Implement no_std support

.travis.yml

@@ -49,3 +49,6 @@ matrix:
     # Benching should only happen on nightly with --release.
     - rust: nightly
       env: GIMLI_JOB="bench"    GIMLI_PROFILE="--release"
+    # alloc requires nightly.
+    - rust: nightly
+      env: GIMLI_JOB="build"    GIMLI_PROFILE="--no-default-features" GIMLI_FEATURES="alloc"

Cargo.toml

@@ -15,20 +15,20 @@ exclude = ["/benches/*", "/fixtures/*"]
 travis-ci = { repository = "gimli-rs/addr2line" }
 
 [dependencies]
-gimli = "0.16"
-fallible-iterator = "0.1"
-object = "0.9"
-intervaltree = "0.2"
-smallvec = "0.6"
+gimli = { version = "0.16", default-features = false }
+fallible-iterator = { version = "0.1", default-features = false }
+object = { version = "0.9", default-features = false }
+intervaltree = { version = "0.2", default-features = false }
+smallvec = { version = "0.6", default-features = false }
 lazycell = "1.0"
 rustc-demangle = { version = "0.1", optional = true }
-cpp_demangle = { version = "0.2", optional = true }
+cpp_demangle = { version = "0.2", default-features = false, optional = true }
 
 [dev-dependencies]
 memmap = "0.6"
 clap = "2"
 backtrace = "0.3"
-findshlibs = "0.3"
+findshlibs = "0.4"
 rustc-test = "0.3"
 
 [profile.release]
@@ -37,7 +37,9 @@ debug = true
 debug = true
 
 [features]
-default = ["rustc-demangle", "cpp_demangle"]
+default = ["rustc-demangle", "cpp_demangle", "std"]
+std = ["gimli/std", "intervaltree/std", "object/std", "smallvec/std"]
+alloc = ["gimli/alloc"]
 
 [[test]]
 name = "output_equivalence"

examples/addr2line.rs

@@ -47,9 +47,9 @@ fn print_loc(loc: &Option<Location>, basenames: bool, llvm: bool) {
     if let Some(ref loc) = *loc {
         let file = loc.file.as_ref().unwrap();
         let path = if basenames {
-            Path::new(file.file_name().unwrap())
+            Path::new(Path::new(file).file_name().unwrap())
         } else {
-            file
+            Path::new(file)
         };
         print!("{}:", path.display());
         if llvm {

src/lib.rs

@@ -22,6 +22,17 @@
 //! which is parsed using [`gimli`](https://github.com/gimli-rs/gimli).  The example CLI
 //! wrapper also uses symbol table information provided by the `object` crate.
 #![deny(missing_docs)]
+#![no_std]
+#![cfg_attr(not(feature = "std"), feature(alloc))]
+
+#[cfg(feature = "std")]
+#[macro_use]
+extern crate std;
+
+#[cfg(not(feature = "std"))]
+extern crate alloc;
+#[cfg(not(feature = "std"))]
+extern crate core as std;
 
 #[cfg(feature = "cpp_demangle")]
 extern crate cpp_demangle;
@@ -34,11 +45,18 @@ extern crate object;
 extern crate rustc_demangle;
 extern crate smallvec;
 
-use std::path::PathBuf;
+#[cfg(feature = "std")]
+mod alloc {
+    pub use std::{borrow, rc, string, vec};
+}
+
+use alloc::borrow::Cow;
+use alloc::rc::Rc;
+use alloc::string::{String, ToString};
+use alloc::vec::Vec;
+
 use std::cmp::Ordering;
-use std::borrow::Cow;
 use std::u64;
-use std::rc::Rc;
 
 use fallible_iterator::FallibleIterator;
 use intervaltree::{Element, IntervalTree};
@@ -438,7 +456,7 @@ impl<R: gimli::Reader> FallibleIterator for WrapRangeIter<R> {
 /// A source location.
 pub struct Location {
     /// The file name.
-    pub file: Option<PathBuf>,
+    pub file: Option<String>,
     /// The line number.
     pub line: Option<u64>,
     /// The column number.
@@ -562,23 +580,34 @@ where
         &self,
         file: &gimli::FileEntry<R>,
         lines: &Lines<R>,
-    ) -> Result<PathBuf, gimli::Error> {
+    ) -> Result<String, gimli::Error> {
         let mut path = if let Some(ref comp_dir) = self.comp_dir {
-            PathBuf::from(comp_dir.to_string_lossy()?.as_ref())
+            String::from(comp_dir.to_string_lossy()?.as_ref())
         } else {
-            PathBuf::new()
+            String::new()
         };
 
         if let Some(directory) = file.directory(lines.lnp.header()) {
-            path.push(directory.to_string_lossy()?.as_ref());
+            path_push(&mut path, directory.to_string_lossy()?.as_ref());
         }
 
-        path.push(file.path_name().to_string_lossy()?.as_ref());
+        path_push(&mut path, file.path_name().to_string_lossy()?.as_ref());
 
         Ok(path)
     }
 }
 
+fn path_push(path: &mut String, p: &str) {
+    if p.starts_with("/") {
+        *path = p.to_string();
+    } else {
+        if !path.ends_with("/") {
+            *path += "/";
+        }
+        *path += p;
+    }
+}
+
 type Error = gimli::Error;
 
 fn name_attr<'abbrev, 'unit, R>(