c34d343f15
This patch makes ubsan's nonnull return value diagnostics more precise,
which makes the diagnostics more useful when there are multiple return
statements in a function. Example:
1 |__attribute__((returns_nonnull)) char *foo() {
2 | if (...) {
3 | return expr_which_might_evaluate_to_null();
4 | } else {
5 | return another_expr_which_might_evaluate_to_null();
6 | }
7 |} // <- The current diagnostic always points here!
runtime error: Null returned from Line 7, Column 2!
With this patch, the diagnostic would point to either Line 3, Column 5
or Line 5, Column 5.
This is done by emitting source location metadata for each return
statement in a sanitized function. The runtime is passed a pointer to
the appropriate metadata so that it can prepare and deduplicate reports.
Compiler-rt patch (with more tests): https://reviews.llvm.org/D34298
Differential Revision: https://reviews.llvm.org/D34299
llvm-svn: 306163
62 lines
2.3 KiB
Objective-C
62 lines
2.3 KiB
Objective-C
// REQUIRES: asserts
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// RUN: %clang_cc1 -x objective-c -emit-llvm -triple x86_64-apple-macosx10.10.0 -fsanitize=nullability-return,returns-nonnull-attribute,nullability-arg,nonnull-attribute %s -o - -w | FileCheck %s
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// If both the annotation and the attribute are present, prefer the attribute,
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// since it actually affects IRGen.
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// CHECK-LABEL: define nonnull i32* @f1
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__attribute__((returns_nonnull)) int *_Nonnull f1(int *_Nonnull p) {
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// CHECK: entry:
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// CHECK-NEXT: [[SLOC_PTR:%.*]] = alloca i8*
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// CHECK-NEXT: [[ADDR:%.*]] = alloca i32*
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// CHECK-NEXT: store i8* null, i8** [[SLOC_PTR]]
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// CHECK-NEXT: store i32* [[P:%.*]], i32** [[ADDR]]
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// CHECK-NEXT: store {{.*}} [[SLOC_PTR]]
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// CHECK-NEXT: [[ARG:%.*]] = load i32*, i32** [[ADDR]]
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// CHECK-NEXT: [[SLOC:%.*]] = load {{.*}} [[SLOC_PTR]]
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// CHECK-NEXT: [[SLOC_NONNULL:%.*]] = icmp ne i8* [[SLOC]], null
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// CHECK-NEXT: br i1 [[SLOC_NONNULL]], label %nullcheck
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//
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// CHECK: nullcheck:
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// CHECK-NEXT: [[ICMP:%.*]] = icmp ne i32* [[ARG]], null, !nosanitize
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// CHECK-NEXT: br i1 [[ICMP]], label %[[CONT:.+]], label %[[HANDLE:[^,]+]]
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// CHECK: [[HANDLE]]:
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// CHECK: call void @__ubsan_handle_nonnull_return
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// CHECK-NEXT: unreachable, !nosanitize
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// CHECK: [[CONT]]:
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// CHECK-NEXT: br label %no.nullcheck
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// CHECK: no.nullcheck:
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// CHECK-NEXT: ret i32* [[ARG]]
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return p;
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}
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// CHECK-LABEL: define void @f2
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void f2(int *_Nonnull __attribute__((nonnull)) p) {}
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// CHECK-LABEL: define void @call_f2
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void call_f2() {
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// CHECK: call void @__ubsan_handle_nonnull_arg_abort
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// CHECK-NOT: call void @__ubsan_handle_nonnull_arg_abort
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f2((void *)0);
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}
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// If the return value isn't meant to be checked, make sure we don't check it.
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// CHECK-LABEL: define i32* @f3
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int *f3(int *p) {
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// CHECK-NOT: return.sloc
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// CHECK-NOT: call{{.*}}ubsan
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return p;
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}
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// Check for a valid "return" source location, even when there is no return
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// statement, to avoid accidentally calling the runtime.
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// CHECK-LABEL: define nonnull i32* @f4
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__attribute__((returns_nonnull)) int *f4() {
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// CHECK: store i8* null, i8** [[SLOC_PTR:%.*]]
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// CHECK: [[SLOC:%.*]] = load {{.*}} [[SLOC_PTR]]
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// CHECK: [[SLOC_NONNULL:%.*]] = icmp ne i8* [[SLOC]], null
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// CHECK: br i1 [[SLOC_NONNULL]], label %nullcheck
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// CHECK: nullcheck:
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}
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