feat(build): #243 #244 strip .eh_frame on release builds across all GCC platforms

crates/fbuild-build/Cargo.toml

@@ -29,3 +29,4 @@ tempfile = { workspace = true }
 filetime = { workspace = true }
 fbuild-test-support = { path = "../fbuild-test-support" }
 tar = { workspace = true }
+object = { workspace = true }

crates/fbuild-build/src/apollo3/orchestrator.rs

@@ -36,6 +36,10 @@ impl BuildOrchestrator for Apollo3Orchestrator {
         // 1-2. Parse config, load board, setup build dirs, resolve src dir, collect flags
         let mut ctx = pipeline::BuildContext::new(params)?;
 
+        // Compute eh_frame strip policy once per build (FastLED/fbuild#244).
+        let eh_frame_policy =
+            crate::eh_frame_policy_compute::compute_eh_frame_policy(&ctx, params.profile, None);
+
         // 3. Ensure ARM GCC 8 toolchain (Apollo3/mbed-os requires GCC 8)
         let toolchain = fbuild_packages::toolchain::ArmGcc8Toolchain::new(&params.project_dir);
         let toolchain_dir = fbuild_packages::Package::ensure_installed(&toolchain)?;
@@ -182,7 +186,8 @@ impl BuildOrchestrator for Apollo3Orchestrator {
             params.profile,
             params.verbose,
         )
-        .with_build_unflags(ctx.build_unflags.clone());
+        .with_build_unflags(ctx.build_unflags.clone())
+        .with_eh_frame_policy(eh_frame_policy);
 
         // 8. Create linker
         let linker_script = framework.get_linker_script();

crates/fbuild-build/src/avr/avr_compiler.rs

@@ -10,6 +10,7 @@ use fbuild_core::{BuildProfile, Result};
 
 use super::mcu_config::AvrMcuConfig;
 use crate::compiler::{CompileResult, Compiler, CompilerBase};
+use crate::eh_frame_policy::EhFramePolicy;
 
 /// AVR-specific compiler using avr-gcc and avr-g++.
 pub struct AvrCompiler {
@@ -22,6 +23,10 @@ pub struct AvrCompiler {
     /// PlatformIO `build_unflags` to strip from the effective compile
     /// line. See FastLED/fbuild#37.
     build_unflags: Vec<String>,
+    /// Whether to strip eh_frame unwinding tables. Default `Preserve` so existing
+    /// callers see no behavior change; orchestrators set this via
+    /// [`Self::with_eh_frame_policy`]. See FastLED/fbuild#244.
+    eh_frame_policy: EhFramePolicy,
 }
 
 impl AvrCompiler {
@@ -51,6 +56,7 @@ impl AvrCompiler {
             profile,
             temp_dir: fbuild_core::response_file::windows_temp_dir(),
             build_unflags: Vec::new(),
+            eh_frame_policy: EhFramePolicy::default(),
         }
     }
 
@@ -61,6 +67,13 @@ impl AvrCompiler {
         self
     }
 
+    /// Attach the eh_frame strip/preserve policy decided by the orchestrator.
+    /// Default `Preserve` keeps existing behavior. See FastLED/fbuild#244.
+    pub fn with_eh_frame_policy(mut self, policy: EhFramePolicy) -> Self {
+        self.eh_frame_policy = policy;
+        self
+    }
+
     /// Build the common AVR compiler flags.
     fn common_flags(&self) -> Vec<String> {
         let mut flags = vec![format!("-mmcu={}", self.base.mcu)];
@@ -73,6 +86,14 @@ impl AvrCompiler {
 
         flags.extend(self.base.build_define_flags());
         flags.extend(self.base.build_include_flags());
+
+        if matches!(self.eh_frame_policy, EhFramePolicy::Strip) {
+            flags.extend(
+                crate::eh_frame_policy::STRIP_FLAGS
+                    .iter()
+                    .map(|s| s.to_string()),
+            );
+        }
         flags
     }
 }
@@ -198,4 +219,22 @@ mod tests {
         assert!(flags.contains(&"-std=gnu++11".to_string()));
         assert!(flags.contains(&"-fno-exceptions".to_string()));
     }
+
+    /// FastLED/fbuild#244: default policy must not leak STRIP_FLAGS.
+    #[test]
+    fn cpp_flags_preserve_eh_frame_by_default() {
+        let compiler = test_compiler();
+        let flags = compiler.cpp_flags();
+        assert!(!flags.iter().any(|f| f == "-fno-asynchronous-unwind-tables"));
+        assert!(!flags.iter().any(|f| f == "-fno-unwind-tables"));
+    }
+
+    /// FastLED/fbuild#244: Strip policy must inject both unwind-table flags.
+    #[test]
+    fn cpp_flags_strip_eh_frame_when_policy_set() {
+        let compiler = test_compiler().with_eh_frame_policy(EhFramePolicy::Strip);
+        let flags = compiler.cpp_flags();
+        assert!(flags.iter().any(|f| f == "-fno-asynchronous-unwind-tables"));
+        assert!(flags.iter().any(|f| f == "-fno-unwind-tables"));
+    }
 }

crates/fbuild-build/src/avr/orchestrator.rs

@@ -57,6 +57,7 @@ struct AvrFingerprintMetadata {
     platform: String,
     max_flash: Option<u64>,
     max_ram: Option<u64>,
+    eh_frame_policy: &'static str,
 }
 
 fn profile_label(profile: fbuild_core::BuildProfile) -> &'static str {
@@ -90,6 +91,11 @@ impl BuildOrchestrator for AvrOrchestrator {
         //      the shared `perf` timer.
         let mut ctx = pipeline::BuildContext::new_with_perf(params, Some(&mut perf))?;
 
+        // Compute eh_frame strip policy once per build (FastLED/fbuild#244).
+        // No sdkconfig on AVR.
+        let eh_frame_policy =
+            crate::eh_frame_policy_compute::compute_eh_frame_policy(&ctx, params.profile, None);
+
         // 3. Ensure toolchain
         let (toolchain, toolchain_dir) = {
             let _g = perf.phase("toolchain-ensure");
@@ -138,6 +144,10 @@ impl BuildOrchestrator for AvrOrchestrator {
             platform: "atmelavr".to_string(),
             max_flash: ctx.board.max_flash,
             max_ram: ctx.board.max_ram,
+            eh_frame_policy: match eh_frame_policy {
+                crate::eh_frame_policy::EhFramePolicy::Strip => "strip",
+                crate::eh_frame_policy::EhFramePolicy::Preserve => "preserve",
+            },
         })?;
         let (fast_elf, [fast_hex], fast_compile_db) =
             expected_fast_path_artifacts(build_dir, &params.project_dir, ["firmware.hex"]);
@@ -224,7 +234,8 @@ impl BuildOrchestrator for AvrOrchestrator {
             params.profile,
             params.verbose,
         )
-        .with_build_unflags(ctx.build_unflags.clone());
+        .with_build_unflags(ctx.build_unflags.clone())
+        .with_eh_frame_policy(eh_frame_policy);
 
         // 7. Create linker
         let linker = AvrLinker::new(