Auto merge of #28242 - Diggsey:msvc-backtrace, r=alexcrichton

Currently LLVM does not generate the debug info required to get complete backtraces even when functions are inlined, so that part of the `run-pass/backtrace-debuginfo.rs` test is disabled when targetting MSVC. At worst this results in missing stack frames where functions have been inlined.

Author: bors

src/libstd/sys/windows/backtrace.rs

@@ -60,6 +60,9 @@ extern "system" {
 type SymFromAddrFn =
     extern "system" fn(libc::HANDLE, u64, *mut u64,
                        *mut SYMBOL_INFO) -> libc::BOOL;
+type SymGetLineFromAddr64Fn =
+    extern "system" fn(libc::HANDLE, u64, *mut u32,
+                       *mut IMAGEHLP_LINE64) -> libc::BOOL;
 type SymInitializeFn =
     extern "system" fn(libc::HANDLE, *mut libc::c_void,
                        libc::BOOL) -> libc::BOOL;
@@ -99,6 +102,14 @@ struct SYMBOL_INFO {
     Name: [libc::c_char; MAX_SYM_NAME],
 }
 
+#[repr(C)]
+struct IMAGEHLP_LINE64 {
+    SizeOfStruct: u32,
+    Key: *const libc::c_void,
+    LineNumber: u32,
+    Filename: *const libc::c_char,
+    Address: u64,
+}
 
 #[repr(C)]
 enum ADDRESS_MODE {

src/libstd/sys/windows/printing/msvc.rs

@@ -8,10 +8,10 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use sys_common::backtrace::output;
+use sys_common::backtrace::{output, output_fileline};
 use ffi::CStr;
 use dynamic_lib::DynamicLibrary;
-use super::{SymFromAddrFn, SYMBOL_INFO, MAX_SYM_NAME};
+use super::{SymFromAddrFn, SymGetLineFromAddr64Fn, SYMBOL_INFO, MAX_SYM_NAME, IMAGEHLP_LINE64};
 use io;
 use io::prelude::*;
 use intrinsics;
@@ -20,6 +20,7 @@ use libc;
 pub fn print(w: &mut Write, i: isize, addr: u64, dbghelp: &DynamicLibrary, process: libc::HANDLE)
         -> io::Result<()> {
     let SymFromAddr = sym!(dbghelp, "SymFromAddr", SymFromAddrFn);
+    let SymGetLineFromAddr64 = sym!(dbghelp, "SymGetLineFromAddr64", SymGetLineFromAddr64Fn);
 
     let mut info: SYMBOL_INFO = unsafe { intrinsics::init() };
     info.MaxNameLen = MAX_SYM_NAME as libc::c_ulong;
@@ -29,7 +30,7 @@ pub fn print(w: &mut Write, i: isize, addr: u64, dbghelp: &DynamicLibrary, proce
     info.SizeOfStruct = 88;
 
     let mut displacement = 0u64;
-    let ret = SymFromAddr(process, addr as u64, &mut displacement, &mut info);
+    let ret = SymFromAddr(process, addr, &mut displacement, &mut info);
 
     let name = if ret == libc::TRUE {
         let ptr = info.Name.as_ptr() as *const libc::c_char;
@@ -38,5 +39,20 @@ pub fn print(w: &mut Write, i: isize, addr: u64, dbghelp: &DynamicLibrary, proce
         None
     };
 
-    output(w, i, addr as usize as *mut libc::c_void, name)
+    try!(output(w, i, addr as usize as *mut libc::c_void, name));
+
+    // Now find out the filename and line number
+    let mut line: IMAGEHLP_LINE64 = unsafe { intrinsics::init() };
+    line.SizeOfStruct = ::mem::size_of::<IMAGEHLP_LINE64>() as u32;
+
+    let mut displacement = 0u32;
+    let ret = SymGetLineFromAddr64(process, addr, &mut displacement, &mut line);
+    if ret == libc::TRUE {
+        output_fileline(w,
+                        unsafe { CStr::from_ptr(line.Filename).to_bytes() },
+                        line.LineNumber as libc::c_int,
+                        false)
+    } else {
+        Ok(())
+    }
 }

src/test/run-pass/backtrace-debuginfo-aux.rs

@@ -15,7 +15,11 @@ pub fn callback<F>(f: F) where F: FnOnce((&'static str, u32)) {
     f((file!(), line!()))
 }
 
-#[inline(always)]
+// LLVM does not yet output the required debug info to support showing inlined
+// function calls in backtraces when targetting MSVC, so disable inlining in
+// this case.
+#[cfg_attr(not(target_env = "msvc"), inline(always))]
+#[cfg_attr(target_env = "msvc", inline(never))]
 pub fn callback_inlined<F>(f: F) where F: FnOnce((&'static str, u32)) {
     f((file!(), line!()))
 }

src/test/run-pass/backtrace-debuginfo.rs

@@ -32,7 +32,7 @@ macro_rules! pos {
               not(target_os = "ios"),
               not(target_os = "android"),
               not(all(target_os = "linux", target_arch = "arm"))),
-          all(windows, target_env = "gnu", not(target_arch = "x86"))))]
+          all(windows, not(target_arch = "x86"))))]
 macro_rules! dump_and_die {
     ($($pos:expr),*) => ({
         // FIXME(#18285): we cannot include the current position because
@@ -48,7 +48,7 @@ macro_rules! dump_and_die {
               not(target_os = "ios"),
               not(target_os = "android"),
               not(all(target_os = "linux", target_arch = "arm"))),
-          all(windows, target_env = "gnu", not(target_arch = "x86")))))]
+          all(windows, not(target_arch = "x86")))))]
 macro_rules! dump_and_die {
     ($($pos:expr),*) => ({ let _ = [$($pos),*]; })
 }
@@ -69,7 +69,10 @@ type Pos = (&'static str, u32);
 // this goes to stdout and each line has to be occurred
 // in the following backtrace to stderr with a correct order.
 fn dump_filelines(filelines: &[Pos]) {
-    for &(file, line) in filelines.iter().rev() {
+    // Skip top frame for MSVC, because it sees the macro rather than
+    // the containing function.
+    let skip = if cfg!(target_env = "msvc") {1} else {0};
+    for &(file, line) in filelines.iter().rev().skip(skip) {
         // extract a basename
         let basename = file.split(&['/', '\\'][..]).last().unwrap();
         println!("{}:{}", basename, line);
@@ -88,12 +91,18 @@ fn inner(counter: &mut i32, main_pos: Pos, outer_pos: Pos) {
     });
 }
 
-#[inline(always)]
+// LLVM does not yet output the required debug info to support showing inlined
+// function calls in backtraces when targetting MSVC, so disable inlining in
+// this case.
+#[cfg_attr(not(target_env = "msvc"), inline(always))]
+#[cfg_attr(target_env = "msvc", inline(never))]
 fn inner_inlined(counter: &mut i32, main_pos: Pos, outer_pos: Pos) {
     check!(counter; main_pos, outer_pos);
     check!(counter; main_pos, outer_pos);
 
-    #[inline(always)]
+    // Again, disable inlining for MSVC.
+    #[cfg_attr(not(target_env = "msvc"), inline(always))]
+    #[cfg_attr(target_env = "msvc", inline(never))]
     fn inner_further_inlined(counter: &mut i32, main_pos: Pos, outer_pos: Pos, inner_pos: Pos) {
         check!(counter; main_pos, outer_pos, inner_pos);
     }