Add DWARF unwinding, and an external debug info loader for ELF

lib/std/c.zig

@@ -413,6 +413,13 @@ pub extern "c" fn timer_delete(timerid: c.timer_t) c_int;
 pub extern "c" fn timer_settime(timerid: c.timer_t, flags: c_int, new_value: *const c.itimerspec, old_value: *c.itimerspec) c_int;
 pub extern "c" fn timer_gettime(timerid: c.timer_t, flags: c_int, curr_value: *c.itimerspec) c_int;
 
+pub usingnamespace if (builtin.os.tag == .linux and builtin.target.isMusl()) struct {
+    // musl does not implement getcontext
+    pub const getcontext = std.os.linux.getcontext;
+} else struct {
+    pub extern "c" fn getcontext(ucp: *std.os.ucontext_t) c_int;
+};
+
 pub const max_align_t = if (builtin.abi == .msvc)
     f64
 else if (builtin.target.isDarwin())

lib/std/c/darwin.zig

@@ -148,12 +148,10 @@ pub const ucontext_t = extern struct {
     link: ?*ucontext_t,
     mcsize: u64,
     mcontext: *mcontext_t,
+    __mcontext_data: mcontext_t,
 };
 
-pub const mcontext_t = extern struct {
-    es: arch_bits.exception_state,
-    ss: arch_bits.thread_state,
-};
+pub const mcontext_t = arch_bits.mcontext_t;
 
 extern "c" fn __error() *c_int;
 pub extern "c" fn NSVersionOfRunTimeLibrary(library_name: [*:0]const u8) u32;

lib/std/c/darwin/aarch64.zig

@@ -1,5 +1,12 @@
 // See C headers in
 // lib/libc/include/aarch64-macos.12-gnu/mach/arm/_structs.h
+// lib/libc/include/aarch64-macos.13-none/arm/_mcontext.h
+
+pub const mcontext_t = extern struct {
+    es: exception_state,
+    ss: thread_state,
+    ns: neon_state,
+};
 
 pub const exception_state = extern struct {
     far: u64, // Virtual Fault Address
@@ -17,6 +24,12 @@ pub const thread_state = extern struct {
     __pad: u32,
 };
 
+pub const neon_state = extern struct {
+    q: [32]u128,
+    fpsr: u32,
+    fpcr: u32,
+};
+
 pub const EXC_TYPES_COUNT = 14;
 pub const EXC_MASK_MACHINE = 0;
 

lib/std/c/darwin/x86_64.zig

@@ -1,5 +1,11 @@
 const c = @import("../darwin.zig");
 
+pub const mcontext_t = extern struct {
+    es: exception_state,
+    ss: thread_state,
+    fs: float_state,
+};
+
 pub const exception_state = extern struct {
     trapno: u16,
     cpu: u16,
@@ -31,6 +37,29 @@ pub const thread_state = extern struct {
     gs: u64,
 };
 
+const stmm_reg = [16]u8;
+const xmm_reg = [16]u8;
+pub const float_state = extern struct {
+    reserved: [2]c_int,
+    fcw: u16,
+    fsw: u16,
+    ftw: u8,
+    rsrv1: u8,
+    fop: u16,
+    ip: u32,
+    cs: u16,
+    rsrv2: u16,
+    dp: u32,
+    ds: u16,
+    rsrv3: u16,
+    mxcsr: u32,
+    mxcsrmask: u32,
+    stmm: [8]stmm_reg,
+    xmm: [16]xmm_reg,
+    rsrv4: [96]u8,
+    reserved1: c_int,
+};
+
 pub const THREAD_STATE = 4;
 pub const THREAD_STATE_COUNT: c.mach_msg_type_number_t = @sizeOf(thread_state) / @sizeOf(c_int);
 

lib/std/coff.zig

@@ -1214,6 +1214,11 @@ pub const Coff = struct {
         return Strtab{ .buffer = self.data[offset..][0..size] };
     }
 
+    pub fn strtabRequired(self: *const Coff) bool {
+        for (self.getSectionHeaders()) |*sect_hdr| if (sect_hdr.getName() == null) return true;
+        return false;
+    }
+
     pub fn getSectionHeaders(self: *const Coff) []align(1) const SectionHeader {
         const coff_header = self.getCoffHeader();
         const offset = self.coff_header_offset + @sizeOf(CoffHeader) + coff_header.size_of_optional_header;
@@ -1248,14 +1253,12 @@ pub const Coff = struct {
         return null;
     }
 
-    pub fn getSectionData(self: *const Coff, comptime name: []const u8) ![]const u8 {
-        const sec = self.getSectionByName(name) orelse return error.MissingCoffSection;
+    pub fn getSectionData(self: *const Coff, sec: *align(1) const SectionHeader) []const u8 {
         return self.data[sec.pointer_to_raw_data..][0..sec.virtual_size];
     }
 
-    // Return an owned slice full of the section data
-    pub fn getSectionDataAlloc(self: *const Coff, comptime name: []const u8, allocator: mem.Allocator) ![]u8 {
-        const section_data = try self.getSectionData(name);
+    pub fn getSectionDataAlloc(self: *const Coff, sec: *align(1) const SectionHeader, allocator: mem.Allocator) ![]u8 {
+        const section_data = self.getSectionData(sec);
         return allocator.dupe(u8, section_data);
     }
 };