From 0e958f5a4ba435a826ca95adc61a79e084e90121 Mon Sep 17 00:00:00 2001
From: Chris Fallin <chris@cfallin.org>
Date: Sun, 12 Feb 2023 11:37:52 -0800
Subject: [PATCH] Fix debuginfo parsing: actually supply all needed sections to
 addr2line.

---
 src/frontend.rs | 39 +++++++++++++++++++++++++++++++++++++--
 src/ir/debug.rs | 14 +++++++-------
 2 files changed, 44 insertions(+), 9 deletions(-)

diff --git a/src/frontend.rs b/src/frontend.rs
index 7a5bf97..ee6062f 100644
--- a/src/frontend.rs
+++ b/src/frontend.rs
@@ -21,11 +21,22 @@ pub fn wasm_to_ir(bytes: &[u8]) -> Result<Module<'_>> {
     let parser = Parser::new(0);
     let mut next_func = 0;
     let mut dwarf = gimli::Dwarf::default();
+    let mut extra_sections = ExtraSections::default();
     for payload in parser.parse_all(bytes) {
         let payload = payload?;
-        handle_payload(&mut module, payload, &mut next_func, &mut dwarf)?;
+        handle_payload(
+            &mut module,
+            payload,
+            &mut next_func,
+            &mut dwarf,
+            &mut extra_sections,
+        )?;
     }
-    let debug_map = DebugMap::from_dwarf(dwarf, &mut module.debug);
+    dwarf.locations =
+        gimli::LocationLists::new(extra_sections.debug_loc, extra_sections.debug_loclists);
+    dwarf.ranges =
+        gimli::RangeLists::new(extra_sections.debug_ranges, extra_sections.debug_rnglists);
+    let debug_map = DebugMap::from_dwarf(dwarf, &mut module.debug)?;
     module.debug_map = debug_map;
 
     Ok(module)
@@ -57,11 +68,20 @@ fn parse_init_expr<'a>(init_expr: &wasmparser::ConstExpr<'a>) -> Result<Option<u
     })
 }
 
+#[derive(Default)]
+struct ExtraSections<'a> {
+    debug_loc: gimli::DebugLoc<gimli::EndianSlice<'a, gimli::LittleEndian>>,
+    debug_loclists: gimli::DebugLocLists<gimli::EndianSlice<'a, gimli::LittleEndian>>,
+    debug_ranges: gimli::DebugRanges<gimli::EndianSlice<'a, gimli::LittleEndian>>,
+    debug_rnglists: gimli::DebugRngLists<gimli::EndianSlice<'a, gimli::LittleEndian>>,
+}
+
 fn handle_payload<'a>(
     module: &mut Module<'a>,
     payload: Payload<'a>,
     next_func: &mut usize,
     dwarf: &mut gimli::Dwarf<gimli::EndianSlice<'a, gimli::LittleEndian>>,
+    extra_sections: &mut ExtraSections<'a>,
 ) -> Result<()> {
     trace!("Wasm parser item: {:?}", payload);
     match payload {
@@ -249,6 +269,21 @@ fn handle_payload<'a>(
         Payload::CustomSection(reader) if reader.name() == ".debug_types" => {
             dwarf.debug_types = gimli::DebugTypes::new(reader.data(), gimli::LittleEndian);
         }
+        Payload::CustomSection(reader) if reader.name() == ".debug_loc" => {
+            extra_sections.debug_loc = gimli::DebugLoc::new(reader.data(), gimli::LittleEndian);
+        }
+        Payload::CustomSection(reader) if reader.name() == ".debug_loclists" => {
+            extra_sections.debug_loclists =
+                gimli::DebugLocLists::new(reader.data(), gimli::LittleEndian);
+        }
+        Payload::CustomSection(reader) if reader.name() == ".debug_ranges" => {
+            extra_sections.debug_ranges =
+                gimli::DebugRanges::new(reader.data(), gimli::LittleEndian);
+        }
+        Payload::CustomSection(reader) if reader.name() == ".debug_rnglists" => {
+            extra_sections.debug_rnglists =
+                gimli::DebugRngLists::new(reader.data(), gimli::LittleEndian);
+        }
         Payload::CustomSection(_) => {}
         Payload::CodeSectionStart { .. } => {}
         Payload::Version { .. } => {}
diff --git a/src/ir/debug.rs b/src/ir/debug.rs
index 5602cca..7568243 100644
--- a/src/ir/debug.rs
+++ b/src/ir/debug.rs
@@ -55,8 +55,8 @@ impl DebugMap {
     pub(crate) fn from_dwarf<R: gimli::Reader>(
         dwarf: gimli::Dwarf<R>,
         debug: &mut Debug,
-    ) -> DebugMap {
-        let ctx = addr2line::Context::from_dwarf(dwarf).unwrap();
+    ) -> anyhow::Result<DebugMap> {
+        let ctx = addr2line::Context::from_dwarf(dwarf)?;
         let mut tuples = vec![];
 
         let mut locs = ctx.find_location_range(0, u64::MAX).unwrap();
@@ -66,13 +66,13 @@ impl DebugMap {
             tuples.push((start as u32, end as u32, loc));
         }
 
-        log::trace!("tuples:");
+        println!("tuples:");
         for &(start, end, loc) in &tuples {
-            log::trace!(" {:x} - {:x}: {}", start, end, loc);
+            println!(" {:x} - {:x}: {}", start, end, loc);
         }
-        log::trace!("files: {:?}", debug.source_files);
-        log::trace!("locs: {:?}", debug.source_locs);
+        println!("files: {:?}", debug.source_files);
+        println!("locs: {:?}", debug.source_locs);
 
-        DebugMap { tuples }
+        Ok(DebugMap { tuples })
     }
 }