Use abseil for readable POSIX stack traces in debug builds

[tianleiwu]

Description

Replace glibc backtrace()/backtrace_symbols() with abseil's absl::GetStackTrace()/absl::Symbolize() for POSIX/Linux debug builds, and add automatic addr2line resolution for file paths and line numbers. The previous implementation produced raw addresses requiring manual addr2line translation. The new implementation produces demangled function names with source locations directly in exception messages, with zero new dependencies.

Summary of Changes

Stack Trace Implementation

File	Change
onnxruntime/core/platform/posix/stacktrace.cc	Replace glibc backtrace()/backtrace_symbols() with absl::GetStackTrace()/absl::Symbolize(). Use dladdr() + addr2line to resolve source file and line number for each frame.
onnxruntime/core/session/environment.cc	Add one-time absl::InitializeSymbolizer(nullptr) call via std::call_once in Environment::Initialize(). On Linux, nullptr works because abseil reads /proc/self/exe.

Before vs After

Before (raw addresses requiring manual addr2line):

Stacktrace:
 /home/me/build/Debug/onnxruntime_test_all(+0x3f46cc) [0x559543faf6cc]
 /home/me/build/Debug/onnxruntime_test_all(+0x2bef04d) [0x559543faf6cc]

After (demangled function names + file:line):

Stacktrace:
onnxruntime::OpKernelContext::Output() at .../core/framework/op_kernel.cc:45
onnxruntime::Add<>::Compute() at .../core/providers/cpu/math/element_wise_ops.cc:596
onnxruntime::ExecuteKernel() at .../core/framework/sequential_executor.cc:535
onnxruntime::InferenceSession::Run() at .../core/session/inference_session.cc:3142
onnxruntime::test::...TestBody() at .../test/framework/execution_frame_test.cc:506

Motivation and Context

Follow-up on #26257, which was closed because abseil's backtrace/symbolize is already available as a dependency. This PR implements that suggestion with additional file:line resolution:

• No new dependency: absl::stacktrace and absl::symbolize are already in ABSEIL_LIBS and linked to onnxruntime_common. dladdr() and addr2line are standard POSIX/Linux utilities.
• No CMake changes needed: Everything is already wired up
• Debug-only: Guarded by #ifndef NDEBUG — no performance impact in release builds
• Best-effort file:line: Uses dladdr() to compute file offsets, then calls addr2line in batch (once per binary). Falls back gracefully to function-name-only output if addr2line is unavailable.
• Windows unchanged: Windows already has superior stack traces via C++23 <stacktrace>
• Platform exclusions preserved: Android, WebAssembly, AIX, and _OPSCHEMA_LIB_ builds continue to return empty stack traces

How it works

1. absl::GetStackTrace() captures raw frame addresses
2. absl::Symbolize() resolves each address to a demangled function name
3. dladdr() determines which binary each address belongs to and computes the file offset
4. addr2line is called in batch (one invocation per binary) to resolve file:line
5. Results are combined into a single readable string per frame

Testing

• Built and verified on Linux with CUDA EP in Debug mode
• Ran onnxruntime_test_all --gtest_filter="*BadModelInvalidDimParamUsage*" — confirmed stack trace shows demangled function names with file paths and line numbers through the full call chain
• Verified graceful fallback when addr2line cannot resolve a frame (shows function name + address only)
• No CMake changes, so no risk of build system regressions on other platforms

[Copilot]

Pull request overview

This PR updates ONNX Runtime’s POSIX/Linux debug stack trace generation to produce more readable, symbolized call stacks by switching from glibc backtrace()/backtrace_symbols() to Abseil’s stacktrace/symbolization APIs, with optional addr2line-based file:line resolution.

Changes:

• Replace glibc backtrace collection/symbol printing with absl::GetStackTrace() + absl::Symbolize() in POSIX debug builds.
• Add best-effort addr2line integration to resolve source file and line numbers for stack frames (opt-in via env var).
• Initialize Abseil’s symbolizer once during Environment::Initialize() on non-Windows POSIX platforms.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

File	Description
onnxruntime/core/session/environment.cc	Adds one-time Abseil symbolizer initialization during environment setup on non-Windows POSIX platforms.
onnxruntime/core/platform/posix/stacktrace.cc	Reworks debug stack trace capture/symbolization to use Abseil and optionally resolve file:line via addr2line.

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