Add utility to trace creation of problematic IRInsts to assist LLM in debugging (#7820)

* Initial plan

* Add SLANG_DEBUG_IR_BREAK environment variable support

Co-authored-by: csyonghe <2652293+csyonghe@users.noreply.github.com>

* Apply code formatting to SLANG_DEBUG_IR_BREAK implementation

Co-authored-by: csyonghe <2652293+csyonghe@users.noreply.github.com>

* Improve stack trace debugging with -rdynamic flag and backtrace_symbols

Co-authored-by: csyonghe <2652293+csyonghe@users.noreply.github.com>

* Address PR feedback: use PlatformUtil::getEnvironmentVariable, remove -rdynamic flag, and delete fallback branch

Co-authored-by: csyonghe <2652293+csyonghe@users.noreply.github.com>

* Address PR feedback: simplify env var parsing, move backtrace to PlatformUtil, use #if for SLANG_LINUX_FAMILY

Co-authored-by: csyonghe <2652293+csyonghe@users.noreply.github.com>

* Address PR feedback: remove unneeded include, make backtrace() more generic by removing uid parameter

Co-authored-by: csyonghe <2652293+csyonghe@users.noreply.github.com>

* Fix and clone source tracking.

* Add python script to dump traces.

* Update instructions.

* Batch calls to addr2line

* Cleanup claude instructions.

* update claude action.

* Remove duplicated build instructions from claude.yml workflow

Co-authored-by: csyonghe <2652293+csyonghe@users.noreply.github.com>

* fix build error.

* Fix build errors

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: csyonghe <2652293+csyonghe@users.noreply.github.com>
Co-authored-by: Yong He <yonghe@outlook.com>
Co-authored-by: Gangzheng Tong <tonggangzheng@gmail.com>

2 files changed, 13 insertions, 15 deletions

diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md
index 8475f70f5..00d8350fd 100644
--- a/.github/copilot-instructions.md
+++ b/.github/copilot-instructions.md
@@ -23,6 +23,17 @@ Add the "pr: breaking" label to  your PR if you are introducing public API chang
 or you are introducing changes to the Slang language that will cause the compiler to error out on existing Slang code.
 It is rare for a PR to be a breaking change.
 
+## Debugging
+
+If you encounter a bug related to a problematic instruction, it is often useful to trace the location where the instruction is created.
+You can use the `extras/insttrace.py` script to do this. For example, during debugging you find that an instruction with `_debugUID=1234`
+is wrong, you can run the following command to trace the callstack where the instruction is created:
+
+```bash
+# From workspace root:
+python3 ./extras/insttrace.py 1234 ./build/Debug/bin/slangc tests/my-test.slang -target spirv
+```
+
 ## Testing
 
 Your PR should include a regression test for the bug you are fixing.
diff --git a/.github/workflows/claude.yml b/.github/workflows/claude.yml
index dcc36e760..c2e0fb68e 100644
--- a/.github/workflows/claude.yml
+++ b/.github/workflows/claude.yml
@@ -189,19 +189,14 @@ jobs:
       # Run Claude Code Action with optimized environment variables
       - name: Execute Claude Code Action # Right now direct prompt to automatic PR Review
         id: claude-action
-        uses: anthropics/claude-code-action@v0.0.31
+        uses: anthropics/claude-code-action@v0.0.38
         with:
           # Direct Prompt is for testing. We shall use the triggers (on) which shall trigger this part on runtime
           custom_instructions: |
             # Build system information:
             - OS: Ubuntu Linux
-            - Build commands: 
-              * Configure: `cmake --preset default`
-              * Build: `cmake --build --preset debug`
-              * Test: `./build/Release/bin/slang-test ./tests/path/to/test.slang`
-              * Format code: `./extras/formatting.sh`
             - Project is pre-built and ready for development tasks
-            - Run formatting script before committing changes
+            - See CLAUDE.md for detailed build, test, and formatting instructions
 
             # CRITICAL: You have access to the mcp__deepwiki__ask_question tool for deep repository knowledge.
 
@@ -215,14 +210,6 @@ jobs:
               - Always follow existing code patterns and architectural decisions discovered through deepwiki
               - Consult the tool when you need context about unfamiliar parts of the codebase
 
-            # Debugging backend crashes or invalid downstream code:
-
-              Note that any issues in the generated target code could stem from IR passes or even the front-end type checking
-              early in the pipeline, and you need to focus on tracking the root cause that breaks the consistency/invariants/assumptions
-              of the IR instead of putting in band-aid fixes in the later passes or in the emit logic. The philosphy of the compiler is to
-              keep the target code emission logic as simple and direct as possible, and most of the heavy lifting code transform is done
-              in the IR passes.
-
           mcp_config: |
             {
               "mcpServers": {