jgalenson created this revision.
jgalenson added reviewers: eugenis, chandlerc.
Herald added a subscriber: cfe-commits.
Running the bounds checking sanitizer earlier makes it easier for other
optimizations to remove the checks it inserts.
While it could also inhibit other optimizations, I ran a few benchmarks and
this did seem to improve performance and code size slightly.
Note that I'm not sure how to hook this up to the new PM, as I couldn't find a
similar hook into the beginning of the pipeline. Are there any suggestions on
what to do about that, or is it fine for this to work just on the old PM?
Repository:
rC Clang
https://reviews.llvm.org/D49492
Files:
lib/CodeGen/BackendUtil.cpp
test/CodeGen/bounds-checking-opt.c
Index: test/CodeGen/bounds-checking-opt.c
===================================================================
--- /dev/null
+++ test/CodeGen/bounds-checking-opt.c
@@ -0,0 +1,20 @@
+// RUN: %clang -S -fsanitize=local-bounds -emit-llvm -target x86_64-- %s -o -
| FileCheck -check-prefix=O0 %s
+// RUN: %clang -S -fsanitize=local-bounds -emit-llvm -target x86_64-- -O2 %s
-o - | FileCheck -check-prefix=O2 %s
+// RUN: %clang -S -fsanitize=local-bounds -emit-llvm -target aarch64-- %s -o -
| FileCheck -check-prefix=O0 %s
+// RUN: %clang -S -fsanitize=local-bounds -emit-llvm -target aarch64-- -O2 %s
-o - | FileCheck -check-prefix=O2 %s
+
+extern void fill(int *arr);
+
+// CHECK-LABEL: @f
+int f(int x) {
+ // O0: call {{.*}} @llvm.trap
+ // O2-NOT: call {{.*}} @llvm.trap
+ int foo[1000];
+ fill(foo);
+ int sum = 0;
+ #pragma clang loop vectorize(disable)
+ #pragma clang loop unroll(disable)
+ for (unsigned i = 0; i < 1000; i++)
+ sum += foo[i];
+ return sum;
+}
Index: lib/CodeGen/BackendUtil.cpp
===================================================================
--- lib/CodeGen/BackendUtil.cpp
+++ lib/CodeGen/BackendUtil.cpp
@@ -562,7 +562,7 @@
addCoroutinePassesToExtensionPoints(PMBuilder);
if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds)) {
- PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
+ PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
addBoundsCheckingPass);
PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
addBoundsCheckingPass);
Index: test/CodeGen/bounds-checking-opt.c
===================================================================
--- /dev/null
+++ test/CodeGen/bounds-checking-opt.c
@@ -0,0 +1,20 @@
+// RUN: %clang -S -fsanitize=local-bounds -emit-llvm -target x86_64-- %s -o - | FileCheck -check-prefix=O0 %s
+// RUN: %clang -S -fsanitize=local-bounds -emit-llvm -target x86_64-- -O2 %s -o - | FileCheck -check-prefix=O2 %s
+// RUN: %clang -S -fsanitize=local-bounds -emit-llvm -target aarch64-- %s -o - | FileCheck -check-prefix=O0 %s
+// RUN: %clang -S -fsanitize=local-bounds -emit-llvm -target aarch64-- -O2 %s -o - | FileCheck -check-prefix=O2 %s
+
+extern void fill(int *arr);
+
+// CHECK-LABEL: @f
+int f(int x) {
+ // O0: call {{.*}} @llvm.trap
+ // O2-NOT: call {{.*}} @llvm.trap
+ int foo[1000];
+ fill(foo);
+ int sum = 0;
+ #pragma clang loop vectorize(disable)
+ #pragma clang loop unroll(disable)
+ for (unsigned i = 0; i < 1000; i++)
+ sum += foo[i];
+ return sum;
+}
Index: lib/CodeGen/BackendUtil.cpp
===================================================================
--- lib/CodeGen/BackendUtil.cpp
+++ lib/CodeGen/BackendUtil.cpp
@@ -562,7 +562,7 @@
addCoroutinePassesToExtensionPoints(PMBuilder);
if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds)) {
- PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
+ PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
addBoundsCheckingPass);
PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
addBoundsCheckingPass);
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