mesa/patches/mesa-10.2.7-gallivm-set-mcpu-when-initializing-llvm-execution-en.patch

From ebe30fd4d4a90219431b6947f233473b2cf518a5 Mon Sep 17 00:00:00 2001
From: Roland Scheidegger <sroland@vmware.com>
Date: Thu, 19 Jun 2014 03:27:26 +0200
Subject: [PATCH 2/2] gallivm: set mcpu when initializing llvm execution engine

Previously llvm detected cpu features automatically when the execution engine
was created (based on host cpu). This is no longer the case, which meant llvm
was then not able to emit some of the intrinsics we used as we didn't specify
any sse attributes (only on avx supporting systems this was not a problem since
despite at least some llvm versions enabling it anyway we always set this
manually). So, instead of trying to figure out which MAttrs to set just set
MCPU.

This fixes https://bugs.freedesktop.org/show_bug.cgi?id=77493.

Reviewed-by: Jose Fonseca <jfonseca@vmware.com>
Tested-by: Vinson Lee <vlee@freedesktop.org>
(cherry picked from commit cad60420d5ea36a4b6fa2e6c91317f71423aa63e)
---
 src/gallium/auxiliary/gallivm/lp_bld_misc.cpp | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp b/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp
index 45c985d..395ac7b 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp
+++ b/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp
@@ -59,6 +59,7 @@
 #include <llvm/ExecutionEngine/JITMemoryManager.h>
 #endif
 #include <llvm/Support/CommandLine.h>
+#include <llvm/Support/Host.h>
 #include <llvm/Support/PrettyStackTrace.h>
 
 #if HAVE_LLVM >= 0x0300
@@ -309,8 +310,8 @@ lp_build_create_jit_compiler_for_module(LLVMExecutionEngineRef *OutJIT,
       /*
        * AVX feature is not automatically detected from CPUID by the X86 target
        * yet, because the old (yet default) JIT engine is not capable of
-       * emitting the opcodes.  But as we're using MCJIT here, it is safe to
-       * add set this attribute.
+       * emitting the opcodes. On newer llvm versions it is and at least some
+       * versions (tested with 3.3) will emit avx opcodes without this anyway.
        */
       MAttrs.push_back("+avx");
       if (util_cpu_caps.has_f16c) {
@@ -318,9 +319,28 @@ lp_build_create_jit_compiler_for_module(LLVMExecutionEngineRef *OutJIT,
       }
       builder.setMAttrs(MAttrs);
    }
+
+#if HAVE_LLVM >= 0x0305
+   StringRef MCPU = llvm::sys::getHostCPUName();
+   /*
+    * The cpu bits are no longer set automatically, so need to set mcpu manually.
+    * Note that the MAttrs set above will be sort of ignored (since we should
+    * not set any which would not be set by specifying the cpu anyway).
+    * It ought to be safe though since getHostCPUName() should include bits
+    * not only from the cpu but environment as well (for instance if it's safe
+    * to use avx instructions which need OS support). According to
+    * http://llvm.org/bugs/show_bug.cgi?id=19429 however if I understand this
+    * right it may be necessary to specify older cpu (or disable mattrs) though
+    * when not using MCJIT so no instructions are generated which the old JIT
+    * can't handle. Not entirely sure if we really need to do anything yet.
+    */
+   builder.setMCPU(MCPU);
+#endif
+
    builder.setJITMemoryManager(JITMemoryManager::CreateDefaultMemManager());
 
    ExecutionEngine *JIT;
+
 #if HAVE_LLVM >= 0x0302
    JIT = builder.create();
 #else
-- 
2.1.0

1	From ebe30fd4d4a90219431b6947f233473b2cf518a5 Mon Sep 17 00:00:00 2001
2	From: Roland Scheidegger <sroland@vmware.com>
3	Date: Thu, 19 Jun 2014 03:27:26 +0200
4	Subject: [PATCH 2/2] gallivm: set mcpu when initializing llvm execution engine
5
6	Previously llvm detected cpu features automatically when the execution engine
7	was created (based on host cpu). This is no longer the case, which meant llvm
8	was then not able to emit some of the intrinsics we used as we didn't specify
9	any sse attributes (only on avx supporting systems this was not a problem since
10	despite at least some llvm versions enabling it anyway we always set this
11	manually). So, instead of trying to figure out which MAttrs to set just set
12	MCPU.
13
14	This fixes https://bugs.freedesktop.org/show_bug.cgi?id=77493.
15
16	Reviewed-by: Jose Fonseca <jfonseca@vmware.com>
17	Tested-by: Vinson Lee <vlee@freedesktop.org>
18	(cherry picked from commit cad60420d5ea36a4b6fa2e6c91317f71423aa63e)
19	---
20	src/gallium/auxiliary/gallivm/lp_bld_misc.cpp \| 24 ++++++++++++++++++++++--
21	1 file changed, 22 insertions(+), 2 deletions(-)
22
23	diff --git a/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp b/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp
24	index 45c985d..395ac7b 100644
25	--- a/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp
26	+++ b/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp
27	@@ -59,6 +59,7 @@
28	#include <llvm/ExecutionEngine/JITMemoryManager.h>
29	#endif
30	#include <llvm/Support/CommandLine.h>
31	+#include <llvm/Support/Host.h>
32	#include <llvm/Support/PrettyStackTrace.h>
33
34	#if HAVE_LLVM >= 0x0300
35	@@ -309,8 +310,8 @@ lp_build_create_jit_compiler_for_module(LLVMExecutionEngineRef *OutJIT,
36	/*
37	* AVX feature is not automatically detected from CPUID by the X86 target
38	* yet, because the old (yet default) JIT engine is not capable of
39	- * emitting the opcodes. But as we're using MCJIT here, it is safe to
40	- * add set this attribute.
41	+ * emitting the opcodes. On newer llvm versions it is and at least some
42	+ * versions (tested with 3.3) will emit avx opcodes without this anyway.
43	*/
44	MAttrs.push_back("+avx");
45	if (util_cpu_caps.has_f16c) {
46	@@ -318,9 +319,28 @@ lp_build_create_jit_compiler_for_module(LLVMExecutionEngineRef *OutJIT,
47	}
48	builder.setMAttrs(MAttrs);
49	}
50	+
51	+#if HAVE_LLVM >= 0x0305
52	+ StringRef MCPU = llvm::sys::getHostCPUName();
53	+ /*
54	+ * The cpu bits are no longer set automatically, so need to set mcpu manually.
55	+ * Note that the MAttrs set above will be sort of ignored (since we should
56	+ * not set any which would not be set by specifying the cpu anyway).
57	+ * It ought to be safe though since getHostCPUName() should include bits
58	+ * not only from the cpu but environment as well (for instance if it's safe
59	+ * to use avx instructions which need OS support). According to
60	+ * http://llvm.org/bugs/show_bug.cgi?id=19429 however if I understand this
61	+ * right it may be necessary to specify older cpu (or disable mattrs) though
62	+ * when not using MCJIT so no instructions are generated which the old JIT
63	+ * can't handle. Not entirely sure if we really need to do anything yet.
64	+ */
65	+ builder.setMCPU(MCPU);
66	+#endif
67	+
68	builder.setJITMemoryManager(JITMemoryManager::CreateDefaultMemManager());
69
70	ExecutionEngine *JIT;
71	+
72	#if HAVE_LLVM >= 0x0302
73	JIT = builder.create();
74	#else
75	--
76	2.1.0
77