motiejus/zig

commit 5c7f2ab011f9c1cd522ab76a674d0acc5f397041 (tree)
parent 16b753549702e2fc662491a468dd3323e8a51042
Author: Kenta Iwasaki <kenta@lithdew.net>
Date:   Mon, 20 Dec 2021 00:30:49 +0900

stage1: deal with BPF not supporting @returnAddress()

Make `@returnAddress()` return for the BPF target, as the BPF target for
the time being does not support probing for the return address. Stack
traces for the general purpose allocator for the BPF target is also set
to not be captured.

Diffstat:
M
lib/std/heap/general_purpose_allocator.zig
 | 
5
+++++
M
src/stage1/codegen.cpp
 | 
2
+-
M
src/stage1/target.cpp
 | 
4
++++
M
src/stage1/target.hpp
 | 
1
+

4 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/lib/std/heap/general_purpose_allocator.zig b/lib/std/heap/general_purpose_allocator.zig
@@ -118,6 +118,11 @@ const sys_can_stack_trace = switch (builtin.cpu.arch) {
     .wasm64,
     => builtin.os.tag == .emscripten,
 
+    // `@returnAddress()` is unsupported in LLVM 13.
+    .bpfel,
+    .bpfeb,
+    => false,
+
     else => true,
 };
 const default_test_stack_trace_frames: usize = if (builtin.is_test) 8 else 4;
diff --git a/src/stage1/codegen.cpp b/src/stage1/codegen.cpp
@@ -6208,7 +6208,7 @@ static LLVMValueRef ir_render_breakpoint(CodeGen *g, Stage1Air *executable, Stag
 static LLVMValueRef ir_render_return_address(CodeGen *g, Stage1Air *executable,
         Stage1AirInstReturnAddress *instruction)
 {
-    if (target_is_wasm(g->zig_target) && g->zig_target->os != OsEmscripten) {
+    if ((target_is_wasm(g->zig_target) && g->zig_target->os != OsEmscripten) || target_is_bpf(g->zig_target)) {
         // 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));
diff --git a/src/stage1/target.cpp b/src/stage1/target.cpp
@@ -940,6 +940,10 @@ bool target_is_wasm(const ZigTarget *target) {
     return target->arch == ZigLLVM_wasm32 || target->arch == ZigLLVM_wasm64;
 }
 
+bool target_is_bpf(const ZigTarget *target) {
+    return target->arch == ZigLLVM_bpfel || target->arch == ZigLLVM_bpfeb;
+}
+
 ZigLLVM_EnvironmentType target_default_abi(ZigLLVM_ArchType arch, Os os) {
     if (arch == ZigLLVM_wasm32 || arch == ZigLLVM_wasm64) {
         return ZigLLVM_Musl;
diff --git a/src/stage1/target.hpp b/src/stage1/target.hpp
@@ -75,6 +75,7 @@ bool target_allows_addr_zero(const ZigTarget *target);
 bool target_has_valgrind_support(const ZigTarget *target);
 bool target_os_is_darwin(Os os);
 bool target_is_wasm(const ZigTarget *target);
+bool target_is_bpf(const ZigTarget *target);
 bool target_is_riscv(const ZigTarget *target);
 bool target_is_sparc(const ZigTarget *target);
 bool target_is_android(const ZigTarget *target);