <3 x i32> @llvm.genx.local.id.v3i32()
+; CHECK:   call <3 x i32> @llvm.genx.local.size.v3i32()
+; CHECK:   call i32 @llvm.genx.group.id.x()
+; CHECK:   ret void
+; CHECK: }

llvm/test/tools/sycl-post-link/sycl-external-funcs/split-global.ll

@@ -0,0 +1,22 @@
+; RUN: sycl-post-link -ir-output-only -split=auto -S %s -o %t.ll
+; RUN: FileCheck %s -input-file=%t.ll
+
+; This test checks that unreferenced functions with sycl-module-id
+; attribute are not dropped from the module after splitting
+; in global mode.
+
+target datalayout = "e-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024"
+target triple = "spir64-unknown-linux-sycldevice"
+
+define dso_local spir_func void @externalDeviceFunc() #0 {
+  ret void
+}
+
+define dso_local spir_kernel void @kernel1() #0 {
+  ret void
+}
+
+attributes #0 = { "sycl-module-id"="a.cpp" }
+
+; CHECK-DAG: define dso_local spir_func void @externalDeviceFunc()
+; CHECK-DAG: define dso_local spir_kernel void @kernel1()

llvm/test/tools/sycl-post-link/sycl-external-funcs/split-per-kernel.ll

@@ -0,0 +1,28 @@
+; RUN: sycl-post-link -split=kernel -symbols -S %s -o %t.table
+; RUN: FileCheck %s -input-file=%t_0.ll --check-prefixes CHECK-IR1
+; RUN: FileCheck %s -input-file=%t_1.ll --check-prefixes CHECK-IR2
+; RUN: FileCheck %s -input-file=%t_0.sym --check-prefixes CHECK-SYM1
+; RUN: FileCheck %s -input-file=%t_1.sym --check-prefixes CHECK-SYM2
+
+; This test checks that unreferenced functions with sycl-module-id
+; attribute are not dropped from the module after splitting
+; in per-kernel mode.
+
+target datalayout = "e-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024"
+target triple = "spir64-unknown-linux-sycldevice"
+
+define dso_local spir_func void @externalDeviceFunc() #0 {
+  ret void
+}
+
+define dso_local spir_kernel void @kernel1() #0 {
+  ret void
+}
+
+attributes #0 = { "sycl-module-id"="a.cpp" }
+
+; CHECK-IR1: define dso_local spir_func void @externalDeviceFunc()
+; CHECK-IR2: define dso_local spir_kernel void @kernel1()
+
+; CHECK-SYM1: externalDeviceFunc
+; CHECK-SYM2: kernel1

llvm/test/tools/sycl-post-link/sycl-external-funcs/split-per-source1.ll

@@ -0,0 +1,29 @@
+; RUN: sycl-post-link -split=source -symbols -S %s -o %t.table
+; RUN: FileCheck %s -input-file=%t_0.ll --check-prefixes CHECK-IR1
+; RUN: FileCheck %s -input-file=%t_1.ll --check-prefixes CHECK-IR2
+; RUN: FileCheck %s -input-file=%t_0.sym --check-prefixes CHECK-SYM1
+; RUN: FileCheck %s -input-file=%t_1.sym --check-prefixes CHECK-SYM2
+
+; This test checks that unreferenced functions with sycl-module-id
+; attribute are not dropped from the module after splitting
+; in per-source mode.
+
+target datalayout = "e-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024"
+target triple = "spir64-unknown-linux-sycldevice"
+
+define dso_local spir_func void @externalDeviceFunc() #0 {
+  ret void
+}
+
+define dso_local spir_kernel void @kernel1() #1 {
+  ret void
+}
+
+attributes #0 = { "sycl-module-id"="a.cpp" }
+attributes #1 = { "sycl-module-id"="b.cpp" }
+
+; CHECK-IR1: define dso_local spir_func void @externalDeviceFunc()
+; CHECK-IR2: define dso_local spir_kernel void @kernel1()
+
+; CHECK-SYM1: externalDeviceFunc
+; CHECK-SYM2: kernel1

llvm/test/tools/sycl-post-link/sycl-external-funcs/split-per-source2.ll

@@ -0,0 +1,30 @@
+; RUN: sycl-post-link -split=source -symbols -S %s -o %t.table
+; RUN: FileCheck %s -input-file=%t_0.ll --check-prefixes CHECK-IR1
+; RUN: FileCheck %s -input-file=%t_1.ll --check-prefixes CHECK-IR2
+; RUN: FileCheck %s -input-file=%t_0.sym --check-prefixes CHECK-SYM1
+; RUN: FileCheck %s -input-file=%t_1.sym --check-prefixes CHECK-SYM2
+
+; This test checks that the definition of function externalDeviceFunc is
+; present in both resulting modules when per-source split is requested.
+
+target datalayout = "e-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024"
+target triple = "spir64-unknown-linux-sycldevice"
+
+define dso_local spir_func void @externalDeviceFunc() #0 {
+  ret void
+}
+
+define dso_local spir_kernel void @kernel1() #1 {
+  call void @externalDeviceFunc()
+  ret void
+}
+
+attributes #0 = { "sycl-module-id"="a.cpp" }
+attributes #1 = { "sycl-module-id"="b.cpp" }
+
+; CHECK-IR1: define dso_local spir_func void @externalDeviceFunc()
+; CHECK-IR2: define dso_local spir_func void @externalDeviceFunc()
+; CHECK-IR2: define dso_local spir_kernel void @kernel1()
+
+; CHECK-SYM1: externalDeviceFunc
+; CHECK-SYM2: kernel1

llvm/test/tools/sycl-post-link/sym_but_no_split.ll

@@ -6,20 +6,22 @@
 ; RUN: FileCheck %s -input-file=%t.files.table --check-prefixes CHECK-TABLE
 ; RUN: FileCheck %s -input-file=%t.files_0.sym --match-full-lines --check-prefixes CHECK-SYM
 
-define dso_local spir_kernel void @KERNEL_AAA() {
+define dso_local spir_kernel void @KERNEL_AAA() #0 {
 ; CHECK-SYM-NOT: {{[a-zA-Z0-9._@]+}}
 ; CHECK-SYM: KERNEL_AAA
 entry:
   ret void
 }
 
-define dso_local spir_kernel void @KERNEL_BBB() {
+define dso_local spir_kernel void @KERNEL_BBB() #0 {
 ; CHECK-SYM-NEXT: KERNEL_BBB
 ; CHECK-SYM-EMPTY:
 entry:
   ret void
 }
 
+attributes #0 = { "sycl-module-id"="a.cpp" }
+
 ; CHECK-TABLE: [Code|Properties|Symbols]
 ; CHECK-TABLE-NEXT: {{.*}}files_0.sym
 ; CHECK-TABLE-EMPTY: