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Fix fp-based backtracing on RISC-V

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The fp points to the top of the frame instead of pointing to the old fp,
compensate this difference with an offset.
This commit is contained in:
LemonBoy 2019-10-13 12:13:41 +02:00
parent ba711f1115
commit b1f3f59d66
1 changed files with 15 additions and 6 deletions
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21
lib/std/debug.zig
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@ -280,14 +280,23 @@ pub const StackIterator = struct {
};
}
// On some architectures such as x86 the frame pointer is the address where
// the previous fp is stored, while on some other architectures such as
// RISC-V it points to the "top" of the frame, just above where the previous
// fp and the return address are stored.
const fp_adjust_factor = if (builtin.arch == .riscv32 or builtin.arch == .riscv64)
2 * @sizeOf(usize)
else
0;
fn next(self: *StackIterator) ?usize {
if (self.fp == 0) return null;
self.fp = @intToPtr(*const usize, self.fp).*;
if (self.fp == 0) return null;
if (self.fp < fp_adjust_factor) return null;
self.fp = @intToPtr(*const usize, self.fp - fp_adjust_factor).*;
if (self.fp < fp_adjust_factor) return null;
if (self.first_addr) |addr| {
while (self.fp != 0) : (self.fp = @intToPtr(*const usize, self.fp).*) {
const return_address = @intToPtr(*const usize, self.fp + @sizeOf(usize)).*;
while (self.fp >= fp_adjust_factor) : (self.fp = @intToPtr(*const usize, self.fp - fp_adjust_factor).*) {
const return_address = @intToPtr(*const usize, self.fp - fp_adjust_factor + @sizeOf(usize)).*;
if (addr == return_address) {
self.first_addr = null;
return return_address;
@ -295,7 +304,7 @@ pub const StackIterator = struct {
}
}
const return_address = @intToPtr(*const usize, self.fp + @sizeOf(usize)).*;
const return_address = @intToPtr(*const usize, self.fp - fp_adjust_factor + @sizeOf(usize)).*;
return return_address;
}
};