Add declarations of explicit specializations and instantiations. (#430)

Currently, code that uses the specializations in question will
accidentally and erroneously specialize the primary template. The
reason this appears to "work" is a pure accident due to the way the
linker currently works. The code violates the one-definition-rule,
and all programs depending on it are ill-formed, no diagnostic
required (i.e. running all such programs has undefined behaviour).

Additionally, declaring explicit instantiations is also good
practice, since it declares intent and prevents accidental later
explicit specializations (it would be an error to declare those
after the extern declaration of the explicit instantiation had been
seen).

Explicit specializations and instantiations are declared in .hpp
files near the respective template.

(Found by @tkoeppe by compiling with clang -Wundefined-func-template.)

src/cpu/cpu_reducer.hpp

@@ -198,6 +198,10 @@ struct cpu_reducer_t {
     void reduce_nolock(int ithr, data_t *dst);
 };
 
+// Explicit instantiations in cpu_reducer.cpp.
+extern template struct cpu_reducer_t<data_type::f32>;
+extern template struct cpu_reducer_t<data_type::s32>;
+
 template <impl::data_type_t data_type>
 struct cpu_reducer_2d_t {
     typedef typename prec_traits<data_type>::type data_t;
@@ -254,6 +258,10 @@ struct cpu_reducer_2d_t {
     void reduce_nolock(int ithr, data_t *dst);
 };
 
+// Explicit instantiations in cpu_reducer.cpp.
+extern template struct cpu_reducer_2d_t<data_type::f32>;
+extern template struct cpu_reducer_2d_t<data_type::s32>;
+
 /** simple 1d accumulator: y[:] += x[:] */
 template <impl::data_type_t data_type>
 struct cpu_accumulator_1d_t {
@@ -266,6 +274,10 @@ struct cpu_accumulator_1d_t {
     reducer_2d_driver_t<data_type> *drv_;
 };
 
+// Explicit instantiations in cpu_reducer.cpp.
+extern template struct cpu_accumulator_1d_t<data_type::f32>;
+extern template struct cpu_accumulator_1d_t<data_type::s32>;
+
 }
 }
 }

src/cpu/gemm/gemm.hpp

@@ -36,6 +36,18 @@ void ref_gemm(const char *transa, const char *transb, const int *M,
         const int *N, const int *K, const data_t *alpha, const data_t *A,
         const int *lda, const data_t *B, const int *ldb, const data_t *beta,
         data_t *C, const int *ldc, const data_t *bias);
+
+// Explicit instantiations in ref_gemm.cpp.
+extern template
+void ref_gemm<float>(const char *transa_, const char *transb_,
+        const int *M_, const int *N_, const int *K_, const float *alpha_,
+        const float *A, const int *lda_, const float *B, const int *ldb_,
+        const float *beta_, float *C, const int *ldc_, const float *bias);
+extern template
+void ref_gemm<double>(const char *transa_, const char *transb_,
+        const int *M_, const int *N_, const int *K_, const double *alpha_,
+        const double *A, const int *lda_, const double *B, const int *ldb_,
+        const double *beta_, double *C, const int *ldc_, const double *bias);
 #ifdef USE_CBLAS
 #define GEMM_IMPL_STR "gemm:blas"
 #else

src/cpu/gemm/gemm_utils.hpp

@@ -51,6 +51,14 @@ template <typename data_type>
 void sum_two_matrices(
         int m, int n, data_type *p_src, int ld_src, data_type *p_dst, int ld_dst);
 
+// Explicit instantiations are provided in gemm_utils.cpp.
+extern template
+void sum_two_matrices<float>(
+        int m, int n, float *p_src, int ld_src, float *p_dst, int ld_dst);
+extern template
+void sum_two_matrices<double>(
+        int m, int n, double *p_src, int ld_src, double *p_dst, int ld_dst);
+
 void calc_nthr_nocopy_avx512_common(int m,
         int n, int k, int nthrs, int *nthrs_m, int *nthrs_n, int *nthrs_k,
         int *BM, int *BN, int *BK);

src/cpu/jit_avx512_common_convolution_winograd.hpp

@@ -203,6 +203,20 @@ struct _jit_avx512_common_convolution_winograd_t {
         const primitive_attr_t *attr_;
 };
 
+// Explicit instantiations in jit_avx512_common_convolution_winograd.cpp.
+extern template void
+_jit_avx512_common_convolution_winograd_t<true>::_execute_data_W_S_G_D(
+        float *, float *, float *, float *);
+extern template void
+_jit_avx512_common_convolution_winograd_t<false>::_execute_data_W_S_G_D(
+        float *, float *, float *, float *);
+extern template void
+_jit_avx512_common_convolution_winograd_t<true>::_execute_data_W_SGD(
+        float *, float *, float *, float *);
+extern template void
+_jit_avx512_common_convolution_winograd_t<false>::_execute_data_W_SGD(
+        float *, float *, float *, float *);
+
 template <bool with_relu>
 struct _jit_avx512_common_convolution_winograd_fwd_t
      : _jit_avx512_common_convolution_winograd_t<true>

src/cpu/jit_uni_dw_conv_kernel_f32.hpp

@@ -300,6 +300,12 @@ struct jit_uni_dw_conv_bwd_weights_kernel_f32 : public jit_generator {
 
     void generate();
 };
+
+// Explicit instantiations in jit_uni_dw_conv_kernel_f32.cpp.
+extern template struct jit_uni_dw_conv_bwd_weights_kernel_f32<avx512_common>;
+extern template struct jit_uni_dw_conv_bwd_weights_kernel_f32<avx2>;
+extern template struct jit_uni_dw_conv_bwd_weights_kernel_f32<sse42>;
+
 }
 }
 }

src/cpu/jit_uni_eltwise.hpp

@@ -29,6 +29,11 @@ namespace mkldnn {
 namespace impl {
 namespace cpu {
 
+// Explicit instantiations are in jit_uni_eltwise.cpp.
+extern template struct jit_uni_eltwise_injector_f32<avx512_common>;
+extern template struct jit_uni_eltwise_injector_f32<avx2>;
+extern template struct jit_uni_eltwise_injector_f32<sse42>;
+
 struct jit_uni_eltwise_kernel_f32;
 
 template <cpu_isa_t isa>

src/cpu/jit_uni_lrn_kernel_f32.hpp

@@ -173,6 +173,60 @@ struct jit_uni_lrn_bwd_kernel_f32 : public jit_generator {
     void(*ker)(jit_args_bwd_t *);
 };
 
+// Explicit specializations and instantiations in jit_uni_lrn_kernel_f32.cpp.
+template <>
+jit_uni_lrn_fwd_kernel_f32<avx2>::jit_uni_lrn_fwd_kernel_f32(
+    const struct nchw8c_across &J, float A, float K, prop_kind_t pk,
+    void *code_ptr, size_t code_size);
+template <>
+jit_uni_lrn_fwd_kernel_f32<sse42>::jit_uni_lrn_fwd_kernel_f32(
+    const struct nchw8c_across &J, float A, float K, prop_kind_t pk,
+    void *code_ptr, size_t code_size);
+template <>
+jit_uni_lrn_fwd_kernel_f32<avx2>::jit_uni_lrn_fwd_kernel_f32(
+    const struct nhwc_across &J, float A, float K, prop_kind_t pk,
+    void *code_ptr, size_t code_size);
+template <>
+jit_uni_lrn_fwd_kernel_f32<sse42>::jit_uni_lrn_fwd_kernel_f32(
+    const struct nhwc_across &J, float A, float K, prop_kind_t pk,
+    void *code_ptr, size_t code_size);
+template <>
+void jit_uni_lrn_fwd_kernel_f32<sse42>::nchw_body(
+    int tail, int HW, prop_kind_t pk, Xbyak::Ymm ymask, Xbyak::Ymm ya,
+    Xbyak::Ymm yb, Xbyak::Ymm yc, Xbyak::Ymm yd, Xbyak::Ymm ye,
+    Xbyak::Ymm ysum);
+template <>
+void jit_uni_lrn_fwd_kernel_f32<avx2>::nchw_body(
+    int tail, int HW, prop_kind_t pk, Xbyak::Ymm ymask, Xbyak::Ymm ya,
+    Xbyak::Ymm yb, Xbyak::Ymm yc, Xbyak::Ymm yd, Xbyak::Ymm ye,
+    Xbyak::Ymm ysum);
+template <>
+void jit_uni_lrn_fwd_kernel_f32<avx2>::nchw_tail_sse42(
+    int tail, Xbyak::Reg64 reg_dst, Xbyak::Xmm xtail_lo, Xbyak::Xmm xtail_hi);
+template <>
+void jit_uni_lrn_fwd_kernel_f32<sse42>::nchw_tail_sse42(
+    int tail, Xbyak::Reg64 reg_dst, Xbyak::Xmm xtail_lo, Xbyak::Xmm xtail_hi);
+template <>
+void jit_uni_lrn_fwd_kernel_f32<sse42>::nchw_body_sse42(
+    int tail, int HW, prop_kind_t pk, Xbyak::Xmm xmask_lo, Xbyak::Xmm xmask_hi,
+    Xbyak::Xmm xe_lo, Xbyak::Xmm xe_hi, Xbyak::Xmm xsum_lo, Xbyak::Xmm xsum_hi);
+template <>
+void jit_uni_lrn_fwd_kernel_f32<avx2>::nchw_body_sse42(
+    int tail, int HW, prop_kind_t pk, Xbyak::Xmm xmask_lo, Xbyak::Xmm xmask_hi,
+    Xbyak::Xmm xe_lo, Xbyak::Xmm xe_hi, Xbyak::Xmm xsum_lo, Xbyak::Xmm xsum_hi);
+template <>
+jit_uni_lrn_fwd_kernel_f32<avx2>::jit_uni_lrn_fwd_kernel_f32(
+    struct nchw_across J, float A, float K, prop_kind_t pk, void *code_ptr,
+    size_t code_size);
+template <>
+jit_uni_lrn_fwd_kernel_f32<sse42>::jit_uni_lrn_fwd_kernel_f32(
+    struct nchw_across J, float A, float K, prop_kind_t pk, void *code_ptr,
+    size_t code_size);
+
+extern template struct jit_uni_lrn_fwd_kernel_f32<sse42>;
+extern template struct jit_uni_lrn_fwd_kernel_f32<avx2>;
+extern template struct jit_uni_lrn_bwd_kernel_f32<avx2>;
+
 }
 }
 }

src/cpu/jit_uni_pool_kernel_f32.hpp

@@ -184,6 +184,11 @@ struct jit_uni_pool_kernel_f32: public jit_generator {
     }
 };
 
+// Explicit instantiations in jit_uni_pool_kernel_f32.cpp.
+extern template struct jit_uni_pool_kernel_f32<sse42>;
+extern template struct jit_uni_pool_kernel_f32<avx>;
+extern template struct jit_uni_pool_kernel_f32<avx512_common>;
+
 }
 }
 }