Subzero: Implemented codegen for poisoning and unpoisoning stack redzones

tests_lit/asan_tests/blacklist.ll

 ; Test to ensure that blacklisted functions are not instrumented and others are.
 
 ; REQUIRES: allow_dump
 
 ; RUN: %p2i -i %s --args -verbose=inst -threads=0 -fsanitize-address \
 ; RUN:     -allow-externally-defined-symbols | FileCheck --check-prefix=DUMP %s
 
 declare external i32 @malloc(i32)
 declare external void @free(i32)
 
@@ skipping 18 matching lines @@
 define internal void @func() {
   %local = alloca i8, i32 4, align 4
   %heapvar = call i32 @malloc(i32 42)
   call void @free(i32 %heapvar)
   ret void
 }
 
 ; DUMP-LABEL: ================ Instrumented CFG ================
 ; DUMP-NEXT: define internal void @func() {
 ; DUMP-NEXT: __0:
+; DUMP-NEXT:   %__$rz0 = alloca i8, i32 32, align 8
 ; DUMP-NEXT:   %local = alloca i8, i32 64, align 8
-; DUMP-NEXT:   %__$rz1 = alloca i8, i32 32, align 8
-; DUMP-NEXT:   call void @__asan_poison(i32 %__$rz1, i32 32, i32 -1)
-; DUMP-NEXT:   %__$rz0 = add i32 %local, 4
-; DUMP-NEXT:   call void @__asan_poison(i32 %__$rz0, i32 60, i32 -1)
+; DUMP-NEXT:   %shadowIndex = lshr i32 %__$rz0, 3
+; DUMP-NEXT:   %firstShadowLoc = add i32 %shadowIndex, 536870912
+; DUMP-NEXT:   %__5 = add i32 %firstShadowLoc, 0
+; DUMP-NEXT:   store i32 -1, i32* %__5, align 1
+; DUMP-NEXT:   %__6 = add i32 %firstShadowLoc, 4
+; DUMP-NEXT:   store i32 -252, i32* %__6, align 1
+; DUMP-NEXT:   %__7 = add i32 %firstShadowLoc, 8
+; DUMP-NEXT:   store i32 -1, i32* %__7, align 1
 ; DUMP-NEXT:   %heapvar = call i32 @__asan_malloc(i32 42)
 ; DUMP-NEXT:   call void @__asan_free(i32 %heapvar)
-; DUMP-NEXT:   call void @__asan_unpoison(i32 %__$rz0, i32 60)
-; DUMP-NEXT:   call void @__asan_unpoison(i32 %__$rz1, i32 32)
+; DUMP-NEXT:   store i32 0, i32* %__5, align 1
+; DUMP-NEXT:   store i32 0, i32* %__6, align 1
+; DUMP-NEXT:   store i32 0, i32* %__7, align 1
 ; DUMP-NEXT:   ret void
 ; DUMP-NEXT: }