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benvanikclaude
benvanik
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claude
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Replace libc printf with eyalroz/printf and add streaming status formatting.
Integrates eyalroz/printf as a vendored dependency to replace all libc snprintf/vsnprintf calls across the runtime. This gives us a consistent, portable printf implementation across all platforms (including embedded and bare-metal targets) with no platform-specific quirks. Beyond the drop-in replacement, this extends the status formatting API with streaming support: - Add iree_status_format_to: callback-based streaming formatter that avoids contiguous buffers and pre-measurement passes. The callback returns bool for flow control, enabling early termination on buffer full or allocation failure. - Add iree_string_builder_append_status: single-pass status-to-builder formatting via iree_status_format_to, resolving the status/string_builder dependency cycle that previously required a local copy in libhsa.c. - Rewrite iree_status_fprint to stream directly to FILE* with zero heap allocation (previously required a contiguous buffer). - Rewrite iree_status_to_string as single-pass using string builder instead of two-pass measure-then-format. - Fix va_copy usage in status allocation: use C99 va_copy for the two-pass measure-then-format pattern instead of calling va_start twice on the same parameter (implementation-defined behavior). - Convert Status::ToString (C++) and ApiStatusToString (Python bindings) from two-pass iree_status_format to single-pass iree_status_format_to. - Replace HIP dynamic_symbols.c allocate-format-free pattern with direct iree_string_builder_append_status (eliminates intermediate heap allocation). RISC-V toolchain fix: strip debug info from libgcc.a during CMake configure. eyalroz/printf's long double support in %Lf/%Le compiles va_arg(args, long double) which on RISC-V (128-bit quad precision) generates references to __extenddftf2/__trunctfdf2 soft-float builtins. These are resolved from libgcc.a, but the GCC 12.2.0-compiled objects in that archive contain DWARF debug info with relocation types 60/61 (in .debug_rnglists and .debug_loclists sections) that LLD cannot parse. The pre-built RISC-V toolchain lacks compiler-rt builtins as an alternative, so we strip the debug metadata from libgcc.a at configure time using llvm-objcopy --strip-debug. This preserves all code and data sections and is idempotent. The strip runs inside the RISCV_TOOLCHAIN_ROOT guard so users with their own toolchains are unaffected. Verified locally with the same toolchain used in CI (toolchain_iree_manylinux_2_28_20231012). Co-Authored-By: Claude <[email protected]>
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72 files changed

Lines changed: 940 additions & 413 deletions

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‎.gitmodules‎

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

‎CMakeLists.txt‎

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

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

‎build_tools/bazel/extensions.bzl‎

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

‎build_tools/bazel_to_cmake/bazel_to_cmake_targets.py‎

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

‎build_tools/cmake/linux_riscv64.cmake‎

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

‎build_tools/scripts/git/runtime_submodules.txt‎

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

‎build_tools/third_party/printf/BUILD.overlay‎

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

‎build_tools/third_party/printf/CMakeLists.txt‎

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

‎runtime/bindings/python/status_utils.cc‎

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

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