Check for panic-causing printfs when compiling without PGDEBUG

.github/workflows/build.yml

@@ -136,12 +136,28 @@ jobs:
         run: |
           mkdir -p $STAGING_DIR
           cp pgusinit/README.md $STAGING_DIR/README.md
-      - name: Get Tags
-        id: tag
-        uses: ildug/get-tag-action@v1
-      - name: Generate release body
+      - name: Classify release
+        id: relinfo
+        shell: bash
         run: |
-          awk '/^# v${{ steps.tag.outputs.version }}/{a=1;next}/^# /{a=0}a' sw/CHANGELOG.md > release-body.md
+          VERSION="${GITHUB_REF_NAME#v}"
+          echo "version=$VERSION" >> "$GITHUB_OUTPUT"
+          if [[ "$VERSION" == *-* ]]; then
+            echo "prerelease=true" >> "$GITHUB_OUTPUT"
+            echo "base_version=${VERSION%%-*}" >> "$GITHUB_OUTPUT"
+          else
+            echo "prerelease=false" >> "$GITHUB_OUTPUT"
+            echo "base_version=$VERSION" >> "$GITHUB_OUTPUT"
+          fi
+      - name: Generate release body
+        shell: bash
+        run: |
+          VERSION="${{ steps.relinfo.outputs.version }}"
+          BASE="${{ steps.relinfo.outputs.base_version }}"
+          awk -v ver="$VERSION" '$0 ~ "^# v" ver "$" {a=1;next} /^# /{a=0} a' sw/CHANGELOG.md > release-body.md
+          if [ ! -s release-body.md ] && [ "$VERSION" != "$BASE" ]; then
+            awk -v ver="$BASE" '$0 ~ "^# v" ver "$" {a=1;next} /^# /{a=0} a' sw/CHANGELOG.md > release-body.md
+          fi
       - name: Download firmware artifact
         uses: actions/download-artifact@v4
         with:
@@ -156,11 +172,12 @@ jobs:
         uses: montudor/action-zip@v1
       - name: Zip release
         run: |
-          zip -9 -r ../picogus-v${{ steps.tag.outputs.version }}.zip .
+          zip -9 -r ../picogus-v${{ steps.relinfo.outputs.version }}.zip .
         working-directory: ${{env.STAGING_DIR}}
       - name: Release
         uses: softprops/action-gh-release@v1
         with:
           body_path: release-body.md
-          files: picogus-v${{ steps.tag.outputs.version }}.zip
+          files: picogus-v${{ steps.relinfo.outputs.version }}.zip
           draft: true
+          prerelease: ${{ steps.relinfo.outputs.prerelease }}

sw/CMakeLists.txt

@@ -56,6 +56,7 @@ endfunction()
 
 
 option(PGDEBUG "Enable debug printf framework" OFF)
+find_package(Python3 COMPONENTS Interpreter QUIET)
 
 # Global definitions across all targets
 add_compile_definitions(
@@ -246,6 +247,18 @@ function(config_target TARGET_NAME MULTIFW)
         endif()
         pico_set_printf_implementation(${TARGET_NAME} none)
     endif()
+    if(NOT PGDEBUG AND Python3_FOUND)
+        # With printf stripped, __wrap_snprintf is the panic stub, so any
+        # stray printf call dead-loops the firmware. Fail the build if we
+        # find one.
+        add_custom_command(TARGET ${TARGET_NAME} POST_BUILD
+            COMMAND ${Python3_EXECUTABLE}
+                ${CMAKE_SOURCE_DIR}/scripts/check_printf_leak.py
+                ${CMAKE_OBJDUMP} ${CMAKE_ADDR2LINE}
+                $<TARGET_FILE:${TARGET_NAME}>
+            VERBATIM
+        )
+    endif()
     pico_enable_stdio_semihosting(${TARGET_NAME} 0)
 endfunction()
 
@@ -518,6 +531,7 @@ function(build_psg TARGET_NAME MULTIFW)
     )
     target_sources(${TARGET_NAME} PRIVATE
         audio/volctrl.cpp
+        audio/audio_i2s_minimal.c
         square/square.cpp
     )
     target_sources(${TARGET_NAME} PRIVATE psgplay.cpp)
@@ -534,9 +548,12 @@ function(build_usb TARGET_NAME MULTIFW)
     pico_set_program_name(${TARGET_NAME} "picogus-usb")
     target_compile_definitions(${TARGET_NAME} PRIVATE
         USB_ONLY=1
+        USE_CD_AUDIO_FIFO=1
     )
     target_sources(${TARGET_NAME} PRIVATE
         audio/volctrl.cpp
+        audio/audio_fifo.c
+        audio/audio_i2s_minimal.c
         usbplay.cpp
     )
 endfunction()
@@ -665,6 +682,15 @@ if(PROJECT_TYPE STREQUAL "MULTIFW")
     if(NOT PGDEBUG)
         pico_set_printf_implementation(bootloader none)
     endif()
+    if(NOT PGDEBUG AND Python3_FOUND)
+        add_custom_command(TARGET bootloader POST_BUILD
+            COMMAND ${Python3_EXECUTABLE}
+                ${CMAKE_SOURCE_DIR}/scripts/check_printf_leak.py
+                ${CMAKE_OBJDUMP} ${CMAKE_ADDR2LINE}
+                $<TARGET_FILE:bootloader>
+            VERBATIM
+        )
+    endif()
     add_dependencies(bootloader generate_flash_firmware_h)
 
     if (NOT UF2CREATE_FOUND)

sw/scripts/check_printf_leak.py

@@ -0,0 +1,68 @@
+#!/usr/bin/env python3
+
+# Used to fail the build if any non-panic code calls the raw printf-family
+# wrappers that route to printf_none_assert.
+
+import re
+import subprocess
+import sys
+
+
+def main(argv: list[str]) -> int:
+    if len(argv) != 4:
+        print(
+            "usage: check_printf_leak.py <objdump> <addr2line> <elf>",
+            file=sys.stderr,
+        )
+        return 2
+
+    objdump, addr2line, elf = argv[1:4]
+
+    dis = subprocess.run(
+        [objdump, "-d", elf], check=True, capture_output=True, text=True
+    ).stdout
+
+    offenders = []
+    call_re = re.compile(
+        r"^\s*([0-9a-f]+):\s.*\bbl\s+[0-9a-f]+\s+<(__wrap_v?s?n?printf)>"
+    )
+    for line in dis.splitlines():
+        m = call_re.match(line)
+        if not m:
+            continue
+        call_site, wrap = m.group(1), m.group(2)
+        res = subprocess.run(
+            [addr2line, "-fe", elf, call_site],
+            check=True,
+            capture_output=True,
+            text=True,
+        )
+        lines = res.stdout.strip().splitlines()
+        if not lines:
+            continue
+        caller = lines[0].strip()
+        # Skip pico_stdio wrappers calling each other internally
+        # (__wrap_printf -> __wrap_vprintf etc)
+        if caller.startswith("__wrap_"):
+            continue
+        location = lines[1].strip() if len(lines) > 1 else "<unknown>"
+        offenders.append((call_site, wrap, caller, location))
+
+    if not offenders:
+        return 0
+
+    print(
+        f"error: {elf} contains printf call(s) that will panic:",
+        file=sys.stderr,
+    )
+    for addr, wrap, caller, loc in offenders:
+        print(f"  {loc}: {caller}() -> {wrap} [@0x{addr}]", file=sys.stderr)
+    print(
+        "Replace with DBG_PRINTF from sw/include/pg_debug.h (no-ops when PGDEBUG is off).",
+        file=sys.stderr,
+    )
+    return 1
+
+
+if __name__ == "__main__":
+    sys.exit(main(sys.argv))