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stage2: fix memory leak of emit_bin.sub_path

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Instead of juggling GPA-allocated sub_path (and ultimately dropping the
ball, in this analogy), `Compilation.create` allocates an
already-exactly-correct size `sub_path` that has the digest unpopulated.

This is then overwritten in place as necessary and used as the
`emit_bin.sub_path` value, and no allocations/frees are performed for
this file path.
This commit is contained in:
Andrew Kelley 2021-12-30 21:28:56 -07:00
parent 208a6c7d6a
commit 73ba6bf30b
1 changed files with 28 additions and 32 deletions
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60
src/Compilation.zig
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@ -98,9 +98,11 @@ clang_argv: []const []const u8,
cache_parent: *Cache,
/// Path to own executable for invoking `zig clang`.
self_exe_path: ?[]const u8,
/// null means -fno-emit-bin. Contains the basename of the
/// outputted binary file in case we don't know the directory yet.
whole_bin_basename: ?[]const u8,
/// null means -fno-emit-bin.
/// This is mutable memory allocated into the Compilation-lifetime arena (`arena_state`)
/// of exactly the correct size for "o/[digest]/[basename]".
/// The basename is of the outputted binary file in case we don't know the directory yet.
whole_bin_sub_path: ?[]u8,
zig_lib_directory: Directory,
local_cache_directory: Directory,
global_cache_directory: Directory,
@ -1487,9 +1489,12 @@ pub fn create(gpa: Allocator, options: InitOptions) !*Compilation {
// can use it for communicating the result directory via `bin_file.emit`.
// This is used to distinguish between -fno-emit-bin and -femit-bin
// for `CacheMode.whole`.
const whole_bin_basename: ?[]const u8 = if (options.emit_bin) |x|
// This memory will be overwritten with the real digest in update() but
// the basename will be preserved.
const whole_bin_sub_path: ?[]u8 = if (options.emit_bin) |x|
if (x.directory == null)
x.basename
try std.fmt.allocPrint(arena, "o" ++ std.fs.path.sep_str ++
("x" ** Cache.hex_digest_len) ++ std.fs.path.sep_str ++ "{s}", .{x.basename})
else
null
else
@ -1600,7 +1605,7 @@ pub fn create(gpa: Allocator, options: InitOptions) !*Compilation {
.local_cache_directory = options.local_cache_directory,
.global_cache_directory = options.global_cache_directory,
.bin_file = bin_file,
.whole_bin_basename = whole_bin_basename,
.whole_bin_sub_path = whole_bin_sub_path,
.emit_asm = options.emit_asm,
.emit_llvm_ir = options.emit_llvm_ir,
.emit_llvm_bc = options.emit_llvm_bc,
@ -1665,7 +1670,7 @@ pub fn create(gpa: Allocator, options: InitOptions) !*Compilation {
comp.c_object_table.putAssumeCapacityNoClobber(c_object, {});
}
const have_bin_emit = comp.bin_file.options.emit != null or comp.whole_bin_basename != null;
const have_bin_emit = comp.bin_file.options.emit != null or comp.whole_bin_sub_path != null;
if (have_bin_emit and !comp.bin_file.options.skip_linker_dependencies) {
// If we need to build glibc for the target, add work items for it.
@ -1941,19 +1946,7 @@ pub fn update(comp: *Compilation) !void {
log.debug("CacheMode.whole cache hit for {s}", .{comp.bin_file.options.root_name});
const digest = man.final();
// Communicate the output binary location to parent Compilations.
if (comp.whole_bin_basename) |basename| {
const new_sub_path = try std.fs.path.join(comp.gpa, &.{
"o", &digest, basename,
});
if (comp.bin_file.options.emit) |emit| {
comp.gpa.free(emit.sub_path);
}
comp.bin_file.options.emit = .{
.directory = comp.local_cache_directory,
.sub_path = new_sub_path,
};
}
comp.wholeCacheModeSetBinFilePath(&digest);
assert(comp.bin_file.lock == null);
comp.bin_file.lock = man.toOwnedLock();
@ -1989,13 +1982,10 @@ pub fn update(comp: *Compilation) !void {
// This resets the link.File to operate as if we called openPath() in create()
// instead of simulating -fno-emit-bin.
var options = comp.bin_file.options;
if (comp.whole_bin_basename) |basename| {
if (options.emit) |emit| {
comp.gpa.free(emit.sub_path);
}
if (comp.whole_bin_sub_path) |sub_path| {
options.emit = .{
.directory = tmp_artifact_directory.?,
.sub_path = basename,
.sub_path = std.fs.path.basename(sub_path),
};
}
comp.bin_file.destroy();
@ -2149,13 +2139,7 @@ pub fn update(comp: *Compilation) !void {
log.warn("failed to write cache manifest: {s}", .{@errorName(err)});
};
// Communicate the output binary location to parent Compilations.
if (comp.whole_bin_basename) |basename| {
comp.bin_file.options.emit = .{
.directory = comp.local_cache_directory,
.sub_path = try std.fs.path.join(comp.gpa, &.{ "o", &digest, basename }),
};
}
comp.wholeCacheModeSetBinFilePath(&digest);
assert(comp.bin_file.lock == null);
comp.bin_file.lock = man.toOwnedLock();
@ -2163,6 +2147,18 @@ pub fn update(comp: *Compilation) !void {
}
}
/// Communicate the output binary location to parent Compilations.
fn wholeCacheModeSetBinFilePath(comp: *Compilation, digest: *const [Cache.hex_digest_len]u8) void {
const sub_path = comp.whole_bin_sub_path orelse return;
const digest_start = 2; // "o/[digest]/[basename]"
mem.copy(u8, sub_path[digest_start..], digest);
comp.bin_file.options.emit = .{
.directory = comp.local_cache_directory,
.sub_path = sub_path,
};
}
/// This is only observed at compile-time and used to emit a compile error
/// to remind the programmer to update multiple related pieces of code that
/// are in different locations. Bump this number when adding or deleting