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stage1: deal with WebAssembly not supporting @returnAddress()

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This makes `@returnAddress()` return 0 for WebAssembly (when not using
the Emscripten OS) and avoids trying to capture stack traces for the
general purpose allocator on that target.
This commit is contained in:
Andrew Kelley 2020-08-08 01:00:29 -07:00
parent 9f5a7d5922
commit 1b1921f0e2
3 changed files with 19 additions and 3 deletions
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11
lib/std/heap.zig
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@ -37,7 +37,7 @@ var c_allocator_state = Allocator{
.resizeFn = cResize, .resizeFn = cResize,
}; };
fn cAlloc(self: *Allocator, len: usize, ptr_align: u29, len_align: u29) Allocator.Error![]u8 { fn cAlloc(self: *Allocator, len: usize, ptr_align: u29, len_align: u29, ret_addr: usize) Allocator.Error![]u8 {
assert(ptr_align <= @alignOf(c_longdouble)); assert(ptr_align <= @alignOf(c_longdouble));
const ptr = @ptrCast([*]u8, c.malloc(len) orelse return error.OutOfMemory); const ptr = @ptrCast([*]u8, c.malloc(len) orelse return error.OutOfMemory);
if (len_align == 0) { if (len_align == 0) {
@ -54,7 +54,14 @@ fn cAlloc(self: *Allocator, len: usize, ptr_align: u29, len_align: u29) Allocato
return ptr[0..mem.alignBackwardAnyAlign(full_len, len_align)]; return ptr[0..mem.alignBackwardAnyAlign(full_len, len_align)];
} }
fn cResize(self: *Allocator, buf: []u8, old_align: u29, new_len: usize, len_align: u29) Allocator.Error!usize { fn cResize(
self: *Allocator,
buf: []u8,
old_align: u29,
new_len: usize,
len_align: u29,
ret_addr: usize,
) Allocator.Error!usize {
if (new_len == 0) { if (new_len == 0) {
c.free(buf.ptr); c.free(buf.ptr);
return 0; return 0;

5
lib/std/heap/general_purpose_allocator.zig
View File

@ -102,9 +102,12 @@ const StackTrace = std.builtin.StackTrace;
/// Integer type for pointing to slots in a small allocation /// Integer type for pointing to slots in a small allocation
const SlotIndex = std.meta.Int(false, math.log2(page_size) + 1); const SlotIndex = std.meta.Int(false, math.log2(page_size) + 1);
// WebAssembly doesn't support stack tracing yet.
const default_stack_trace_frames: usize = if (std.Target.current.cpu.arch.isWasm()) 0 else 4;
pub const Config = struct { pub const Config = struct {
/// Number of stack frames to capture. /// Number of stack frames to capture.
stack_trace_frames: usize = if (std.debug.runtime_safety) @as(usize, 4) else @as(usize, 0), stack_trace_frames: usize = if (std.debug.runtime_safety) default_stack_trace_frames else @as(usize, 0),
/// If true, the allocator will have two fields: /// If true, the allocator will have two fields:
/// * `total_requested_bytes` which tracks the total allocated bytes of memory requested. /// * `total_requested_bytes` which tracks the total allocated bytes of memory requested.

6
src/codegen.cpp
View File

@ -5886,6 +5886,12 @@ static LLVMValueRef ir_render_breakpoint(CodeGen *g, IrExecutableGen *executable
static LLVMValueRef ir_render_return_address(CodeGen *g, IrExecutableGen *executable, static LLVMValueRef ir_render_return_address(CodeGen *g, IrExecutableGen *executable,
IrInstGenReturnAddress *instruction) IrInstGenReturnAddress *instruction)
{ {
if (target_is_wasm(g->zig_target) && g->zig_target->os != OsEmscripten) {
// I got this error from LLVM 10:
// "Non-Emscripten WebAssembly hasn't implemented __builtin_return_address"
return LLVMConstNull(get_llvm_type(g, instruction->base.value->type));
}
LLVMValueRef zero = LLVMConstNull(g->builtin_types.entry_i32->llvm_type); LLVMValueRef zero = LLVMConstNull(g->builtin_types.entry_i32->llvm_type);
LLVMValueRef ptr_val = LLVMBuildCall(g->builder, get_return_address_fn_val(g), &zero, 1, ""); LLVMValueRef ptr_val = LLVMBuildCall(g->builder, get_return_address_fn_val(g), &zero, 1, "");
return LLVMBuildPtrToInt(g->builder, ptr_val, g->builtin_types.entry_usize->llvm_type, ""); return LLVMBuildPtrToInt(g->builder, ptr_val, g->builtin_types.entry_usize->llvm_type, "");