822f74a911
This patch contains a number of changes relating to the above flag;
primarily it updates comment references to the old flag names,
"-fextend-lifetimes" and "-fextend-this-ptr" to refer to the new names,
"-fextend-variable-liveness[={all,this}]". These changes are all NFC.
This patch also removes the explicit -fextend-this-ptr-liveness flag
alias, and shortens the help-text for the main flag; these are both
changes that were meant to be applied in the initial PR (#110000), but
due to some user-error on my part they were not included in the merged
commit.
62 lines
2.4 KiB
C++
62 lines
2.4 KiB
C++
// RUN: %clang_cc1 %s -triple x86_64-unknown-linux-gnu -emit-llvm -fextend-variable-liveness -fsanitize=null -fsanitize-trap=null -o - | FileCheck --check-prefixes=CHECK,NULL --implicit-check-not=ubsantrap %s
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// RUN: %clang_cc1 %s -triple x86_64-unknown-linux-gnu -emit-llvm -fextend-variable-liveness -o - | FileCheck %s
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// With -fextend-variable-liveness, the compiler previously generated a fake.use of any
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// reference variable at the end of the scope in which its alloca exists. This
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// caused two issues, where we would get fake uses for uninitialized variables
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// if that variable was declared after an early-return, and UBSan's null checks
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// would complain about this.
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// This test verifies that UBSan does not produce null-checks for arguments to
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// llvm.fake.use, and that fake uses are not emitted for a variable on paths
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// it has not been declared.
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struct A { short s1, s2; };
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extern long& getA();
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void foo()
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{
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auto& va = getA();
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if (va < 5)
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return;
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auto& vb = getA();
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}
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// CHECK-LABEL: define{{.*}}foo
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// CHECK: [[VA_CALL:%.+]] = call{{.*}} ptr @_Z4getAv()
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/// We check here for the first UBSan check for "va".
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// NULL: [[VA_ISNULL:%.+]] = icmp ne ptr [[VA_CALL]], null
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// NULL: br i1 [[VA_ISNULL]], label %{{[^,]+}}, label %[[VA_TRAP:[^,]+]]
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// NULL: [[VA_TRAP]]:
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// NULL: call void @llvm.ubsantrap(
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// CHECK: [[VA_PTR:%.+]] = load ptr, ptr %va
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// CHECK-NEXT: [[VA_CMP:%.+]] = load i64, ptr [[VA_PTR]]
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// CHECK-NEXT: [[VA_CMP_RES:%.+]] = icmp slt i64 [[VA_CMP]], 5
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// CHECK-NEXT: br i1 [[VA_CMP_RES]], label %[[EARLY_EXIT:[^,]+]], label %[[NOT_EARLY_EXIT:[^,]+]]
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// CHECK: [[EARLY_EXIT]]:
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// CHECK: br label %cleanup
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/// The fake use for "vb" only appears on the path where its declaration is
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/// reached.
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// CHECK: [[NOT_EARLY_EXIT]]:
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// CHECK: [[VB_CALL:%.+]] = call{{.*}} ptr @_Z4getAv()
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/// We check here for the second UBSan check for "vb".
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// NULL: [[VB_ISNULL:%.+]] = icmp ne ptr [[VB_CALL]], null
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// NULL: br i1 [[VB_ISNULL]], label %{{[^,]+}}, label %[[VB_TRAP:[^,]+]]
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// NULL: [[VB_TRAP]]:
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// NULL: call void @llvm.ubsantrap(
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// CHECK: [[VB_FAKE_USE:%.+]] = load ptr, ptr %vb
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// CHECK-NEXT: call void (...) @llvm.fake.use(ptr [[VB_FAKE_USE]])
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// CHECK: br label %cleanup
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// CHECK: cleanup:
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// CHECK: [[VA_FAKE_USE:%.+]] = load ptr, ptr %va
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// CHECK-NEXT: call void (...) @llvm.fake.use(ptr [[VA_FAKE_USE]])
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// NULL: declare void @llvm.ubsantrap
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