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elf: improve error reporting when resolving relocs
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@kubkon
kubkon committed Feb 26, 2024
1 parent b6ee748 commit f6f149f
Showing 1 changed file with 107 additions and 55 deletions.
162 changes: 107 additions & 55 deletions src/Elf/Atom.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -423,6 +423,7 @@ pub fn resolveRelocsAlloc(self: Atom, elf_file: *Elf, writer: anytype) !void {

var stream = std.io.fixedBufferStream(code);

var has_reloc_errors = false;
var it = RelocsIterator{ .relocs = relocs };
while (it.next()) |rel| {
const r_kind = relocation.decode(rel.r_type(), cpu_arch);
Expand Down Expand Up @@ -462,9 +463,18 @@ pub fn resolveRelocsAlloc(self: Atom, elf_file: *Elf, writer: anytype) !void {
const args = ResolveArgs{ P, A, S, GOT, G, TP, DTP };

switch (cpu_arch) {
.x86_64 => try x86_64.resolveRelocAlloc(self, elf_file, rel, target, args, &it, code, &stream),
.aarch64 => try aarch64.resolveRelocAlloc(self, elf_file, rel, target, args, &it, code, &stream),
.riscv64 => try riscv.resolveRelocAlloc(self, elf_file, rel, target, args, &it, code, &stream),
.x86_64 => x86_64.resolveRelocAlloc(self, elf_file, rel, target, args, &it, code, &stream) catch |err| switch (err) {
error.RelocError => has_reloc_errors = true,
else => |e| return e,
},
.aarch64 => aarch64.resolveRelocAlloc(self, elf_file, rel, target, args, &it, code, &stream) catch |err| switch (err) {
error.RelocError => has_reloc_errors = true,
else => |e| return e,
},
.riscv64 => riscv.resolveRelocAlloc(self, elf_file, rel, target, args, &it, code, &stream) catch |err| switch (err) {
error.RelocError => has_reloc_errors = true,
else => |e| return e,
},
else => |arch| {
elf_file.base.fatal("TODO support {s} architecture", .{@tagName(arch)});
return error.UnhandledCpuArch;
Expand All @@ -473,6 +483,8 @@ pub fn resolveRelocsAlloc(self: Atom, elf_file: *Elf, writer: anytype) !void {
}

try writer.writeAll(code);

if (has_reloc_errors) return error.RelocError;
}

fn resolveDynAbsReloc(
Expand Down Expand Up @@ -587,6 +599,7 @@ pub fn resolveRelocsNonAlloc(self: Atom, elf_file: *Elf, writer: anytype) !void

var stream = std.io.fixedBufferStream(code);

var has_reloc_errors = false;
var it = RelocsIterator{ .relocs = relocs };
while (it.next()) |rel| {
const r_kind = relocation.decode(rel.r_type(), cpu_arch);
Expand Down Expand Up @@ -614,9 +627,18 @@ pub fn resolveRelocsNonAlloc(self: Atom, elf_file: *Elf, writer: anytype) !void
const args = ResolveArgs{ 0, A, S, GOT, 0, 0, DTP };

switch (cpu_arch) {
.x86_64 => try x86_64.resolveRelocNonAlloc(self, elf_file, rel, target, args, &it, code, &stream),
.aarch64 => try aarch64.resolveRelocNonAlloc(self, elf_file, rel, target, args, &it, code, &stream),
.riscv64 => try riscv.resolveRelocNonAlloc(self, elf_file, rel, target, args, &it, code, &stream),
.x86_64 => x86_64.resolveRelocNonAlloc(self, elf_file, rel, target, args, &it, code, &stream) catch |err| switch (err) {
error.RelocError => has_reloc_errors = true,
else => |e| return e,
},
.aarch64 => aarch64.resolveRelocNonAlloc(self, elf_file, rel, target, args, &it, code, &stream) catch |err| switch (err) {
error.RelocError => has_reloc_errors = true,
else => |e| return e,
},
.riscv64 => riscv.resolveRelocNonAlloc(self, elf_file, rel, target, args, &it, code, &stream) catch |err| switch (err) {
error.RelocError => has_reloc_errors = true,
else => |e| return e,
},
else => |arch| {
elf_file.base.fatal("TODO support {s} architecture", .{@tagName(arch)});
return error.UnhandledCpuArch;
Expand All @@ -625,6 +647,8 @@ pub fn resolveRelocsNonAlloc(self: Atom, elf_file: *Elf, writer: anytype) !void
}

try writer.writeAll(code);

if (has_reloc_errors) return error.RelocError;
}

pub fn format(
Expand Down Expand Up @@ -934,9 +958,12 @@ const x86_64 = struct {
try cwriter.writeAll(&.{ 0x66, 0x90 });
},

else => elf_file.base.fatal("unhandled relocation type: {}", .{
relocation.fmtRelocType(rel.r_type(), .x86_64),
}),
else => {
elf_file.base.fatal("unhandled relocation type: {}", .{
relocation.fmtRelocType(rel.r_type(), .x86_64),
});
return error.RelocError;
},
}
}

Expand Down Expand Up @@ -981,10 +1008,13 @@ const x86_64 = struct {
const size = @as(i64, @intCast(target.getSourceSymbol(elf_file).st_size));
try cwriter.writeInt(i64, @as(i64, @intCast(size + A)), .little);
},
else => elf_file.base.fatal("{s}: invalid relocation type for non-alloc section: {}", .{
atom.getName(elf_file),
relocation.fmtRelocType(rel.r_type(), .x86_64),
}),
else => {
elf_file.base.fatal("{s}: invalid relocation type for non-alloc section: {}", .{
atom.getName(elf_file),
relocation.fmtRelocType(rel.r_type(), .x86_64),
});
return error.RelocError;
},
}
}

Expand Down Expand Up @@ -1035,10 +1065,13 @@ const x86_64 = struct {
try writer.writeAll(&insts);
},

else => elf_file.base.fatal("TODO rewrite {} when followed by {}", .{
relocation.fmtRelocType(rels[0].r_type(), .x86_64),
relocation.fmtRelocType(rels[1].r_type(), .x86_64),
}),
else => {
elf_file.base.fatal("TODO rewrite {} when followed by {}", .{
relocation.fmtRelocType(rels[0].r_type(), .x86_64),
relocation.fmtRelocType(rels[1].r_type(), .x86_64),
});
return error.RelocError;
},
}
}

Expand All @@ -1061,10 +1094,13 @@ const x86_64 = struct {
try writer.writeAll(&insts);
},

else => elf_file.base.fatal("TODO rewrite {} when followed by {}", .{
relocation.fmtRelocType(rels[0].r_type(), .x86_64),
relocation.fmtRelocType(rels[1].r_type(), .x86_64),
}),
else => {
elf_file.base.fatal("TODO rewrite {} when followed by {}", .{
relocation.fmtRelocType(rels[0].r_type(), .x86_64),
relocation.fmtRelocType(rels[1].r_type(), .x86_64),
});
return error.RelocError;
},
}
}

Expand Down Expand Up @@ -1100,10 +1136,13 @@ const x86_64 = struct {
try writer.writeAll(&insts);
},

else => elf_file.base.fatal("TODO rewrite {} when followed by {}", .{
relocation.fmtRelocType(rels[0].r_type(), .x86_64),
relocation.fmtRelocType(rels[1].r_type(), .x86_64),
}),
else => {
elf_file.base.fatal("TODO rewrite {} when followed by {}", .{
relocation.fmtRelocType(rels[0].r_type(), .x86_64),
relocation.fmtRelocType(rels[1].r_type(), .x86_64),
});
return error.RelocError;
},
}
}

Expand Down Expand Up @@ -1210,13 +1249,10 @@ const aarch64 = struct {
if (is_shared) try atom.picError(symbol, rel, elf_file);
},

.TLSDESC_ADR_PAGE21,
.TLSDESC_LD64_LO12,
.TLSDESC_ADD_LO12,
=> {
.TLSDESC_CALL => {
const should_relax = elf_file.options.static or
(elf_file.options.relax and !is_shared and !symbol.flags.import);
if (!should_relax and true) { // TODO
if (!should_relax) {
symbol.flags.tlsdesc = true;
}
},
Expand All @@ -1228,7 +1264,9 @@ const aarch64 = struct {
.LDST32_ABS_LO12_NC,
.LDST64_ABS_LO12_NC,
.LDST128_ABS_LO12_NC,
.TLSDESC_CALL,
.TLSDESC_ADR_PAGE21,
.TLSDESC_LD64_LO12,
.TLSDESC_ADD_LO12,
=> {},

else => {
Expand Down Expand Up @@ -1352,13 +1390,17 @@ const aarch64 = struct {
},

.TLSDESC_ADR_PAGE21 => {
assert(target.flags.tlsdesc); // TODO relax
const S_: i64 = @intCast(target.getTlsDescAddress(elf_file));
const saddr: u64 = @intCast(P);
const taddr: u64 = @intCast(S_ + A);
relocs_log.debug(" [{x} => {x}]", .{ P, taddr });
const pages: u21 = @bitCast(try aarch64_util.calcNumberOfPages(saddr, taddr));
aarch64_util.writeAdrpInst(pages, code[rel.r_offset..][0..4]);
if (target.flags.tlsdesc) {
const S_: i64 = @intCast(target.getTlsDescAddress(elf_file));
const saddr: u64 = @intCast(P);
const taddr: u64 = @intCast(S_ + A);
relocs_log.debug(" [{x} => {x}]", .{ P, taddr });
const pages: u21 = @bitCast(try aarch64_util.calcNumberOfPages(saddr, taddr));
aarch64_util.writeAdrpInst(pages, code[rel.r_offset..][0..4]);
} else {
elf_file.base.fatal("TODO relax TLSDESC sequence", .{});
return error.RelocError;
}
},

.TLSDESC_LD64_LO12 => {
Expand All @@ -1377,13 +1419,14 @@ const aarch64 = struct {
aarch64_util.writeAddImmInst(offset, code[rel.r_offset..][0..4]);
},

.TLSDESC_CALL => if (!target.flags.tlsdesc) {
mem.writeInt(u32, code[rel.r_offset..][0..4], aarch64_util.Instruction.nop().toU32(), .little);
},
.TLSDESC_CALL => {},

else => elf_file.base.fatal("unhandled relocation type: {}", .{
relocation.fmtRelocType(rel.r_type(), .aarch64),
}),
else => {
elf_file.base.fatal("unhandled relocation type: {}", .{
relocation.fmtRelocType(rel.r_type(), .aarch64),
});
return error.RelocError;
},
}
}

Expand Down Expand Up @@ -1414,10 +1457,13 @@ const aarch64 = struct {
.NONE => unreachable,
.ABS32 => try cwriter.writeInt(i32, @as(i32, @intCast(S + A)), .little),
.ABS64 => try cwriter.writeInt(i64, S + A, .little),
else => elf_file.base.fatal("{s}: invalid relocation type for non-alloc section: {}", .{
atom.getName(elf_file),
relocation.fmtRelocType(rel.r_type(), .aarch64),
}),
else => {
elf_file.base.fatal("{s}: invalid relocation type for non-alloc section: {}", .{
atom.getName(elf_file),
relocation.fmtRelocType(rel.r_type(), .aarch64),
});
return error.RelocError;
},
}
}

Expand Down Expand Up @@ -1578,9 +1624,12 @@ const riscv = struct {
}
},

else => elf_file.base.fatal("unhandled relocation type: {}", .{
relocation.fmtRelocType(rel.r_type(), .riscv64),
}),
else => {
elf_file.base.fatal("unhandled relocation type: {}", .{
relocation.fmtRelocType(rel.r_type(), .riscv64),
});
return error.RelocError;
},
}
}

Expand Down Expand Up @@ -1630,10 +1679,13 @@ const riscv = struct {
.SET6 => riscv_util.writeSetSub6(.set, code[rel.r_offset..][0..1], S + A),
.SUB6 => riscv_util.writeSetSub6(.sub, code[rel.r_offset..][0..1], S + A),

else => elf_file.base.fatal("{s}: invalid relocation type for non-alloc section: {}", .{
atom.getName(elf_file),
relocation.fmtRelocType(rel.r_type(), .riscv64),
}),
else => {
elf_file.base.fatal("{s}: invalid relocation type for non-alloc section: {}", .{
atom.getName(elf_file),
relocation.fmtRelocType(rel.r_type(), .riscv64),
});
return error.RelocError;
},
}
}

Expand Down

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