Replace libc printf with eyalroz/printf and add streaming status formatting.

.gitmodules

@@ -37,3 +37,6 @@
 [submodule "third_party/hsa-runtime-headers"]
 	path = third_party/hsa-runtime-headers
 	url = https://github.com/iree-org/hsa-runtime-headers.git
+[submodule "third_party/printf"]
+	path = third_party/printf
+	url = https://github.com/eyalroz/printf.git

CMakeLists.txt

@@ -1042,6 +1042,9 @@ if(IREE_ENABLE_CPUINFO)
   endif()
 endif()
 
+# Platform-independent printf implementation (eyalroz/printf).
+add_subdirectory(build_tools/third_party/printf EXCLUDE_FROM_ALL)
+
 # This defines the iree-flatcc-cli target, so we don't use EXCLUDE_FROM_ALL.
 add_subdirectory(build_tools/third_party/flatcc)
 

MODULE.bazel

@@ -80,6 +80,7 @@ use_repo(
     "iree_cuda",
     "llvm-raw",
     "nccl",
+    "printf_lib",
     "rccl",
     "spirv_cross",
     "stablehlo",

build_tools/bazel/extensions.bzl

@@ -96,6 +96,13 @@ def _iree_extension_impl(module_ctx):
         path = "third_party/rccl",
     )
 
+    # eyalroz/printf (platform-independent printf implementation)
+    new_local_repository(
+        name = "printf_lib",
+        build_file = "@iree_core//:build_tools/third_party/printf/BUILD.overlay",
+        path = "third_party/printf",
+    )
+
     # WebGPU headers
     new_local_repository(
         name = "webgpu_headers",

build_tools/bazel_to_cmake/bazel_to_cmake_targets.py

@@ -119,6 +119,7 @@ def __init__(self, repo_map: Dict[str, str]):
                 "@vulkan_headers": ["Vulkan::Headers"],
                 # Misc single targets
                 "@com_google_benchmark//:benchmark": ["benchmark"],
+                "@printf_lib//:printf": ["printf::printf"],
                 "@com_github_dvidelabs_flatcc//:flatcc": ["flatcc"],
                 "@com_github_dvidelabs_flatcc//:parsing": ["flatcc::parsing"],
                 "@com_github_dvidelabs_flatcc//:runtime": ["flatcc::runtime"],

build_tools/cmake/linux_riscv64.cmake

@@ -26,6 +26,22 @@ if(NOT "${RISCV_TOOLCHAIN_ROOT}" STREQUAL "")
   set(CMAKE_RANLIB       "${RISCV_TOOLCHAIN_ROOT}/bin/${RISCV_TOOLCHAIN_PREFIX}llvm-ranlib")
   set(CMAKE_STRIP        "${RISCV_TOOLCHAIN_ROOT}/bin/${RISCV_TOOLCHAIN_PREFIX}llvm-strip")
   set(CMAKE_SYSROOT "${RISCV_TOOLCHAIN_ROOT}/sysroot")
+  # Strip debug info from libgcc.a to work around LLD incompatibility. The
+  # GCC 12.2.0-compiled libgcc.a contains DWARF debug info with relocations
+  # that LLD cannot parse (unknown relocation types 60/61 in .debug_rnglists
+  # and .debug_loclists sections). Code and data sections are unaffected;
+  # only debug metadata is removed. This is idempotent.
+  file(GLOB_RECURSE _LIBGCC_ARCHIVES "${RISCV_TOOLCHAIN_ROOT}/lib/gcc/*/libgcc.a")
+  foreach(_LIBGCC IN LISTS _LIBGCC_ARCHIVES)
+    execute_process(
+      COMMAND "${RISCV_TOOLCHAIN_ROOT}/bin/${RISCV_TOOLCHAIN_PREFIX}llvm-objcopy"
+              --strip-debug "${_LIBGCC}"
+      RESULT_VARIABLE _strip_result
+    )
+    if(NOT _strip_result EQUAL 0)
+      message(WARNING "Failed to strip debug from ${_LIBGCC}")
+    endif()
+  endforeach()
 endif()
 
 # Specify ISA spec for march=rv64gc. This is to resolve the mismatch between

build_tools/scripts/git/runtime_submodules.txt

@@ -4,6 +4,7 @@ third_party/googletest
 third_party/hip-build-deps
 third_party/hsa-runtime-headers
 third_party/musl
+third_party/printf
 third_party/spirv_cross
 third_party/tracy
 third_party/vulkan_headers

build_tools/third_party/printf/BUILD.overlay

@@ -0,0 +1,23 @@
+# Copyright 2026 The IREE Authors
+#
+# Licensed under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+package(default_visibility = ["//visibility:public"])
+
+cc_library(
+    name = "printf",
+    srcs = ["src/printf/printf.c"],
+    hdrs = ["src/printf/printf.h"],
+    copts = select({
+        "@bazel_tools//src/conditions:windows": [],
+        "//conditions:default": [
+            "-Wno-sign-conversion",
+        ],
+    }),
+    local_defines = [
+        "PRINTF_SUPPORT_WRITEBACK_SPECIFIER=0",
+    ],
+    strip_include_prefix = "src",
+)

build_tools/third_party/printf/CMakeLists.txt

@@ -0,0 +1,32 @@
+# Copyright 2026 The IREE Authors
+#
+# Licensed under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+set(PRINTF_ROOT "${IREE_ROOT_DIR}/third_party/printf/")
+
+# We don't install any headers because their only use is via the
+# iree/base/printf.h wrapper.
+set(IREE_HDRS_ROOT_PATH OFF)
+# Considered part of the runtime.
+set(IREE_INSTALL_LIBRARY_TARGETS_DEFAULT_COMPONENT IREEBundledLibraries)
+set(IREE_INSTALL_LIBRARY_TARGETS_DEFAULT_EXPORT_SET Runtime)
+
+external_cc_library(
+  PACKAGE
+    printf
+  NAME
+    printf
+  ROOT
+    ${PRINTF_ROOT}
+  INCLUDES
+    "${PRINTF_ROOT}/src"
+  SRCS
+    "src/printf/printf.c"
+  HDRS
+    "src/printf/printf.h"
+  COPTS
+    "-DPRINTF_SUPPORT_WRITEBACK_SPECIFIER=0"
+  PUBLIC
+)

runtime/bindings/python/status_utils.cc

@@ -29,18 +29,16 @@ PyObject* ApiStatusToPyExcClass(iree_status_t status) {
 }  // namespace
 
 std::string ApiStatusToString(iree_status_t status) {
-  iree_host_size_t buffer_length = 0;
-  if (IREE_UNLIKELY(!iree_status_format(status, /*buffer_capacity=*/0,
-                                        /*buffer=*/NULL, &buffer_length))) {
-    return "";
-  }
   std::string result;
-  result.resize(buffer_length);
-  // NOTE: buffer capacity needs to be +1 for the NUL terminator in snprintf.
-  return iree_status_format(status, result.size() + 1,
-                            const_cast<char*>(result.data()), &buffer_length)
-             ? result
-             : "";
+  iree_status_format_to(
+      status,
+      [](iree_string_view_t chunk, void* user_data) -> bool {
+        auto* str = static_cast<std::string*>(user_data);
+        str->append(chunk.data, chunk.size);
+        return true;
+      },
+      &result);
+  return result;
 }
 
 nanobind::python_error ApiStatusToPyExc(iree_status_t status,

runtime/src/iree/async/cts/socket/lifecycle_test.cc

@@ -662,7 +662,7 @@ TEST_P(SocketTest, MultipleExchanges) {
   for (int round = 0; round < 3; ++round) {
     // Prepare send data with round number embedded.
     char send_data[64];
-    snprintf(send_data, sizeof(send_data), "Message round %d", round);
+    iree_snprintf(send_data, sizeof(send_data), "Message round %d", round);
     iree_host_size_t send_length = strlen(send_data);
     iree_async_span_t send_span =
         iree_async_span_from_ptr((void*)send_data, send_length);

runtime/src/iree/async/cts/socket/posix_test.cc

@@ -43,8 +43,9 @@ class SocketPosixTest : public SocketTestBase<> {
   std::string UniqueAbstractName(const char* base_name) {
     static std::atomic<int> counter{0};
     char buffer[108];  // sun_path max
-    snprintf(buffer, sizeof(buffer), "@iree_cts_%s_%d_%d", base_name,
-             (int)getpid(), counter.fetch_add(1, std::memory_order_relaxed));
+    iree_snprintf(buffer, sizeof(buffer), "@iree_cts_%s_%d_%d", base_name,
+                  (int)getpid(),
+                  counter.fetch_add(1, std::memory_order_relaxed));
     return std::string(buffer);
   }
 };

runtime/src/iree/async/cts/socket/tcp_transfer_test.cc

@@ -745,7 +745,7 @@ TEST_P(ConcurrentConnectionsTest, ConcurrentConnections_Sequential) {
   // Verify each connection is independent by sending unique data.
   for (int i = 0; i < kNumConnections; ++i) {
     char send_data[32];
-    snprintf(send_data, sizeof(send_data), "Connection %d", i);
+    iree_snprintf(send_data, sizeof(send_data), "Connection %d", i);
     iree_host_size_t send_length = strlen(send_data);
 
     iree_async_span_t send_span =
@@ -856,7 +856,7 @@ TEST_P(ConcurrentConnectionsTest, ConcurrentConnections_Parallel) {
   CompletionTracker recv_trackers[kNumConnections];
 
   for (int i = 0; i < kNumConnections; ++i) {
-    snprintf(send_data[i], sizeof(send_data[i]), "Parallel %d", i);
+    iree_snprintf(send_data[i], sizeof(send_data[i]), "Parallel %d", i);
     send_spans[i] =
         iree_async_span_from_ptr((void*)send_data[i], strlen(send_data[i]));
 
@@ -975,8 +975,8 @@ TEST_P(ConcurrentConnectionsTest, ConcurrentConnections_Interleaved) {
 
     // Submit all sends and recvs for this round.
     for (int i = 0; i < kNumConnections; ++i) {
-      snprintf(send_data[i], sizeof(send_data[i]), "Round %d Conn %d", round,
-               i);
+      iree_snprintf(send_data[i], sizeof(send_data[i]), "Round %d Conn %d",
+                    round, i);
       send_spans[i] =
           iree_async_span_from_ptr((void*)send_data[i], strlen(send_data[i]));
 
@@ -1214,7 +1214,7 @@ TEST_P(ScatterGatherTest, ScatterGather_ManyBuffers) {
   iree_host_size_t total_length = 0;
 
   for (int i = 0; i < kNumBuffers; ++i) {
-    snprintf(buffers[i], sizeof(buffers[i]), "[Chunk %d]", i);
+    iree_snprintf(buffers[i], sizeof(buffers[i]), "[Chunk %d]", i);
     iree_host_size_t len = strlen(buffers[i]);
     spans[i] = iree_async_span_from_ptr(buffers[i], len);
     total_length += len;

runtime/src/iree/async/platform/io_uring/proactor.c

@@ -1605,8 +1605,9 @@ static iree_status_t iree_async_proactor_io_uring_import_file(
   file->primitive = primitive;
   file->fixed_file_index = -1;  // Not using io_uring fixed files yet.
 
-  IREE_TRACE(
-      { snprintf(file->debug_path, sizeof(file->debug_path), "fd:%d", fd); });
+  IREE_TRACE({
+    iree_snprintf(file->debug_path, sizeof(file->debug_path), "fd:%d", fd);
+  });
 
   *out_file = file;
   IREE_TRACE_ZONE_END(z0);

runtime/src/iree/async/platform/io_uring/socket.c

@@ -174,7 +174,8 @@ static void iree_async_socket_initialize(
   iree_atomic_store(&socket->failure_status, (intptr_t)iree_ok_status(),
                     iree_memory_order_release);
   IREE_TRACE({
-    snprintf(socket->debug_label, sizeof(socket->debug_label), "socket:%d", fd);
+    iree_snprintf(socket->debug_label, sizeof(socket->debug_label), "socket:%d",
+                  fd);
   });
 }
 

runtime/src/iree/async/platform/iocp/proactor.c

@@ -1742,9 +1742,10 @@ static iree_status_t iree_async_proactor_iocp_poll(
                                   (intptr_t)iree_ok_status(),
                                   iree_memory_order_release);
                 IREE_TRACE({
-                  snprintf(accepted_socket->debug_label,
-                           sizeof(accepted_socket->debug_label),
-                           "accepted:%llu", (unsigned long long)accept_sock);
+                  iree_snprintf(accepted_socket->debug_label,
+                                sizeof(accepted_socket->debug_label),
+                                "accepted:%llu",
+                                (unsigned long long)accept_sock);
                 });
                 accept_op->accepted_socket = accepted_socket;
               } else {
@@ -2317,8 +2318,8 @@ static iree_status_t iree_async_proactor_iocp_import_file(
   file->fixed_file_index = -1;
 
   IREE_TRACE({
-    snprintf(file->debug_path, sizeof(file->debug_path), "handle:%p",
-             (void*)handle);
+    iree_snprintf(file->debug_path, sizeof(file->debug_path), "handle:%p",
+                  (void*)handle);
   });
 
   *out_file = file;

runtime/src/iree/async/platform/iocp/socket.c

@@ -164,8 +164,8 @@ static void iree_async_iocp_socket_initialize(
   iree_atomic_store(&socket->failure_status, (intptr_t)iree_ok_status(),
                     iree_memory_order_release);
   IREE_TRACE({
-    snprintf(socket->debug_label, sizeof(socket->debug_label), "socket:%llu",
-             (unsigned long long)sock);
+    iree_snprintf(socket->debug_label, sizeof(socket->debug_label),
+                  "socket:%llu", (unsigned long long)sock);
   });
 }
 

runtime/src/iree/async/platform/posix/proactor.c

@@ -3124,7 +3124,7 @@ static iree_status_t iree_async_proactor_posix_import_file(
   IREE_TRACE({
     // For debugging, store a placeholder path since we don't know the actual
     // path for an imported fd.
-    snprintf(file->debug_path, sizeof(file->debug_path), "fd:%d", fd);
+    iree_snprintf(file->debug_path, sizeof(file->debug_path), "fd:%d", fd);
   });
 
   *out_file = file;

runtime/src/iree/async/platform/posix/socket.c

@@ -169,7 +169,8 @@ static void iree_async_socket_initialize(iree_async_socket_t* socket,
   iree_atomic_store(&socket->failure_status, (intptr_t)iree_ok_status(),
                     iree_memory_order_release);
   IREE_TRACE({
-    snprintf(socket->debug_label, sizeof(socket->debug_label), "socket:%d", fd);
+    iree_snprintf(socket->debug_label, sizeof(socket->debug_label), "socket:%d",
+                  fd);
   });
 }
 

runtime/src/iree/base/BUILD.bazel

@@ -34,6 +34,8 @@ iree_runtime_cc_library(
         "loop.h",
         "loop_inline.c",
         "loop_inline.h",
+        "printf.c",
+        "printf.h",
         "status.c",
         "status.h",
         "status_cc.h",
@@ -57,6 +59,7 @@ iree_runtime_cc_library(
         "//runtime/src/iree/base/internal",
         "//runtime/src/iree/base/internal:time",
         "//runtime/src/iree/base/tracing:provider",
+        "@printf_lib//:printf",
     ],
 )
 

runtime/src/iree/base/CMakeLists.txt

@@ -66,6 +66,8 @@ iree_cc_library(
     "loop.h"
     "loop_inline.c"
     "loop_inline.h"
+    "printf.c"
+    "printf.h"
     "status.c"
     "status.h"
     "status_cc.h"
@@ -88,6 +90,7 @@ iree_cc_library(
     iree::base::internal
     iree::base::internal::time
     iree::base::tracing::provider
+    printf::printf
     ${IREE_LIBBACKTRACE_TARGET}
     ${_IREE_ALLOCATOR_SYSTEM_DEPS}
   PUBLIC

runtime/src/iree/base/api.h

@@ -87,6 +87,7 @@
 #include "iree/base/config.h"          // IWYU pragma: export
 #include "iree/base/loop.h"            // IWYU pragma: export
 #include "iree/base/loop_inline.h"     // IWYU pragma: export
+#include "iree/base/printf.h"          // IWYU pragma: export
 #include "iree/base/status.h"          // IWYU pragma: export
 #include "iree/base/string_builder.h"  // IWYU pragma: export
 #include "iree/base/string_view.h"     // IWYU pragma: export

runtime/src/iree/base/internal/dynamic_library_posix.c

@@ -41,8 +41,8 @@ static iree_status_t iree_dynamic_library_make_temp_file_path(
     const char* tmpdir, char** out_file_path) {
   // Stamp in a unique file name (replacing XXXXXX in the string).
   char temp_path[512];
-  if (snprintf(temp_path, sizeof(temp_path), "%s/iree_dylib_XXXXXX", tmpdir) >=
-      sizeof(temp_path)) {
+  if (iree_snprintf(temp_path, sizeof(temp_path), "%s/iree_dylib_XXXXXX",
+                    tmpdir) >= sizeof(temp_path)) {
     // NOTE: we could dynamically allocate things, but didn't seem worth it.
     return iree_make_status(
         IREE_STATUS_INVALID_ARGUMENT,
@@ -57,15 +57,15 @@ static iree_status_t iree_dynamic_library_make_temp_file_path(
 
   // Allocate storage for the full file path and format it in.
   int file_path_length =
-      snprintf(NULL, 0, "%s_%s.%s", temp_path, prefix, extension);
+      iree_snprintf(NULL, 0, "%s_%s.%s", temp_path, prefix, extension);
   if (file_path_length < 0) {
     return iree_make_status(IREE_STATUS_INVALID_ARGUMENT,
                             "unable to form temp path string");
   }
   IREE_RETURN_IF_ERROR(iree_allocator_malloc(
       allocator, file_path_length + /*NUL=*/1, (void**)out_file_path));
-  snprintf(*out_file_path, file_path_length + /*NUL=*/1, "%s_%s.%s", temp_path,
-           prefix, extension);
+  iree_snprintf(*out_file_path, file_path_length + /*NUL=*/1, "%s_%s.%s",
+                temp_path, prefix, extension);
 
   // Canonicalize away any double path separators.
   iree_file_path_canonicalize(*out_file_path, file_path_length);