Author: Fangrui Song Date: 2022-06-24T22:15:47-07:00 New Revision: 572b08790a69f955ae0cbb1b4a7d4a215f15dad9
URL: https://github.com/llvm/llvm-project/commit/572b08790a69f955ae0cbb1b4a7d4a215f15dad9 DIFF: https://github.com/llvm/llvm-project/commit/572b08790a69f955ae0cbb1b4a7d4a215f15dad9.diff LOG: [clang] Add back -fsanitize=array-bounds workaround for size-1 array after -fstrict-flex-arrays change Before C99 introduced flexible array member, common practice uses size-1 array to emulate FAM, e.g. https://github.com/python/cpython/issues/94250 As a result, -fsanitize=array-bounds instrumentation skipped such structures as a workaround (from 539e4a77bbabbc19f22b2bd24e04af2e432e599d). D126864 accidentally dropped the workaround. Add it back with tests. Added: clang/test/CodeGen/bounds-checking-fma.c Modified: clang/lib/CodeGen/CGExpr.cpp Removed: ################################################################################ diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp index df96be70800b..0fed82d3e68c 100644 --- a/clang/lib/CodeGen/CGExpr.cpp +++ b/clang/lib/CodeGen/CGExpr.cpp @@ -931,8 +931,8 @@ static llvm::Value *getArrayIndexingBound(CodeGenFunction &CGF, if (const auto *CE = dyn_cast<CastExpr>(Base)) { if (CE->getCastKind() == CK_ArrayToPointerDecay && - !CE->getSubExpr()->isFlexibleArrayMember(Context, - StrictFlexArraysLevel)) { + !CE->getSubExpr()->IgnoreParens()->isFlexibleArrayMember( + Context, std::max(StrictFlexArraysLevel, 1))) { IndexedType = CE->getSubExpr()->getType(); const ArrayType *AT = IndexedType->castAsArrayTypeUnsafe(); if (const auto *CAT = dyn_cast<ConstantArrayType>(AT)) diff --git a/clang/test/CodeGen/bounds-checking-fma.c b/clang/test/CodeGen/bounds-checking-fma.c new file mode 100644 index 000000000000..fbc51dc7a5e1 --- /dev/null +++ b/clang/test/CodeGen/bounds-checking-fma.c @@ -0,0 +1,42 @@ +// REQUIRES: x86-registered-target +// RUN: %clang_cc1 -emit-llvm -triple x86_64 -fsanitize=array-bounds %s -o - | FileCheck %s --check-prefixes=CHECK,CHECK-STRICT-0 +// RUN: %clang_cc1 -emit-llvm -triple x86_64 -fsanitize=array-bounds -fstrict-flex-arrays=1 %s -o - | FileCheck %s --check-prefixes=CHECK,CHECK-STRICT-1 +// RUN: %clang_cc1 -emit-llvm -triple x86_64 -fsanitize=array-bounds -fstrict-flex-arrays=2 %s -o - | FileCheck %s --check-prefixes=CHECK,CHECK-STRICT-2 + +// Before flexible array member was added to C99, many projects use a +// one-element array as the last emember of a structure as an alternative. +// E.g. https://github.com/python/cpython/issues/94250 +// Suppress such errors with -fstrict-flex-arrays=0. +struct One { + int a[1]; +}; +struct Two { + int a[2]; +}; +struct Three { + int a[3]; +}; + +// CHECK-LABEL: define {{.*}} @test_one( +int test_one(struct One *p, int i) { + // CHECK-STRICT-0-NOT: @__ubsan + // CHECK-STRICT-1-NOT: @__ubsan + // CHECK-STRICT-2: call void @__ubsan_handle_out_of_bounds_abort( + return p->a[i] + (p->a)[i]; +} + +// CHECK-LABEL: define {{.*}} @test_two( +int test_two(struct Two *p, int i) { + // CHECK-STRICT-0: call void @__ubsan_handle_out_of_bounds_abort( + // CHECK-STRICT-1: call void @__ubsan_handle_out_of_bounds_abort( + // CHECK-STRICT-2: call void @__ubsan_handle_out_of_bounds_abort( + return p->a[i] + (p->a)[i]; +} + +// CHECK-LABEL: define {{.*}} @test_three( +int test_three(struct Three *p, int i) { + // CHECK-STRICT-0: call void @__ubsan_handle_out_of_bounds_abort( + // CHECK-STRICT-1: call void @__ubsan_handle_out_of_bounds_abort( + // CHECK-STRICT-2: call void @__ubsan_handle_out_of_bounds_abort( + return p->a[i] + (p->a)[i]; +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
