[ASan] Use metadata to pass source-level information from Clang to ASan.

Instead of creating global variables for source locations and global names,
just create metadata nodes and strings. They will be transformed into actual
globals in the instrumentation pass (if necessary). This approach is more
flexible:
1) we don't have to ensure that our custom globals survive all the optimizations
2) if globals are discarded for some reason, we will simply ignore metadata for them
   and won't have to erase corresponding globals
3) metadata for source locations can be reused for other purposes: e.g. we may
   attach source location metadata to alloca instructions and provide better descriptions
   for stack variables in ASan error reports.

No functionality change.

llvm-svn: 214604

1 files changed, 8 insertions, 12 deletions

diff --git a/clang/test/CodeGen/asan-globals.cpp b/clang/test/CodeGen/asan-globals.cpp
index d9ecc646154..a9b9b5fe1fd 100644
--- a/clang/test/CodeGen/asan-globals.cpp
+++ b/clang/test/CodeGen/asan-globals.cpp
@@ -5,28 +5,24 @@
 // REQUIRES: shell
 
 int global;
-// CHECK: [[GLOBAL_LOC:@.asan_loc_descr[0-9]*]] = private unnamed_addr constant {{.*}} i32 [[@LINE-1]], i32 5
-// CHECK: [[GLOBAL_NAME:@.str[0-9]+]] = private unnamed_addr constant {{.*}} c"global\00"
 int dyn_init_global = global;
-// CHECK: [[DYN_INIT_LOC:@.asan_loc_descr[0-9]*]] = {{.*}} i32 [[@LINE-1]], i32 5
-// CHECK: [[DYN_INIT_NAME:@.str[0-9]+]] = private unnamed_addr constant {{.*}} c"dyn_init_global\00"
 int blacklisted_global;
 
 void func() {
   static int static_var = 0;
-  // CHECK: [[STATIC_LOC:@.asan_loc_descr[0-9]*]] = {{.*}} i32 [[@LINE-1]], i32 14
-  // CHECK: [[STATIC_NAME:@.str[0-9]+]] = private unnamed_addr constant {{.*}} c"static_var\00"
   const char *literal = "Hello, world!";
-  // CHECK: [[LITERAL_LOC:@.asan_loc_descr[0-9]*]] = {{.*}} i32 [[@LINE-1]], i32 25
-  // CHECK: [[LITERAL_NAME:@.str[0-9]+]] = private unnamed_addr constant {{.*}} c"<string literal>\00"
 }
 
 // CHECK: !llvm.asan.globals = !{![[GLOBAL:[0-9]+]], ![[DYN_INIT_GLOBAL:[0-9]+]], ![[BLACKLISTED_GLOBAL:[0-9]+]], ![[STATIC_VAR:[0-9]+]], ![[LITERAL:[0-9]+]]}
-// CHECK: ![[GLOBAL]] = metadata !{{{.*}} [[GLOBAL_LOC]], {{.*}} [[GLOBAL_NAME]], i1 false, i1 false}
-// CHECK: ![[DYN_INIT_GLOBAL]] = metadata !{{{.*}} [[DYN_INIT_LOC]], {{.*}} [[DYN_INIT_NAME]], i1 true, i1 false}
+// CHECK: ![[GLOBAL]] = metadata !{{{.*}} metadata ![[GLOBAL_LOC:[0-9]+]], metadata !"global", i1 false, i1 false}
+// CHECK: ![[GLOBAL_LOC]] = metadata !{metadata !"{{.*}}asan-globals.cpp", i32 7, i32 5}
+// CHECK: ![[DYN_INIT_GLOBAL]] = metadata !{{{.*}} metadata ![[DYN_INIT_LOC:[0-9]+]], metadata !"dyn_init_global", i1 true, i1 false}
+// CHECK: ![[DYN_INIT_LOC]] = metadata !{metadata !"{{.*}}asan-globals.cpp", i32 8, i32 5}
 // CHECK: ![[BLACKLISTED_GLOBAL]] = metadata !{{{.*}}, null, null, i1 false, i1 true}
-// CHECK: ![[STATIC_VAR]] = metadata !{{{.*}} [[STATIC_LOC]], {{.*}} [[STATIC_NAME]], i1 false, i1 false}
-// CHECK: ![[LITERAL]] = metadata !{{{.*}} [[LITERAL_LOC]], {{.*}} [[LITERAL_NAME]], i1 false, i1 false}
+// CHECK: ![[STATIC_VAR]] = metadata !{{{.*}} metadata ![[STATIC_LOC:[0-9]+]], metadata !"static_var", i1 false, i1 false}
+// CHECK: ![[STATIC_LOC]] = metadata !{metadata !"{{.*}}asan-globals.cpp", i32 12, i32 14}
+// CHECK: ![[LITERAL]] = metadata !{{{.*}} metadata ![[LITERAL_LOC:[0-9]+]], metadata !"<string literal>", i1 false, i1 false}
+// CHECK: ![[LITERAL_LOC]] = metadata !{metadata !"{{.*}}asan-globals.cpp", i32 13, i32 25}
 
 // BLACKLIST-SRC: !llvm.asan.globals = !{![[GLOBAL:[0-9]+]], ![[DYN_INIT_GLOBAL:[0-9]+]], ![[BLACKLISTED_GLOBAL:[0-9]+]], ![[STATIC_VAR:[0-9]+]], ![[LITERAL:[0-9]+]]}
 // BLACKLIST-SRC: ![[GLOBAL]] = metadata !{{{.*}} null, null, i1 false, i1 true}