78de7297ab
NOTE: There is a mailing list discussion on this: http://lists.llvm.org/pipermail/llvm-dev/2019-December/137632.html Complemantary to the assumption outliner prototype in D71692, this patch shows how we could simplify the code emitted for an alignemnt assumption. The generated code is smaller, less fragile, and it makes it easier to recognize the additional use as a "assumption use". As mentioned in D71692 and on the mailing list, we could adopt this scheme, and similar schemes for other patterns, without adopting the assumption outlining.
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-SANITIZE-NEXT: %[[PTRINT:.*]] = ptrtoint i8** %[[A]] to i64
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// CHECK-SANITIZE-NEXT: %[[MASKEDPTR:.*]] = and i64 %[[PTRINT]], 2147483647
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// CHECK-SANITIZE-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 true) [ "align"(i8** %[[A]], i64 2147483648) ]
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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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