From ddf1b46ba96686710ee7e8942acef3af15db928e Mon Sep 17 00:00:00 2001
From: Jack Gallagher <jack.gallagher@arm.com>
Date: Wed, 14 Feb 2024 13:09:33 +0100
Subject: [PATCH] i#5365 AArch64: Fix tests on non 256-bit VL hardware

Some of the SVE tests are written assuming a 256-bit vector length so
that we get consistent output from the codec regardless of the hardware
vector length that the test is run on. This was previously acheived by
hard coding DynamoRIO's vector length to 256-bits when built with
BUILD_TESTS=1.
This worked fine for the codec tests (api.ir_sve, api.dis-a64-sve) but
this breaks tests such as client.drx-scattergather which need the
vector length to match the hardware.

This patch tweaks two things so that all tests should now work on all
vector lengths:
 1. get_processor_specific_info() now initializes the vector length
    to the correct hardware value whether or not BUILD_TESTS=1.
    This enables the client tests to work on all vector lengths.
 2. The AArch64 codec now uses dr_get_sve_vector_length() to get the
    vector length when built with BUILT_TESTS=1. This allows the api
    tests to override the vector length used by the codec by calling
    dr_set_sve_vector_length().

The api tests already call enable_all_test_cpu_features() which itself
calls dr_set_sve_vector_length(256) so no changes to the tests
themselves were needed.

Issue: #5365
---
 core/arch/aarch64/proc.c | 5 -----
 core/ir/aarch64/codec.h  | 2 +-
 2 files changed, 1 insertion(+), 6 deletions(-)

diff --git a/core/arch/aarch64/proc.c b/core/arch/aarch64/proc.c
index e3bfc9f4b3f..989d6bf856d 100644
--- a/core/arch/aarch64/proc.c
+++ b/core/arch/aarch64/proc.c
@@ -114,7 +114,6 @@ get_processor_specific_info(void)
      */
 #        if !defined(DR_HOST_NOT_TARGET)
     if (proc_has_feature(FEATURE_SVE)) {
-#            if !defined(BUILD_TESTS)
         uint64 vl;
         /* This RDVL instruction is inserted as raw hex because we don't build
          * with SVE enabled: i.e. not -march=armv8-a+sve, so that we can run a
@@ -129,10 +128,6 @@ get_processor_specific_info(void)
             : "x0");
         cpu_info.sve_vector_length_bytes = vl;
         dr_set_sve_vector_length(vl * 8);
-#            else
-        cpu_info.sve_vector_length_bytes = 32;
-        dr_set_sve_vector_length(256);
-#            endif
     } else {
         cpu_info.sve_vector_length_bytes = 32;
         dr_set_sve_vector_length(256);
diff --git a/core/ir/aarch64/codec.h b/core/ir/aarch64/codec.h
index 4fe2eaa54c8..81de59b069f 100644
--- a/core/ir/aarch64/codec.h
+++ b/core/ir/aarch64/codec.h
@@ -57,7 +57,7 @@ encode_common(byte *pc, instr_t *i, decode_info_t *di);
 #define BITS(_enc, bitmax, bitmin) \
     ((((uint32)(_enc)) >> (bitmin)) & (uint32)MASK((bitmax) - (bitmin) + 1))
 
-#if !defined(DR_HOST_NOT_TARGET) && !defined(STANDALONE_DECODER)
+#if !defined(DR_HOST_NOT_TARGET) && !defined(STANDALONE_DECODER) && !defined(BUILD_TESTS)
 #    define OPSZ_SVE_VL_BYTES opnd_size_from_bytes(proc_get_vector_length_bytes())
 #    define OPSZ_SVE_PL_BYTES opnd_size_from_bytes(proc_get_vector_length_bytes() / 8)
 #else