Merge pull request #18910 from arjunroy/slice_eq_static

Added slice equality when static fastpath.

BUILD

@@ -997,6 +997,7 @@ grpc_cc_library(
         "src/core/lib/slice/slice_hash_table.h",
         "src/core/lib/slice/slice_internal.h",
         "src/core/lib/slice/slice_string_helpers.h",
+        "src/core/lib/slice/slice_utils.h",
         "src/core/lib/slice/slice_weak_hash_table.h",
         "src/core/lib/surface/api_trace.h",
         "src/core/lib/surface/call.h",

BUILD.gn

@@ -739,6 +739,7 @@ config("grpc_config") {
         "src/core/lib/slice/slice_internal.h",
         "src/core/lib/slice/slice_string_helpers.cc",
         "src/core/lib/slice/slice_string_helpers.h",
+        "src/core/lib/slice/slice_utils.h",
         "src/core/lib/slice/slice_weak_hash_table.h",
         "src/core/lib/surface/api_trace.cc",
         "src/core/lib/surface/api_trace.h",
@@ -1283,6 +1284,7 @@ config("grpc_config") {
         "src/core/lib/slice/slice_hash_table.h",
         "src/core/lib/slice/slice_internal.h",
         "src/core/lib/slice/slice_string_helpers.h",
+        "src/core/lib/slice/slice_utils.h",
         "src/core/lib/slice/slice_weak_hash_table.h",
         "src/core/lib/surface/api_trace.h",
         "src/core/lib/surface/call.h",

build.yaml

@@ -525,6 +525,7 @@ filegroups:
   - src/core/lib/slice/slice_hash_table.h
   - src/core/lib/slice/slice_internal.h
   - src/core/lib/slice/slice_string_helpers.h
+  - src/core/lib/slice/slice_utils.h
   - src/core/lib/slice/slice_weak_hash_table.h
   - src/core/lib/surface/api_trace.h
   - src/core/lib/surface/call.h

gRPC-C++.podspec

@@ -518,6 +518,7 @@ Pod::Spec.new do |s|
                       'src/core/lib/slice/slice_hash_table.h',
                       'src/core/lib/slice/slice_internal.h',
                       'src/core/lib/slice/slice_string_helpers.h',
+                      'src/core/lib/slice/slice_utils.h',
                       'src/core/lib/slice/slice_weak_hash_table.h',
                       'src/core/lib/surface/api_trace.h',
                       'src/core/lib/surface/call.h',
@@ -721,6 +722,7 @@ Pod::Spec.new do |s|
                               'src/core/lib/slice/slice_hash_table.h',
                               'src/core/lib/slice/slice_internal.h',
                               'src/core/lib/slice/slice_string_helpers.h',
+                              'src/core/lib/slice/slice_utils.h',
                               'src/core/lib/slice/slice_weak_hash_table.h',
                               'src/core/lib/surface/api_trace.h',
                               'src/core/lib/surface/call.h',

gRPC-Core.podspec

@@ -494,6 +494,7 @@ Pod::Spec.new do |s|
                       'src/core/lib/slice/slice_hash_table.h',
                       'src/core/lib/slice/slice_internal.h',
                       'src/core/lib/slice/slice_string_helpers.h',
+                      'src/core/lib/slice/slice_utils.h',
                       'src/core/lib/slice/slice_weak_hash_table.h',
                       'src/core/lib/surface/api_trace.h',
                       'src/core/lib/surface/call.h',
@@ -1147,6 +1148,7 @@ Pod::Spec.new do |s|
                               'src/core/lib/slice/slice_hash_table.h',
                               'src/core/lib/slice/slice_internal.h',
                               'src/core/lib/slice/slice_string_helpers.h',
+                              'src/core/lib/slice/slice_utils.h',
                               'src/core/lib/slice/slice_weak_hash_table.h',
                               'src/core/lib/surface/api_trace.h',
                               'src/core/lib/surface/call.h',

grpc.gemspec

@@ -428,6 +428,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/slice/slice_hash_table.h )
   s.files += %w( src/core/lib/slice/slice_internal.h )
   s.files += %w( src/core/lib/slice/slice_string_helpers.h )
+  s.files += %w( src/core/lib/slice/slice_utils.h )
   s.files += %w( src/core/lib/slice/slice_weak_hash_table.h )
   s.files += %w( src/core/lib/surface/api_trace.h )
   s.files += %w( src/core/lib/surface/call.h )

package.xml

@@ -433,6 +433,7 @@
     <file baseinstalldir="/" name="src/core/lib/slice/slice_hash_table.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/slice/slice_internal.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/slice/slice_string_helpers.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/slice/slice_utils.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/slice/slice_weak_hash_table.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/surface/api_trace.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/surface/call.h" role="src" />

src/core/ext/transport/chttp2/transport/parsing.cc

@@ -28,6 +28,7 @@
 
 #include "src/core/lib/profiling/timers.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
+#include "src/core/lib/slice/slice_utils.h"
 #include "src/core/lib/transport/http2_errors.h"
 #include "src/core/lib/transport/static_metadata.h"
 #include "src/core/lib/transport/status_conversion.h"
@@ -410,53 +411,42 @@ static void on_initial_header(void* tp, grpc_mdelem md) {
     gpr_free(value);
   }
 
-  if (GRPC_MDELEM_STORAGE(md) == GRPC_MDELEM_STORAGE_STATIC) {
+  // If md.payload == GRPC_MDELEM_GRPC_STATUS_1 or GRPC_MDELEM_GRPC_STATUS_2,
-    // We don't use grpc_mdelem_eq here to avoid executing additional
+  // then we have seen an error. In fact, if it is a GRPC_STATUS and it's
-    // instructions. The reasoning is if the payload is not equal, we already
+  // not equal to GRPC_MDELEM_GRPC_STATUS_0, then we have seen an error.
-    // know that the metadata elements are not equal because the md is
+  if (grpc_slice_eq_static_interned(GRPC_MDKEY(md), GRPC_MDSTR_GRPC_STATUS) &&
-    // confirmed to be static. If we had used grpc_mdelem_eq here, then if the
+      !grpc_mdelem_static_value_eq(md, GRPC_MDELEM_GRPC_STATUS_0)) {
-    // payloads are not equal, grpc_mdelem_eq executes more instructions to
+    /* TODO(ctiller): check for a status like " 0" */
-    // determine if they're equal or not.
+    s->seen_error = true;
-    if (md.payload == GRPC_MDELEM_GRPC_STATUS_1.payload ||
+  } else if (grpc_slice_eq_static_interned(GRPC_MDKEY(md),
-        md.payload == GRPC_MDELEM_GRPC_STATUS_2.payload) {
+                                           GRPC_MDSTR_GRPC_TIMEOUT)) {
-      s->seen_error = true;
+    grpc_millis* cached_timeout =
-    }
+        static_cast<grpc_millis*>(grpc_mdelem_get_user_data(md, free_timeout));
-  } else {
+    grpc_millis timeout;
-    if (grpc_slice_eq(GRPC_MDKEY(md), GRPC_MDSTR_GRPC_STATUS) &&
+    if (cached_timeout != nullptr) {
-        !grpc_mdelem_eq(md, GRPC_MDELEM_GRPC_STATUS_0)) {
+      timeout = *cached_timeout;
-      /* TODO(ctiller): check for a status like " 0" */
+    } else {
-      s->seen_error = true;
+      if (GPR_UNLIKELY(
-    }
+              !grpc_http2_decode_timeout(GRPC_MDVALUE(md), &timeout))) {
-
+        char* val = grpc_slice_to_c_string(GRPC_MDVALUE(md));
-    if (grpc_slice_eq(GRPC_MDKEY(md), GRPC_MDSTR_GRPC_TIMEOUT)) {
+        gpr_log(GPR_ERROR, "Ignoring bad timeout value '%s'", val);
-      grpc_millis* cached_timeout = static_cast<grpc_millis*>(
+        gpr_free(val);
-          grpc_mdelem_get_user_data(md, free_timeout));
+        timeout = GRPC_MILLIS_INF_FUTURE;
-      grpc_millis timeout;
-      if (cached_timeout != nullptr) {
-        timeout = *cached_timeout;
-      } else {
-        if (GPR_UNLIKELY(
-                !grpc_http2_decode_timeout(GRPC_MDVALUE(md), &timeout))) {
-          char* val = grpc_slice_to_c_string(GRPC_MDVALUE(md));
-          gpr_log(GPR_ERROR, "Ignoring bad timeout value '%s'", val);
-          gpr_free(val);
-          timeout = GRPC_MILLIS_INF_FUTURE;
-        }
-        if (GRPC_MDELEM_IS_INTERNED(md)) {
-          /* store the result */
-          cached_timeout =
-              static_cast<grpc_millis*>(gpr_malloc(sizeof(grpc_millis)));
-          *cached_timeout = timeout;
-          grpc_mdelem_set_user_data(md, free_timeout, cached_timeout);
-        }
       }
-      if (timeout != GRPC_MILLIS_INF_FUTURE) {
+      if (GRPC_MDELEM_IS_INTERNED(md)) {
-        grpc_chttp2_incoming_metadata_buffer_set_deadline(
+        /* store the result */
-            &s->metadata_buffer[0], grpc_core::ExecCtx::Get()->Now() + timeout);
+        cached_timeout =
+            static_cast<grpc_millis*>(gpr_malloc(sizeof(grpc_millis)));
+        *cached_timeout = timeout;
+        grpc_mdelem_set_user_data(md, free_timeout, cached_timeout);
       }
-      GRPC_MDELEM_UNREF(md);
-      return;
     }
+    if (timeout != GRPC_MILLIS_INF_FUTURE) {
+      grpc_chttp2_incoming_metadata_buffer_set_deadline(
+          &s->metadata_buffer[0], grpc_core::ExecCtx::Get()->Now() + timeout);
+    }
+    GRPC_MDELEM_UNREF(md);
+    return;
   }
 
   const size_t new_size = s->metadata_buffer[0].size + GRPC_MDELEM_LENGTH(md);
@@ -506,19 +496,11 @@ static void on_trailing_header(void* tp, grpc_mdelem md) {
     gpr_free(value);
   }
 
-  if (GRPC_MDELEM_STORAGE(md) == GRPC_MDELEM_STORAGE_STATIC) {
+  // If md.payload == GRPC_MDELEM_GRPC_STATUS_1 or GRPC_MDELEM_GRPC_STATUS_2,
-    // We don't use grpc_mdelem_eq here to avoid executing additional
+  // then we have seen an error. In fact, if it is a GRPC_STATUS and it's
-    // instructions. The reasoning is if the payload is not equal, we already
+  // not equal to GRPC_MDELEM_GRPC_STATUS_0, then we have seen an error.
-    // know that the metadata elements are not equal because the md is
+  if (grpc_slice_eq_static_interned(GRPC_MDKEY(md), GRPC_MDSTR_GRPC_STATUS) &&
-    // confirmed to be static. If we had used grpc_mdelem_eq here, then if the
+      !grpc_mdelem_static_value_eq(md, GRPC_MDELEM_GRPC_STATUS_0)) {
-    // payloads are not equal, grpc_mdelem_eq executes more instructions to
-    // determine if they're equal or not.
-    if (md.payload == GRPC_MDELEM_GRPC_STATUS_1.payload ||
-        md.payload == GRPC_MDELEM_GRPC_STATUS_2.payload) {
-      s->seen_error = true;
-    }
-  } else if (grpc_slice_eq(GRPC_MDKEY(md), GRPC_MDSTR_GRPC_STATUS) &&
-             !grpc_mdelem_eq(md, GRPC_MDELEM_GRPC_STATUS_0)) {
     /* TODO(ctiller): check for a status like " 0" */
     s->seen_error = true;
   }

src/core/ext/transport/cronet/transport/cronet_transport.cc

@@ -753,15 +753,16 @@ static void convert_metadata_to_cronet_headers(
     } else {
       value = grpc_slice_to_c_string(GRPC_MDVALUE(mdelem));
     }
-    if (grpc_slice_eq(GRPC_MDKEY(mdelem), GRPC_MDSTR_SCHEME) ||
+    if (grpc_slice_eq_static_interned(GRPC_MDKEY(mdelem), GRPC_MDSTR_SCHEME) ||
-        grpc_slice_eq(GRPC_MDKEY(mdelem), GRPC_MDSTR_AUTHORITY)) {
+        grpc_slice_eq_static_interned(GRPC_MDKEY(mdelem),
+                                      GRPC_MDSTR_AUTHORITY)) {
       /* Cronet populates these fields on its own */
       gpr_free(key);
       gpr_free(value);
       continue;
     }
-    if (grpc_slice_eq(GRPC_MDKEY(mdelem), GRPC_MDSTR_METHOD)) {
+    if (grpc_slice_eq_static_interned(GRPC_MDKEY(mdelem), GRPC_MDSTR_METHOD)) {
-      if (grpc_slice_eq(GRPC_MDVALUE(mdelem), GRPC_MDSTR_PUT)) {
+      if (grpc_slice_eq_static_interned(GRPC_MDVALUE(mdelem), GRPC_MDSTR_PUT)) {
         *method = "PUT";
       } else {
         /* POST method in default*/
@@ -771,7 +772,7 @@ static void convert_metadata_to_cronet_headers(
       gpr_free(value);
       continue;
     }
-    if (grpc_slice_eq(GRPC_MDKEY(mdelem), GRPC_MDSTR_PATH)) {
+    if (grpc_slice_eq_static_interned(GRPC_MDKEY(mdelem), GRPC_MDSTR_PATH)) {
       /* Create URL by appending :path value to the hostname */
       gpr_asprintf(pp_url, "https://%s%s", host, value);
       gpr_free(key);
@@ -803,7 +804,8 @@ static void parse_grpc_header(const uint8_t* data, int* length,
 
 static bool header_has_authority(grpc_linked_mdelem* head) {
   while (head != nullptr) {
-    if (grpc_slice_eq(GRPC_MDKEY(head->md), GRPC_MDSTR_AUTHORITY)) {
+    if (grpc_slice_eq_static_interned(GRPC_MDKEY(head->md),
+                                      GRPC_MDSTR_AUTHORITY)) {
       return true;
     }
     head = head->next;

src/core/lib/compression/compression.cc

@@ -26,6 +26,7 @@
 #include "src/core/lib/compression/algorithm_metadata.h"
 #include "src/core/lib/compression/compression_internal.h"
 #include "src/core/lib/gpr/useful.h"
+#include "src/core/lib/slice/slice_utils.h"
 #include "src/core/lib/surface/api_trace.h"
 #include "src/core/lib/transport/static_metadata.h"
 
@@ -42,16 +43,17 @@ int grpc_compression_algorithm_is_stream(grpc_compression_algorithm algorithm) {
 
 int grpc_compression_algorithm_parse(grpc_slice name,
                                      grpc_compression_algorithm* algorithm) {
-  if (grpc_slice_eq(name, GRPC_MDSTR_IDENTITY)) {
+  if (grpc_slice_eq_static_interned(name, GRPC_MDSTR_IDENTITY)) {
     *algorithm = GRPC_COMPRESS_NONE;
     return 1;
-  } else if (grpc_slice_eq(name, GRPC_MDSTR_DEFLATE)) {
+  } else if (grpc_slice_eq_static_interned(name, GRPC_MDSTR_DEFLATE)) {
     *algorithm = GRPC_COMPRESS_DEFLATE;
     return 1;
-  } else if (grpc_slice_eq(name, GRPC_MDSTR_GZIP)) {
+  } else if (grpc_slice_eq_static_interned(name, GRPC_MDSTR_GZIP)) {
     *algorithm = GRPC_COMPRESS_GZIP;
     return 1;
-  } else if (grpc_slice_eq(name, GRPC_MDSTR_STREAM_SLASH_GZIP)) {
+  } else if (grpc_slice_eq_static_interned(name,
+                                           GRPC_MDSTR_STREAM_SLASH_GZIP)) {
     *algorithm = GRPC_COMPRESS_STREAM_GZIP;
     return 1;
   } else {
@@ -148,10 +150,13 @@ grpc_slice grpc_compression_algorithm_slice(
 
 grpc_compression_algorithm grpc_compression_algorithm_from_slice(
     const grpc_slice& str) {
-  if (grpc_slice_eq(str, GRPC_MDSTR_IDENTITY)) return GRPC_COMPRESS_NONE;
+  if (grpc_slice_eq_static_interned(str, GRPC_MDSTR_IDENTITY))
-  if (grpc_slice_eq(str, GRPC_MDSTR_DEFLATE)) return GRPC_COMPRESS_DEFLATE;
+    return GRPC_COMPRESS_NONE;
-  if (grpc_slice_eq(str, GRPC_MDSTR_GZIP)) return GRPC_COMPRESS_GZIP;
+  if (grpc_slice_eq_static_interned(str, GRPC_MDSTR_DEFLATE))
-  if (grpc_slice_eq(str, GRPC_MDSTR_STREAM_SLASH_GZIP))
+    return GRPC_COMPRESS_DEFLATE;
+  if (grpc_slice_eq_static_interned(str, GRPC_MDSTR_GZIP))
+    return GRPC_COMPRESS_GZIP;
+  if (grpc_slice_eq_static_interned(str, GRPC_MDSTR_STREAM_SLASH_GZIP))
     return GRPC_COMPRESS_STREAM_GZIP;
   return GRPC_COMPRESS_ALGORITHMS_COUNT;
 }

src/core/lib/compression/compression_internal.cc

@@ -26,6 +26,7 @@
 #include "src/core/lib/compression/algorithm_metadata.h"
 #include "src/core/lib/compression/compression_internal.h"
 #include "src/core/lib/gpr/useful.h"
+#include "src/core/lib/slice/slice_utils.h"
 #include "src/core/lib/surface/api_trace.h"
 #include "src/core/lib/transport/static_metadata.h"
 
@@ -33,18 +34,21 @@
 
 grpc_message_compression_algorithm
 grpc_message_compression_algorithm_from_slice(const grpc_slice& str) {
-  if (grpc_slice_eq(str, GRPC_MDSTR_IDENTITY))
+  if (grpc_slice_eq_static_interned(str, GRPC_MDSTR_IDENTITY))
     return GRPC_MESSAGE_COMPRESS_NONE;
-  if (grpc_slice_eq(str, GRPC_MDSTR_DEFLATE))
+  if (grpc_slice_eq_static_interned(str, GRPC_MDSTR_DEFLATE))
     return GRPC_MESSAGE_COMPRESS_DEFLATE;
-  if (grpc_slice_eq(str, GRPC_MDSTR_GZIP)) return GRPC_MESSAGE_COMPRESS_GZIP;
+  if (grpc_slice_eq_static_interned(str, GRPC_MDSTR_GZIP))
+    return GRPC_MESSAGE_COMPRESS_GZIP;
   return GRPC_MESSAGE_COMPRESS_ALGORITHMS_COUNT;
 }
 
 grpc_stream_compression_algorithm grpc_stream_compression_algorithm_from_slice(
     const grpc_slice& str) {
-  if (grpc_slice_eq(str, GRPC_MDSTR_IDENTITY)) return GRPC_STREAM_COMPRESS_NONE;
+  if (grpc_slice_eq_static_interned(str, GRPC_MDSTR_IDENTITY))
-  if (grpc_slice_eq(str, GRPC_MDSTR_GZIP)) return GRPC_STREAM_COMPRESS_GZIP;
+    return GRPC_STREAM_COMPRESS_NONE;
+  if (grpc_slice_eq_static_interned(str, GRPC_MDSTR_GZIP))
+    return GRPC_STREAM_COMPRESS_GZIP;
   return GRPC_STREAM_COMPRESS_ALGORITHMS_COUNT;
 }
 
@@ -244,13 +248,13 @@ grpc_message_compression_algorithm grpc_message_compression_algorithm_for_level(
 
 int grpc_message_compression_algorithm_parse(
     grpc_slice value, grpc_message_compression_algorithm* algorithm) {
-  if (grpc_slice_eq(value, GRPC_MDSTR_IDENTITY)) {
+  if (grpc_slice_eq_static_interned(value, GRPC_MDSTR_IDENTITY)) {
     *algorithm = GRPC_MESSAGE_COMPRESS_NONE;
     return 1;
-  } else if (grpc_slice_eq(value, GRPC_MDSTR_DEFLATE)) {
+  } else if (grpc_slice_eq_static_interned(value, GRPC_MDSTR_DEFLATE)) {
     *algorithm = GRPC_MESSAGE_COMPRESS_DEFLATE;
     return 1;
-  } else if (grpc_slice_eq(value, GRPC_MDSTR_GZIP)) {
+  } else if (grpc_slice_eq_static_interned(value, GRPC_MDSTR_GZIP)) {
     *algorithm = GRPC_MESSAGE_COMPRESS_GZIP;
     return 1;
   } else {
@@ -263,10 +267,10 @@ int grpc_message_compression_algorithm_parse(
 
 int grpc_stream_compression_algorithm_parse(
     grpc_slice value, grpc_stream_compression_algorithm* algorithm) {
-  if (grpc_slice_eq(value, GRPC_MDSTR_IDENTITY)) {
+  if (grpc_slice_eq_static_interned(value, GRPC_MDSTR_IDENTITY)) {
     *algorithm = GRPC_STREAM_COMPRESS_NONE;
     return 1;
-  } else if (grpc_slice_eq(value, GRPC_MDSTR_GZIP)) {
+  } else if (grpc_slice_eq_static_interned(value, GRPC_MDSTR_GZIP)) {
     *algorithm = GRPC_STREAM_COMPRESS_GZIP;
     return 1;
   } else {

src/core/lib/compression/stream_compression.cc

@@ -22,6 +22,7 @@
 
 #include "src/core/lib/compression/stream_compression.h"
 #include "src/core/lib/compression/stream_compression_gzip.h"
+#include "src/core/lib/slice/slice_utils.h"
 
 extern const grpc_stream_compression_vtable
     grpc_stream_compression_identity_vtable;
@@ -65,11 +66,11 @@ void grpc_stream_compression_context_destroy(
 int grpc_stream_compression_method_parse(
     grpc_slice value, bool is_compress,
     grpc_stream_compression_method* method) {
-  if (grpc_slice_eq(value, GRPC_MDSTR_IDENTITY)) {
+  if (grpc_slice_eq_static_interned(value, GRPC_MDSTR_IDENTITY)) {
     *method = is_compress ? GRPC_STREAM_COMPRESSION_IDENTITY_COMPRESS
                           : GRPC_STREAM_COMPRESSION_IDENTITY_DECOMPRESS;
     return 1;
-  } else if (grpc_slice_eq(value, GRPC_MDSTR_GZIP)) {
+  } else if (grpc_slice_eq_static_interned(value, GRPC_MDSTR_GZIP)) {
     *method = is_compress ? GRPC_STREAM_COMPRESSION_GZIP_COMPRESS
                           : GRPC_STREAM_COMPRESSION_GZIP_DECOMPRESS;
     return 1;

src/core/lib/slice/slice.cc

@@ -410,6 +410,31 @@ int grpc_slice_eq(grpc_slice a, grpc_slice b) {
   return grpc_slice_default_eq_impl(a, b);
 }
 
+int grpc_slice_differs_refcounted(const grpc_slice& a,
+                                  const grpc_slice& b_not_inline) {
+  size_t a_len;
+  const uint8_t* a_ptr;
+  if (a.refcount) {
+    a_len = a.data.refcounted.length;
+    a_ptr = a.data.refcounted.bytes;
+  } else {
+    a_len = a.data.inlined.length;
+    a_ptr = &a.data.inlined.bytes[0];
+  }
+  if (a_len != b_not_inline.data.refcounted.length) {
+    return true;
+  }
+  if (a_len == 0) {
+    return false;
+  }
+  // This check *must* occur after the a_len == 0 check
+  // to retain compatibility with grpc_slice_eq.
+  if (a_ptr == nullptr) {
+    return true;
+  }
+  return memcmp(a_ptr, b_not_inline.data.refcounted.bytes, a_len);
+}
+
 int grpc_slice_cmp(grpc_slice a, grpc_slice b) {
   int d = static_cast<int>(GRPC_SLICE_LENGTH(a) - GRPC_SLICE_LENGTH(b));
   if (d != 0) return d;

src/core/lib/slice/slice_intern.cc

@@ -19,6 +19,7 @@
 #include <grpc/support/port_platform.h>
 
 #include "src/core/lib/slice/slice_internal.h"
+#include "src/core/lib/slice/slice_utils.h"
 
 #include <inttypes.h>
 #include <string.h>
@@ -143,7 +144,8 @@ grpc_slice grpc_slice_maybe_static_intern(grpc_slice slice,
     static_metadata_hash_ent ent =
         static_metadata_hash[(hash + i) % GPR_ARRAY_SIZE(static_metadata_hash)];
     if (ent.hash == hash && ent.idx < GRPC_STATIC_MDSTR_COUNT &&
-        grpc_slice_eq(grpc_static_slice_table[ent.idx], slice)) {
+        grpc_slice_eq_static_interned(slice,
+                                      grpc_static_slice_table[ent.idx])) {
       *returned_slice_is_different = true;
       return grpc_static_slice_table[ent.idx];
     }
@@ -170,7 +172,8 @@ grpc_slice grpc_slice_intern(grpc_slice slice) {
     static_metadata_hash_ent ent =
         static_metadata_hash[(hash + i) % GPR_ARRAY_SIZE(static_metadata_hash)];
     if (ent.hash == hash && ent.idx < GRPC_STATIC_MDSTR_COUNT &&
-        grpc_slice_eq(grpc_static_slice_table[ent.idx], slice)) {
+        grpc_slice_eq_static_interned(slice,
+                                      grpc_static_slice_table[ent.idx])) {
       return grpc_static_slice_table[ent.idx];
     }
   }
@@ -183,7 +186,8 @@ grpc_slice grpc_slice_intern(grpc_slice slice) {
   /* search for an existing string */
   size_t idx = TABLE_IDX(hash, shard->capacity);
   for (s = shard->strs[idx]; s; s = s->bucket_next) {
-    if (s->hash == hash && grpc_slice_eq(slice, materialize(s))) {
+    if (s->hash == hash &&
+        grpc_slice_eq_static_interned(slice, materialize(s))) {
       if (s->refcnt.RefIfNonZero()) {
         gpr_mu_unlock(&shard->mu);
         return materialize(s);

src/core/lib/slice/slice_utils.h

@@ -0,0 +1,50 @@
+/*
+ *
+ * Copyright 2019 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_SLICE_SLICE_UTILS_H
+#define GRPC_CORE_LIB_SLICE_SLICE_UTILS_H
+
+#include <grpc/support/port_platform.h>
+
+#include <grpc/slice.h>
+
+// When we compare two slices, and we know the latter is not inlined, we can
+// short circuit our comparison operator. We specifically use differs()
+// semantics instead of equals() semantics due to more favourable code
+// generation when using differs(). Specifically, we may use the output of
+// grpc_slice_differs_refcounted for control flow. If we use differs()
+// semantics, we end with a tailcall to memcmp(). If we use equals() semantics,
+// we need to invert the result that memcmp provides us, which costs several
+// instructions to do so. If we're using the result for control flow (i.e.
+// branching based on the output) then we're just performing the extra
+// operations to invert the result pointlessly. Concretely, we save 6 ops on
+// x86-64/clang with differs().
+int grpc_slice_differs_refcounted(const grpc_slice& a,
+                                  const grpc_slice& b_not_inline);
+// When we compare two slices, and we *know* that one of them is static or
+// interned, we can short circuit our slice equality function. The second slice
+// here must be static or interned; slice a can be any slice, inlined or not.
+inline bool grpc_slice_eq_static_interned(const grpc_slice& a,
+                                          const grpc_slice& b_static_interned) {
+  if (a.refcount == b_static_interned.refcount) {
+    return true;
+  }
+  return !grpc_slice_differs_refcounted(a, b_static_interned);
+}
+
+#endif /* GRPC_CORE_LIB_SLICE_SLICE_UTILS_H */

src/core/lib/surface/call.cc

@@ -42,8 +42,8 @@
 #include "src/core/lib/gprpp/ref_counted.h"
 #include "src/core/lib/iomgr/timer.h"
 #include "src/core/lib/profiling/timers.h"
-#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
+#include "src/core/lib/slice/slice_utils.h"
 #include "src/core/lib/surface/api_trace.h"
 #include "src/core/lib/surface/call.h"
 #include "src/core/lib/surface/call_test_only.h"
@@ -349,8 +349,8 @@ grpc_error* grpc_call_create(const grpc_call_create_args* args,
                MAX_SEND_EXTRA_METADATA_COUNT);
     for (size_t i = 0; i < args->add_initial_metadata_count; i++) {
       call->send_extra_metadata[i].md = args->add_initial_metadata[i];
-      if (grpc_slice_eq(GRPC_MDKEY(args->add_initial_metadata[i]),
+      if (grpc_slice_eq_static_interned(
-                        GRPC_MDSTR_PATH)) {
+              GRPC_MDKEY(args->add_initial_metadata[i]), GRPC_MDSTR_PATH)) {
         path = grpc_slice_ref_internal(
             GRPC_MDVALUE(args->add_initial_metadata[i]));
       }

src/core/lib/transport/metadata.h

@@ -30,6 +30,7 @@
 #include "src/core/lib/gpr/useful.h"
 #include "src/core/lib/gprpp/atomic.h"
 #include "src/core/lib/gprpp/sync.h"
+#include "src/core/lib/slice/slice_utils.h"
 
 extern grpc_core::DebugOnlyTraceFlag grpc_trace_metadata;
 
@@ -138,7 +139,7 @@ bool grpc_mdelem_eq(grpc_mdelem a, grpc_mdelem b);
  * grpc_mdelem_eq and remove unnecessary checks. */
 inline bool grpc_mdelem_static_value_eq(grpc_mdelem a, grpc_mdelem b_static) {
   if (a.payload == b_static.payload) return true;
-  return grpc_slice_eq(GRPC_MDVALUE(a), GRPC_MDVALUE(b_static));
+  return grpc_slice_eq_static_interned(GRPC_MDVALUE(a), GRPC_MDVALUE(b_static));
 }
 
 /* Mutator and accessor for grpc_mdelem user data. The destructor function

src/core/lib/transport/static_metadata.cc

@@ -384,9 +384,9 @@ static const uint8_t elem_idxs[] = {
     52, 53, 54, 76,  69, 55,  56,  70, 58,  78,  80, 81, 82, 83, 59, 64,
     60, 75, 72, 255, 85, 255, 255, 68, 255, 255, 0};
 
-grpc_mdelem grpc_static_mdelem_for_static_strings(int a, int b) {
+grpc_mdelem grpc_static_mdelem_for_static_strings(intptr_t a, intptr_t b) {
   if (a == -1 || b == -1) return GRPC_MDNULL;
-  uint32_t k = (uint32_t)(a * 107 + b);
+  uint32_t k = static_cast<uint32_t>(a * 107 + b);
   uint32_t h = elems_phash(k);
   return h < GPR_ARRAY_SIZE(elem_keys) && elem_keys[h] == k &&
                  elem_idxs[h] != 255

src/core/lib/transport/static_metadata.h

@@ -29,6 +29,8 @@
 
 #include <grpc/support/port_platform.h>
 
+#include <cstdint>
+
 #include "src/core/lib/transport/metadata.h"
 
 #define GRPC_STATIC_MDSTR_COUNT 107
@@ -263,7 +265,8 @@ extern grpc_slice_refcount
    (slice).refcount->GetType() == grpc_slice_refcount::Type::STATIC)
 
 #define GRPC_STATIC_METADATA_INDEX(static_slice) \
-  ((int)((static_slice).refcount - grpc_static_metadata_refcounts))
+  (static_cast<intptr_t>(                        \
+      ((static_slice).refcount - grpc_static_metadata_refcounts)))
 
 #define GRPC_STATIC_MDELEM_COUNT 86
 extern grpc_mdelem_data grpc_static_mdelem_table[GRPC_STATIC_MDELEM_COUNT];
@@ -527,7 +530,7 @@ extern uintptr_t grpc_static_mdelem_user_data[GRPC_STATIC_MDELEM_COUNT];
 #define GRPC_MDELEM_ACCEPT_ENCODING_IDENTITY_COMMA_GZIP \
   (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[85], GRPC_MDELEM_STORAGE_STATIC))
 
-grpc_mdelem grpc_static_mdelem_for_static_strings(int a, int b);
+grpc_mdelem grpc_static_mdelem_for_static_strings(intptr_t a, intptr_t b);
 typedef enum {
   GRPC_BATCH_PATH,
   GRPC_BATCH_METHOD,
@@ -586,11 +589,11 @@ typedef union {
   } named;
 } grpc_metadata_batch_callouts;
 
-#define GRPC_BATCH_INDEX_OF(slice)                      \
+#define GRPC_BATCH_INDEX_OF(slice)                                        \
-  (GRPC_IS_STATIC_METADATA_STRING((slice))              \
+  (GRPC_IS_STATIC_METADATA_STRING((slice))                                \
-       ? (grpc_metadata_batch_callouts_index)GPR_CLAMP( \
+       ? static_cast<grpc_metadata_batch_callouts_index>(                 \
-             GRPC_STATIC_METADATA_INDEX((slice)), 0,    \
+             GPR_CLAMP(GRPC_STATIC_METADATA_INDEX((slice)), 0,            \
-             GRPC_BATCH_CALLOUTS_COUNT)                 \
+                       static_cast<intptr_t>(GRPC_BATCH_CALLOUTS_COUNT))) \
        : GRPC_BATCH_CALLOUTS_COUNT)
 
 extern const uint8_t grpc_static_accept_encoding_metadata[8];

tools/codegen/core/gen_static_metadata.py

@@ -376,6 +376,8 @@ print >> H, '#define GRPC_CORE_LIB_TRANSPORT_STATIC_METADATA_H'
 print >> H
 print >> H, '#include <grpc/support/port_platform.h>'
 print >> H
+print >> H, '#include <cstdint>'
+print >> H
 print >> H, '#include "src/core/lib/transport/metadata.h"'
 print >> H
 print >> C, '#include <grpc/support/port_platform.h>'
@@ -433,8 +435,8 @@ for i, elem in enumerate(all_strs):
 print >> C, '};'
 print >> C
 print >> H, '#define GRPC_STATIC_METADATA_INDEX(static_slice) \\'
-print >> H, ('  ((int)((static_slice).refcount - '
+print >> H, ('  (static_cast<intptr_t>(((static_slice).refcount - '
-             'grpc_static_metadata_refcounts))')
+             'grpc_static_metadata_refcounts)))')
 print >> H
 
 print >> D, '# hpack fuzzing dictionary'
@@ -537,10 +539,10 @@ print >> C, 'static const uint8_t elem_idxs[] = {%s};' % ','.join(
     '%d' % i for i in idxs)
 print >> C
 
-print >> H, 'grpc_mdelem grpc_static_mdelem_for_static_strings(int a, int b);'
+print >> H, 'grpc_mdelem grpc_static_mdelem_for_static_strings(intptr_t a, intptr_t b);'
-print >> C, 'grpc_mdelem grpc_static_mdelem_for_static_strings(int a, int b) {'
+print >> C, 'grpc_mdelem grpc_static_mdelem_for_static_strings(intptr_t a, intptr_t b) {'
 print >> C, '  if (a == -1 || b == -1) return GRPC_MDNULL;'
-print >> C, '  uint32_t k = (uint32_t)(a * %d + b);' % len(all_strs)
+print >> C, '  uint32_t k = static_cast<uint32_t>(a * %d + b);' % len(all_strs)
 print >> C, '  uint32_t h = elems_phash(k);'
 print >> C, '  return h < GPR_ARRAY_SIZE(elem_keys) && elem_keys[h] == k && elem_idxs[h] != 255 ? GRPC_MAKE_MDELEM(&grpc_static_mdelem_table[elem_idxs[h]], GRPC_MDELEM_STORAGE_STATIC) : GRPC_MDNULL;'
 print >> C, '}'
@@ -566,7 +568,7 @@ print >> H, '  } named;'
 print >> H, '} grpc_metadata_batch_callouts;'
 print >> H
 print >> H, '#define GRPC_BATCH_INDEX_OF(slice) \\'
-print >> H, '  (GRPC_IS_STATIC_METADATA_STRING((slice)) ? (grpc_metadata_batch_callouts_index)GPR_CLAMP(GRPC_STATIC_METADATA_INDEX((slice)), 0, GRPC_BATCH_CALLOUTS_COUNT) : GRPC_BATCH_CALLOUTS_COUNT)'
+print >> H, '  (GRPC_IS_STATIC_METADATA_STRING((slice)) ? static_cast<grpc_metadata_batch_callouts_index>(GPR_CLAMP(GRPC_STATIC_METADATA_INDEX((slice)), 0, static_cast<intptr_t>(GRPC_BATCH_CALLOUTS_COUNT))) : GRPC_BATCH_CALLOUTS_COUNT)'
 print >> H
 
 print >> H, 'extern const uint8_t grpc_static_accept_encoding_metadata[%d];' % (

tools/doxygen/Doxyfile.c++.internal

@@ -1188,6 +1188,7 @@ src/core/lib/slice/percent_encoding.h \
 src/core/lib/slice/slice_hash_table.h \
 src/core/lib/slice/slice_internal.h \
 src/core/lib/slice/slice_string_helpers.h \
+src/core/lib/slice/slice_utils.h \
 src/core/lib/slice/slice_weak_hash_table.h \
 src/core/lib/surface/api_trace.h \
 src/core/lib/surface/call.h \

tools/doxygen/Doxyfile.core.internal

@@ -1451,6 +1451,7 @@ src/core/lib/slice/slice_intern.cc \
 src/core/lib/slice/slice_internal.h \
 src/core/lib/slice/slice_string_helpers.cc \
 src/core/lib/slice/slice_string_helpers.h \
+src/core/lib/slice/slice_utils.h \
 src/core/lib/slice/slice_weak_hash_table.h \
 src/core/lib/surface/README.md \
 src/core/lib/surface/api_trace.cc \

tools/run_tests/generated/sources_and_headers.json

@@ -8574,6 +8574,7 @@
       "src/core/lib/slice/slice_hash_table.h", 
       "src/core/lib/slice/slice_internal.h", 
       "src/core/lib/slice/slice_string_helpers.h", 
+      "src/core/lib/slice/slice_utils.h", 
       "src/core/lib/slice/slice_weak_hash_table.h", 
       "src/core/lib/surface/api_trace.h", 
       "src/core/lib/surface/call.h", 
@@ -8730,6 +8731,7 @@
       "src/core/lib/slice/slice_hash_table.h", 
       "src/core/lib/slice/slice_internal.h", 
       "src/core/lib/slice/slice_string_helpers.h", 
+      "src/core/lib/slice/slice_utils.h", 
       "src/core/lib/slice/slice_weak_hash_table.h", 
       "src/core/lib/surface/api_trace.h", 
       "src/core/lib/surface/call.h",