fixathon marked 2 inline comments as done.
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);
----------------
fixathon wrote:
> jasonmolenda wrote:
> > jasonmolenda wrote:
> > > clayborg 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])
"count > 0 && count <= sizeof(gpr.r)/sizeof(uint32_t) && i < count - 1; ++i)"
was causing a compiler warning, which is the reason I moved **count** out of
the for loop condition
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D131554/new/
https://reviews.llvm.org/D131554
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