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https://github.com/Gericom/teak-llvm.git
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bd1c087019
Summary: UB isn't nice. It's cool and powerful, but not nice. Having a way to detect it is nice though. [[ https://wg21.link/p1007r3 | P1007R3: std::assume_aligned ]] / http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p1007r2.pdf says: ``` We propose to add this functionality via a library function instead of a core language attribute. ... If the pointer passed in is not aligned to at least N bytes, calling assume_aligned results in undefined behaviour. ``` This differential teaches clang to sanitize all the various variants of this assume-aligned attribute. Requires D54588 for LLVM IRBuilder changes. The compiler-rt part is D54590. This is a second commit, the original one was r351105, which was mass-reverted in r351159 because 2 compiler-rt tests were failing. Reviewers: ABataev, craig.topper, vsk, rsmith, rnk, #sanitizers, erichkeane, filcab, rjmccall Reviewed By: rjmccall Subscribers: chandlerc, ldionne, EricWF, mclow.lists, cfe-commits, bkramer Tags: #sanitizers Differential Revision: https://reviews.llvm.org/D54589 llvm-svn: 351177
41 lines
3.6 KiB
C++
41 lines
3.6 KiB
C++
// RUN: %clang_cc1 -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s --check-prefixes=CHECK,CHECK-NOSANITIZE
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// RUN: %clang_cc1 -fsanitize=alignment -fno-sanitize-recover=alignment -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s -implicit-check-not="call void @__ubsan_handle_alignment_assumption" --check-prefixes=CHECK,CHECK-SANITIZE,CHECK-SANITIZE-ANYRECOVER,CHECK-SANITIZE-NORECOVER,CHECK-SANITIZE-UNREACHABLE
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// RUN: %clang_cc1 -fsanitize=alignment -fsanitize-recover=alignment -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s -implicit-check-not="call void @__ubsan_handle_alignment_assumption" --check-prefixes=CHECK,CHECK-SANITIZE,CHECK-SANITIZE-ANYRECOVER,CHECK-SANITIZE-RECOVER
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// RUN: %clang_cc1 -fsanitize=alignment -fsanitize-trap=alignment -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s -implicit-check-not="call void @__ubsan_handle_alignment_assumption" --check-prefixes=CHECK,CHECK-SANITIZE,CHECK-SANITIZE-TRAP,CHECK-SANITIZE-UNREACHABLE
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typedef char **__attribute__((align_value(0x80000000))) aligned_char;
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struct ac_struct {
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// CHECK: %[[STRUCT_AC_STRUCT:.*]] = type { i8** }
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aligned_char a;
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};
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// CHECK-SANITIZE-ANYRECOVER: @[[ALIGNED_CHAR:.*]] = {{.*}} c"'aligned_char' (aka 'char **')\00" }
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// CHECK-SANITIZE-ANYRECOVER: @[[LINE_100_ALIGNMENT_ASSUMPTION:.*]] = {{.*}}, i32 100, i32 13 }, {{.*}}* @[[ALIGNED_CHAR]] }
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char **load_from_ac_struct(struct ac_struct *x) {
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// CHECK: define i8** @{{.*}}(%[[STRUCT_AC_STRUCT]]* %[[X:.*]])
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// CHECK-NEXT: [[ENTRY:.*]]:
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// CHECK-NEXT: %[[STRUCT_AC_STRUCT_ADDR:.*]] = alloca %[[STRUCT_AC_STRUCT]]*, align 8
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// CHECK-NEXT: store %[[STRUCT_AC_STRUCT]]* %[[X]], %[[STRUCT_AC_STRUCT]]** %[[STRUCT_AC_STRUCT_ADDR]], align 8
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// CHECK-NEXT: %[[X_RELOADED:.*]] = load %[[STRUCT_AC_STRUCT]]*, %[[STRUCT_AC_STRUCT]]** %[[STRUCT_AC_STRUCT_ADDR]], align 8
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// CHECK: %[[A_ADDR:.*]] = getelementptr inbounds %[[STRUCT_AC_STRUCT]], %[[STRUCT_AC_STRUCT]]* %[[X_RELOADED]], i32 0, i32 0
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// CHECK: %[[A:.*]] = load i8**, i8*** %[[A_ADDR]], align 8
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// CHECK-NEXT: %[[PTRINT:.*]] = ptrtoint i8** %[[A]] to i64
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// CHECK-NEXT: %[[MASKEDPTR:.*]] = and i64 %[[PTRINT]], 2147483647
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// CHECK-NEXT: %[[MASKCOND:.*]] = icmp eq i64 %[[MASKEDPTR]], 0
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// CHECK-SANITIZE-NEXT: %[[PTRINT_DUP:.*]] = ptrtoint i8** %[[A]] to i64, !nosanitize
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// CHECK-SANITIZE-NEXT: br i1 %[[MASKCOND]], label %[[CONT:.*]], label %[[HANDLER_ALIGNMENT_ASSUMPTION:[^,]+]],{{.*}} !nosanitize
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// CHECK-SANITIZE: [[HANDLER_ALIGNMENT_ASSUMPTION]]:
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// CHECK-SANITIZE-NORECOVER-NEXT: call void @__ubsan_handle_alignment_assumption_abort(i8* bitcast ({ {{{.*}}}, {{{.*}}}, {{{.*}}}* }* @[[LINE_100_ALIGNMENT_ASSUMPTION]] to i8*), i64 %[[PTRINT_DUP]], i64 2147483648, i64 0){{.*}}, !nosanitize
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// CHECK-SANITIZE-RECOVER-NEXT: call void @__ubsan_handle_alignment_assumption(i8* bitcast ({ {{{.*}}}, {{{.*}}}, {{{.*}}}* }* @[[LINE_100_ALIGNMENT_ASSUMPTION]] to i8*), i64 %[[PTRINT_DUP]], i64 2147483648, i64 0){{.*}}, !nosanitize
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// CHECK-SANITIZE-TRAP-NEXT: call void @llvm.trap(){{.*}}, !nosanitize
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// CHECK-SANITIZE-UNREACHABLE-NEXT: unreachable, !nosanitize
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// CHECK-SANITIZE: [[CONT]]:
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// CHECK-NEXT: call void @llvm.assume(i1 %[[MASKCOND]])
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// CHECK-NEXT: ret i8** %[[A]]
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// CHECK-NEXT: }
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#line 100
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return x->a;
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}
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