From: Nicolai Hähnle <nicolai.haeh...@amd.com>
They can lead to VM faults and worse, which goes against the GL robustness
promises.
---
src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c
b/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c
index 7cdf228..88c7b3c 100644
--- a/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c
+++ b/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c
@@ -232,20 +232,35 @@ get_pointer_into_array(struct radeon_llvm_context *ctx,
if (!alloca)
return NULL;
array = &ctx->temp_arrays[array_id - 1];
if (!(array->writemask & (1 << swizzle)))
return ctx->undef_alloca;
index = emit_array_index(&ctx->soa, reg_indirect,
reg_index - ctx->temp_arrays[array_id -
1].range.First);
+
+ /* Ensure that the index is within a valid range, to guard against
+ * VM faults and overwriting critical data (e.g. spilled resource
+ * descriptors).
+ *
+ * TODO It should be possible to avoid the additional instructions
+ * if LLVM is changed so that it guarantuees:
+ * 1. the scratch space descriptor isolates the current wave (this
+ * could even save the scratch offset SGPR at the cost of an
+ * additional SALU instruction)
+ * 2. the memory for allocas must be allocated at the _end_ of the
+ * scratch space (after spilled registers)
+ */
+ index = radeon_llvm_bound_index(ctx, index, array->range.Last -
array->range.First + 1);
+
index = LLVMBuildMul(
builder, index,
lp_build_const_int32(gallivm, util_bitcount(array->writemask)),
"");
index = LLVMBuildAdd(
builder, index,
lp_build_const_int32(
gallivm,
util_bitcount(array->writemask & ((1 << swizzle) - 1))),
"");
--
2.7.4
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