fixathon added inline comments.
================
Comment at: lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp:540
+ for (uint32_t i = 0;
+ count > 0 && count <= sizeof(gpr.r) && i < count - 1; ++i) {
gpr.r[i] = data.GetU32(&offset);
----------------
jasonmolenda wrote:
> jasonmolenda wrote:
> > The `count` field for a Darwin register context is the number of 4-byte
> > entries in the object - it's a trick the kernel API often use so they can
> > add fields later and the kernel knows what version of the object the
> > userland process is requesting when it asks for "flavor, size" in a
> > `get_thread_state` call. This Aarch32 register context is `struct GPR
> > {uint32_t r[16]; uint32_t cpsr};` or count 17, but `sizeof(gpr.r)` is going
> > to be 64. We only want to loop for 16 entries.
> FWIW the Aarch64 version of this function hardcodes the number of elements
> (where each general purpose register is 8-bytes, so count==2, and then
> there's one cpsr 4-byte register),
> ```
> // x0-x29 + fp + lr + sp + pc (== 33 64-bit registers) plus cpsr (1
> // 32-bit register)
> if (count >= (33 * 2) + 1) {
> for (uint32_t i = 0; i < 29; ++i)
> gpr.x[i] = data.GetU64(&offset);
> gpr.fp = data.GetU64(&offset);
> gpr.lr = data.GetU64(&offset);
> gpr.sp = data.GetU64(&offset);
> gpr.pc = data.GetU64(&offset);
> gpr.cpsr = data.GetU32(&offset);
> ```
Good catch. I'll: count <= sizeof(gpr.r)/sizeof(gpr.r[0])
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D131554/new/
https://reviews.llvm.org/D131554
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