[Lldb-commits] [lldb] [lldb][debugserver] Read/write SME registers on arm64 (PR #119171)

[David Spickett via lldb-commits]

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@@ -312,16 +312,21 @@ struct DNBRegisterValue {
     uint64_t uint64;
     float float32;
     double float64;
-    int8_t v_sint8[64];
-    int16_t v_sint16[32];
-    int32_t v_sint32[16];
-    int64_t v_sint64[8];
-    uint8_t v_uint8[64];
-    uint16_t v_uint16[32];
-    uint32_t v_uint32[16];
-    uint64_t v_uint64[8];
-    float v_float32[16];
-    double v_float64[8];
+    // AArch64 SME's ZA register max size is 64k, this object must be
+    // large enough to hold that much data.  The current Apple cores
+    // have a much smaller maximum ZA reg size, but there are not
+    // multiple copies of this object so increase the static size to
+    // maximum possible.
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DavidSpickett wrote:

I think for Linux we were also stack allocating the register value and I didn't want 64k stack frames everywhere we used one. https://github.com/llvm/llvm-project/commit/d99d9d8b74ffcb8ac418fcdafa750b07f2bd9935 in case any of the concerns apply to debugserver also.

(I am also very aware of these issues because in a previous job when we added MIPS MSA support we accidentally turned every register object into 512 bits, even the 8 and 16 bit ones we read from non-MIPS DSP chips)

https://github.com/llvm/llvm-project/pull/119171