From: George Burgess IV <george.burgess.iv@gmail.com>
Date: Wed, 17 Jan 2018 04:46:04 +0000 (+0000)
Subject: [CodeGen] Fix a crash on mangling multiversioned functions
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=8497b287c57ae218ac0ac7c326d89cbd108b3860;p=clang

[CodeGen] Fix a crash on mangling multiversioned functions

`multiVersionSortPriority` expects features to have no prefix. We
currently carry them around in the format "+${feature}".


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@322618 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index fb16c8f260..68c8287084 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -753,8 +753,12 @@ static void AppendTargetMangling(const CodeGenModule &CGM,
   const auto &Target = CGM.getTarget();
   TargetAttr::ParsedTargetAttr Info =
       Attr->parse([&Target](StringRef LHS, StringRef RHS) {
-                    return Target.multiVersionSortPriority(LHS) >
-                           Target.multiVersionSortPriority(RHS);
+                    // Multiversioning doesn't allow "no-${feature}", so we can
+                    // only have "+" prefixes here.
+                    assert(LHS.startswith("+") && RHS.startswith("+") &&
+                           "Features should always have a prefix.");
+                    return Target.multiVersionSortPriority(LHS.substr(1)) >
+                           Target.multiVersionSortPriority(RHS.substr(1));
                   });
 
   bool IsFirst = true;
diff --git a/test/CodeGen/attr-target-mv.c b/test/CodeGen/attr-target-mv.c
index ca3d7d2971..0085a154ce 100644
--- a/test/CodeGen/attr-target-mv.c
+++ b/test/CodeGen/attr-target-mv.c
@@ -25,6 +25,14 @@ void bar3() {
 inline __attribute__((target("default"))) void foo_decls(void) {}
 inline __attribute__((target("sse4.2"))) void foo_decls(void) {}
 
+inline __attribute__((target("default"))) void foo_multi(void) {}
+inline __attribute__((target("avx,sse4.2"))) void foo_multi(void) {}
+inline __attribute__((target("sse4.2,fma4"))) void foo_multi(void) {}
+inline __attribute__((target("arch=ivybridge,fma4,sse4.2"))) void foo_multi(void) {}
+void bar4() {
+  foo_multi();
+}
+
 // CHECK: @foo.ifunc = ifunc i32 (), i32 ()* ()* @foo.resolver
 // CHECK: @foo_inline.ifunc = ifunc i32 (), i32 ()* ()* @foo_inline.resolver
 // CHECK: @foo_decls.ifunc = ifunc void (), void ()* ()* @foo_decls.resolver
@@ -77,3 +85,7 @@ inline __attribute__((target("sse4.2"))) void foo_decls(void) {}
 // CHECK: define available_externally void @foo_decls()
 // CHECK: define available_externally void @foo_decls.sse4.2()
 
+// CHECK: define available_externally void @foo_multi.avx_sse4.2()
+// CHECK: define available_externally void @foo_multi.fma4_sse4.2()
+// CHECK: define available_externally void @foo_multi.arch_ivybridge_fma4_sse4.2()
+