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https://github.com/capstone-engine/llvm-capstone.git
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7892c37455
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. 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: 351105
53 lines
4.5 KiB
C++
53 lines
4.5 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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// CHECK-SANITIZE-ANYRECOVER: @[[CHAR:.*]] = {{.*}} c"'char **'\00" }
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// CHECK-SANITIZE-ANYRECOVER: @[[LINE_100_ALIGNMENT_ASSUMPTION:.*]] = {{.*}}, i32 100, i32 10 }, {{.*}}* @[[CHAR]] }
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char **__attribute__((alloc_align(2)))
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passthrough(char **x, unsigned long alignment) {
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// CHECK: define i8** @[[PASSTHROUGH:.*]](i8** %[[X:.*]], i64 %[[ALIGNMENT:.*]])
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// CHECK-NEXT: entry:
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// CHECK-NEXT: %[[X_ADDR:.*]] = alloca i8**, align 8
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// CHECK-NEXT: %[[ALIGNMENT_ADDR:.*]] = alloca i64, align 8
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// CHECK-NEXT: store i8** %[[X]], i8*** %[[X_ADDR]], align 8
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// CHECK-NEXT: store i64 %[[ALIGNMENT]], i64* %[[ALIGNMENT_ADDR]], align 8
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// CHECK-NEXT: %[[X_RELOADED:.*]] = load i8**, i8*** %[[X_ADDR]], align 8
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// CHECK-NEXT: ret i8** %[[X_RELOADED]]
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// CHECK-NEXT: }
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return x;
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}
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char **caller(char **x, unsigned long alignment) {
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// CHECK: define i8** @{{.*}}(i8** %[[X:.*]], i64 %[[ALIGNMENT:.*]])
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// CHECK-NEXT: entry:
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// CHECK-NEXT: %[[X_ADDR:.*]] = alloca i8**, align 8
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// CHECK-NEXT: %[[ALIGNMENT_ADDR:.*]] = alloca i64, align 8
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// CHECK-NEXT: store i8** %[[X]], i8*** %[[X_ADDR]], align 8
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// CHECK-NEXT: store i64 %[[ALIGNMENT]], i64* %[[ALIGNMENT_ADDR]], align 8
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// CHECK-NEXT: %[[X_RELOADED:.*]] = load i8**, i8*** %[[X_ADDR]], align 8
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// CHECK-NEXT: %[[ALIGNMENT_RELOADED:.*]] = load i64, i64* %[[ALIGNMENT_ADDR]], align 8
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// CHECK-NEXT: %[[X_RETURNED:.*]] = call i8** @[[PASSTHROUGH]](i8** %[[X_RELOADED]], i64 %[[ALIGNMENT_RELOADED]])
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// CHECK-NEXT: %[[ISPOSITIVE:.*]] = icmp sgt i64 %[[ALIGNMENT_RELOADED]], 0
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// CHECK-NEXT: %[[POSITIVEMASK:.*]] = sub i64 %[[ALIGNMENT_RELOADED]], 1
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// CHECK-NEXT: %[[MASK:.*]] = select i1 %[[ISPOSITIVE]], i64 %[[POSITIVEMASK]], i64 0
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// CHECK-NEXT: %[[PTRINT:.*]] = ptrtoint i8** %[[X_RETURNED]] to i64
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// CHECK-NEXT: %[[MASKEDPTR:.*]] = and i64 %[[PTRINT]], %[[MASK]]
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// CHECK-NEXT: %[[MASKCOND:.*]] = icmp eq i64 %[[MASKEDPTR]], 0
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// CHECK-SANITIZE-NEXT: %[[PTRINT_DUP:.*]] = ptrtoint i8** %[[X_RETURNED]] 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 %[[ALIGNMENT_RELOADED]], 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 %[[ALIGNMENT_RELOADED]], 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** %[[X_RETURNED]]
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// CHECK-NEXT: }
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#line 100
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return passthrough(x, alignment);
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}
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