Subzero: Elide checks of known valid accesses of locals

tests_lit/asan_tests/elidelocalchecks.ll

Index: tests_lit/asan_tests/elidelocalchecks.ll
diff --git a/tests_lit/asan_tests/elidelocalchecks.ll b/tests_lit/asan_tests/elidelocalchecks.ll
new file mode 100644
index 0000000000000000000000000000000000000000..2a0b16db0cfe988fdd9e9238f56480e2735b74f2
--- /dev/null
+++ b/tests_lit/asan_tests/elidelocalchecks.ll
@@ -0,0 +1,105 @@
+; Test that direct loads and stores of local variables are not checked.
+
+; REQUIRES: allow_dump
+
+; RUN: %p2i -i %s --args -verbose=inst -threads=0 -fsanitize-address \
+; RUN:     | FileCheck --check-prefix=DUMP %s
+
+define internal void @foo() {
+  %ptr8 = alloca i8, i32 1, align 4
+  %ptr16 = alloca i8, i32 2, align 4
+  %ptr32 = alloca i8, i32 4, align 4
+  %ptr64 = alloca i8, i32 8, align 4
+  %ptr128 = alloca i8, i32 16, align 4
+
+  %target8 = bitcast i8* %ptr8 to i8*
+  %target16 = bitcast i8* %ptr16 to i16*
+  %target32 = bitcast i8* %ptr32 to i32*
+  %target64 = bitcast i8* %ptr64 to i64*
+  %target128 = bitcast i8* %ptr128 to <4 x i32>*
+
+  ; unchecked loads
+  %loaded8 = load i8, i8* %target8, align 1
+  %loaded16 = load i16, i16* %target16, align 1
+  %loaded32 = load i32, i32* %target32, align 1
+  %loaded64 = load i64, i64* %target64, align 1
+  %loaded128 = load <4 x i32>, <4 x i32>* %target128, align 4
+
+  ; unchecked stores
+  store i8 %loaded8, i8* %target8, align 1
+  store i16 %loaded16, i16* %target16, align 1
+  store i32 %loaded32, i32* %target32, align 1
+  store i64 %loaded64, i64* %target64, align 1
+  store <4 x i32> %loaded128, <4 x i32>* %target128, align 4
+
+  %addr8 = ptrtoint i8* %ptr8 to i32
+  %addr16 = ptrtoint i8* %ptr16 to i32
+  %addr32 = ptrtoint i8* %ptr32 to i32
+  %addr64 = ptrtoint i8* %ptr64 to i32
+  %addr128 = ptrtoint i8* %ptr128 to i32
+
+  %off8 = add i32 %addr8, -1
+  %off16 = add i32 %addr16, -1
+  %off32 = add i32 %addr32, -1
+  %off64 = add i32 %addr64, -1
+  %off128 = add i32 %addr128, -1
+
+  %offtarget8 = inttoptr i32 %off8 to i8*
+  %offtarget16 = inttoptr i32 %off16 to i16*
+  %offtarget32 = inttoptr i32 %off32 to i32*
+  %offtarget64 = inttoptr i32 %off64 to i64*
+  %offtarget128 = inttoptr i32 %off128 to <4 x i32>*
+
+  ; checked loads
+  %offloaded8 = load i8, i8* %offtarget8, align 1
+  %offloaded16 = load i16, i16* %offtarget16, align 1
+  %offloaded32 = load i32, i32* %offtarget32, align 1
+  %offloaded64 = load i64, i64* %offtarget64, align 1
+  %offloaded128 = load <4 x i32>, <4 x i32>* %offtarget128, align 4
+
+  ; checked stores
+  store i8 %offloaded8, i8* %offtarget8, align 1
+  store i16 %offloaded16, i16* %offtarget16, align 1
+  store i32 %offloaded32, i32* %offtarget32, align 1
+  store i64 %offloaded64, i64* %offtarget64, align 1
+  store <4 x i32> %offloaded128, <4 x i32>* %offtarget128, align 4
+
+  ret void
+}
+
+; DUMP-LABEL: ================ Instrumented CFG ================
+; DUMP-NEXT: define internal void @foo() {
+
+; Unchecked loads and stores
+; DUMP: %loaded8 = load i8, i8* %ptr8, align 1
+; DUMP-NEXT: %loaded16 = load i16, i16* %ptr16, align 1
+; DUMP-NEXT: %loaded32 = load i32, i32* %ptr32, align 1
+; DUMP-NEXT: %loaded64 = load i64, i64* %ptr64, align 1
+; DUMP-NEXT: %loaded128 = load <4 x i32>, <4 x i32>* %ptr128, align 4
+; DUMP-NEXT: store i8 %loaded8, i8* %ptr8, align 1
+; DUMP-NEXT: store i16 %loaded16, i16* %ptr16, align 1
+; DUMP-NEXT: store i32 %loaded32, i32* %ptr32, align 1
+; DUMP-NEXT: store i64 %loaded64, i64* %ptr64, align 1
+; DUMP-NEXT: store <4 x i32> %loaded128, <4 x i32>* %ptr128, align 4
+
+; Checked loads and stores
+; DUMP: call void @__asan_check_load(i32 %off8, i32 1)
+; DUMP-NEXT: %offloaded8 = load i8, i8* %off8, align 1
+; DUMP-NEXT: call void @__asan_check_load(i32 %off16, i32 2)
+; DUMP-NEXT: %offloaded16 = load i16, i16* %off16, align 1
+; DUMP-NEXT: call void @__asan_check_load(i32 %off32, i32 4)
+; DUMP-NEXT: %offloaded32 = load i32, i32* %off32, align 1
+; DUMP-NEXT: call void @__asan_check_load(i32 %off64, i32 8)
+; DUMP-NEXT: %offloaded64 = load i64, i64* %off64, align 1
+; DUMP-NEXT: call void @__asan_check_load(i32 %off128, i32 16)
+; DUMP-NEXT: %offloaded128 = load <4 x i32>, <4 x i32>* %off128, align 4
+; DUMP-NEXT: call void @__asan_check_store(i32 %off8, i32 1)
+; DUMP-NEXT: store i8 %offloaded8, i8* %off8, align 1
+; DUMP-NEXT: call void @__asan_check_store(i32 %off16, i32 2)
+; DUMP-NEXT: store i16 %offloaded16, i16* %off16, align 1
+; DUMP-NEXT: call void @__asan_check_store(i32 %off32, i32 4)
+; DUMP-NEXT: store i32 %offloaded32, i32* %off32, align 1
+; DUMP-NEXT: call void @__asan_check_store(i32 %off64, i32 8)
+; DUMP-NEXT: store i64 %offloaded64, i64* %off64, align 1
+; DUMP-NEXT: call void @__asan_check_store(i32 %off128, i32 16)
+; DUMP-NEXT: store <4 x i32> %offloaded128, <4 x i32>* %off128, align 4