authorgravatar for alex@alexrp.comAlex Rønne Petersen <alex@alexrp.com> 2024-08-13 02:03:42+02:00
committergravatar for alex@alexrp.comAlex Rønne Petersen <alex@alexrp.com> 2024-08-15 10:56:33+02:00
log2bf244c0e92a02dbd260057332663aae61852712
tree86b4a0c3f33fd490616a6b12db86bb9f17513f9c
parentab9628dd2c7441e2cc648874583cc38a357998a1
signaturebadge-check Signed by SSH key SHA256:7B/LJ7bpR1eX8aCXSr4mtd5M45VMPKcx9zY8e95b5QM

llvm: Always omit the frame pointer for naked functions.

1 files changed, 16 insertions(+), 5 deletions(-)

src/codegen/llvm.zig+16-5
......@@ -2909,7 +2909,17 @@ pub const Object = struct {
29092909 function_index.setAlignment(resolved.alignment.toLlvm(), &o.builder);
29102910
29112911 // Function attributes that are independent of analysis results of the function body.
2912 try o.addCommonFnAttributes(&attributes, owner_mod);
2912 try o.addCommonFnAttributes(
2913 &attributes,
2914 owner_mod,
2915 // Some backends don't respect the `naked` attribute in `TargetFrameLowering::hasFP()`,
2916 // so for these backends, LLVM will happily emit code that accesses the stack through
2917 // the frame pointer. This is nonsensical since what the `naked` attribute does is
2918 // suppress generation of the prologue and epilogue, and the prologue is where the
2919 // frame pointer normally gets set up. At time of writing, this is the case for at
2920 // least x86 and RISC-V.
2921 owner_mod.omit_frame_pointer or fn_info.cc == .Naked,
2922 );
29132923
29142924 if (fn_info.return_type == .noreturn_type) try attributes.addFnAttr(.noreturn, &o.builder);
29152925
......@@ -2956,13 +2966,14 @@ pub const Object = struct {
29562966 o: *Object,
29572967 attributes: *Builder.FunctionAttributes.Wip,
29582968 owner_mod: *Package.Module,
2969 omit_frame_pointer: bool,
29592970 ) Allocator.Error!void {
29602971 const comp = o.pt.zcu.comp;
29612972
29622973 if (!owner_mod.red_zone) {
29632974 try attributes.addFnAttr(.noredzone, &o.builder);
29642975 }
2965 if (owner_mod.omit_frame_pointer) {
2976 if (omit_frame_pointer) {
29662977 try attributes.addFnAttr(.{ .string = .{
29672978 .kind = try o.builder.string("frame-pointer"),
29682979 .value = try o.builder.string("none"),
......@@ -4528,7 +4539,7 @@ pub const Object = struct {
45284539
45294540 var attributes: Builder.FunctionAttributes.Wip = .{};
45304541 defer attributes.deinit(&o.builder);
4531 try o.addCommonFnAttributes(&attributes, zcu.root_mod);
4542 try o.addCommonFnAttributes(&attributes, zcu.root_mod, zcu.root_mod.omit_frame_pointer);
45324543
45334544 function_index.setLinkage(.internal, &o.builder);
45344545 function_index.setCallConv(.fastcc, &o.builder);
......@@ -4557,7 +4568,7 @@ pub const Object = struct {
45574568
45584569 var attributes: Builder.FunctionAttributes.Wip = .{};
45594570 defer attributes.deinit(&o.builder);
4560 try o.addCommonFnAttributes(&attributes, zcu.root_mod);
4571 try o.addCommonFnAttributes(&attributes, zcu.root_mod, zcu.root_mod.omit_frame_pointer);
45614572
45624573 function_index.setLinkage(.internal, &o.builder);
45634574 function_index.setCallConv(.fastcc, &o.builder);
......@@ -9676,7 +9687,7 @@ pub const FuncGen = struct {
96769687
96779688 var attributes: Builder.FunctionAttributes.Wip = .{};
96789689 defer attributes.deinit(&o.builder);
9679 try o.addCommonFnAttributes(&attributes, zcu.root_mod);
9690 try o.addCommonFnAttributes(&attributes, zcu.root_mod, zcu.root_mod.omit_frame_pointer);
96809691
96819692 function_index.setLinkage(.internal, &o.builder);
96829693 function_index.setCallConv(.fastcc, &o.builder);