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[ubsan] Remove -ubsan-unique-traps (replace with -fno-sanitize-merge) (#120613)
-fno-sanitize-merge (introduced in #120511) duplicates the functionality of -ubsan-unique-traps but also allows individual checks to be specified e.g., * "-fno-sanitize-merge" without arguments is equivalent to -ubsan-unique-traps * "-fno-sanitize-merge=bool,enum" will apply it only to those two checks Additionally, the naming is more consistent with the rest of the -fsanitize- family. This patch therefore removes -ubsan-unique-traps. This breaks backwards compatibility; we hope that this is acceptable since '-mllvm -ubsan-unique-traps' was an experimental flag. This patch also adds negative test examples to bounds-checking.c, and strengthens the NOOPTARRAY assertion to prevent spurious matches. "-bounds-checking-unique-traps" is unaffected by this patch.
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‎clang/docs/ReleaseNotes.rst‎

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@@ -445,6 +445,10 @@ New Compiler Flags
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- The ``-Warray-compare-cxx26`` warning has been added to warn about array comparison
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starting from C++26, this warning is enabled as an error by default.
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- '-fsanitize-merge' (default) and '-fno-sanitize-merge' have been added for
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fine-grained control of which UBSan checks are allowed to be merged by the
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backend (for example, -fno-sanitize-merge=bool,enum).
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Deprecated Compiler Flags
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-------------------------
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@@ -484,6 +488,8 @@ Removed Compiler Flags
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derivatives) is now removed, since it's no longer possible to suppress the
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diagnostic (see above). Users can expect an `unknown warning` diagnostic if
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it's still in use.
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- The experimental flag '-ubsan-unique-traps' has been removed. It is
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superseded by '-fno-sanitize-merge'.
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Attribute Changes in Clang
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--------------------------

‎clang/lib/CodeGen/CGExpr.cpp‎

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@@ -52,11 +52,6 @@
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using namespace clang;
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using namespace CodeGen;
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// Experiment to make sanitizers easier to debug
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static llvm::cl::opt<bool> ClSanitizeDebugDeoptimization(
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"ubsan-unique-traps", llvm::cl::Optional,
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llvm::cl::desc("Deoptimize traps for UBSAN so there is 1 trap per check."));
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// TODO: Introduce frontend options to enabled per sanitizers, similar to
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// `fsanitize-trap`.
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static llvm::cl::opt<bool> ClSanitizeGuardChecks(
@@ -3581,8 +3576,7 @@ static void emitCheckHandlerCall(CodeGenFunction &CGF,
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llvm::AttributeList::FunctionIndex, B),
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/*Local=*/true);
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llvm::CallInst *HandlerCall = CGF.EmitNounwindRuntimeCall(Fn, FnArgs);
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NoMerge = NoMerge || ClSanitizeDebugDeoptimization ||
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!CGF.CGM.getCodeGenOpts().OptimizationLevel ||
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NoMerge = NoMerge || !CGF.CGM.getCodeGenOpts().OptimizationLevel ||
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(CGF.CurCodeDecl && CGF.CurCodeDecl->hasAttr<OptimizeNoneAttr>());
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if (NoMerge)
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HandlerCall->addFnAttr(llvm::Attribute::NoMerge);
@@ -3915,8 +3909,7 @@ void CodeGenFunction::EmitTrapCheck(llvm::Value *Checked,
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llvm::BasicBlock *&TrapBB = TrapBBs[CheckHandlerID];
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NoMerge = NoMerge || ClSanitizeDebugDeoptimization ||
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!CGM.getCodeGenOpts().OptimizationLevel ||
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NoMerge = NoMerge || !CGM.getCodeGenOpts().OptimizationLevel ||
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(CurCodeDecl && CurCodeDecl->hasAttr<OptimizeNoneAttr>());
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if (TrapBB && !NoMerge) {

‎clang/test/CodeGen/bounds-checking.c‎

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@@ -1,7 +1,15 @@
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// RUN: %clang_cc1 -fsanitize=local-bounds -emit-llvm -triple x86_64-apple-darwin10 %s -o - | FileCheck %s
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// RUN: %clang_cc1 -fsanitize=array-bounds -O -fsanitize-trap=array-bounds -emit-llvm -triple x86_64-apple-darwin10 -DNO_DYNAMIC %s -o - | FileCheck %s
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// RUN: %clang_cc1 -fsanitize=local-bounds -fsanitize-trap=local-bounds -O3 -mllvm -bounds-checking-unique-traps -emit-llvm -triple x86_64-apple-darwin10 %s -o - | FileCheck %s --check-prefixes=NOOPTLOCAL
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// RUN: %clang_cc1 -fsanitize=array-bounds -fsanitize-trap=array-bounds -O3 -mllvm -ubsan-unique-traps -emit-llvm -triple x86_64-apple-darwin10 %s -o - | FileCheck %s --check-prefixes=NOOPTARRAY
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// RUN: %clang_cc1 -fsanitize=local-bounds -emit-llvm -triple x86_64-apple-darwin10 %s -o - | FileCheck %s
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// RUN: %clang_cc1 -fsanitize=array-bounds -O -emit-llvm -triple x86_64-apple-darwin10 %s -o - | not FileCheck %s
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// RUN: %clang_cc1 -fsanitize=array-bounds -O -fsanitize-trap=array-bounds -emit-llvm -triple x86_64-apple-darwin10 -DNO_DYNAMIC %s -o - | FileCheck %s
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//
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// RUN: %clang_cc1 -fsanitize=local-bounds -fsanitize-trap=local-bounds -O3 -mllvm -bounds-checking-unique-traps -emit-llvm -triple x86_64-apple-darwin10 %s -o - | FileCheck %s --check-prefixes=NOOPTLOCAL
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// RUN: %clang_cc1 -fsanitize=local-bounds -fsanitize-trap=local-bounds -O3 -emit-llvm -triple x86_64-apple-darwin10 %s -o - | not FileCheck %s --check-prefixes=NOOPTLOCAL
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//
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// N.B. The clang driver defaults to -fsanitize-merge but clang_cc1 effectively
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// defaults to -fno-sanitize-merge.
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// RUN: %clang_cc1 -fsanitize=array-bounds -fsanitize-trap=array-bounds -O3 -emit-llvm -triple x86_64-apple-darwin10 %s -o - | FileCheck %s --check-prefixes=NOOPTARRAY
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// RUN: %clang_cc1 -fsanitize=array-bounds -fsanitize-trap=array-bounds -fno-sanitize-merge -O3 -emit-llvm -triple x86_64-apple-darwin10 %s -o - | FileCheck %s --check-prefixes=NOOPTARRAY
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// RUN: %clang_cc1 -fsanitize=array-bounds -fsanitize-trap=array-bounds -fsanitize-merge=array-bounds -O3 -emit-llvm -triple x86_64-apple-darwin10 %s -o - | not FileCheck %s --check-prefixes=NOOPTARRAY
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//
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// REQUIRES: x86-registered-target
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@@ -43,7 +51,7 @@ int f4(int i) {
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return b[i];
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}
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// Union flexible-array memebers are a C99 extension. All array members with a
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// Union flexible-array members are a C99 extension. All array members with a
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// constant size should be considered FAMs.
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union U { int a[0]; int b[1]; int c[2]; };
@@ -72,13 +80,17 @@ int f7(union U *u, int i) {
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char B[10];
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char B2[10];
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// CHECK-LABEL: @f8
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// Check the label to prevent spuriously matching ubsantraps from other
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// functions.
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// NOOPTLOCAL-LABEL: @f8
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// NOOPTARRAY-LABEL: @f8
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void f8(int i, int k) {
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// NOOPTLOCAL: call void @llvm.ubsantrap(i8 3)
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// NOOPTARRAY: call void @llvm.ubsantrap(i8 18)
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// NOOPTARRAY: call void @llvm.ubsantrap(i8 18) #[[ATTR2:[0-9]+]]
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B[i] = '\0';
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// NOOPTLOCAL: call void @llvm.ubsantrap(i8 5)
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// NOOPTARRAY: call void @llvm.ubsantrap(i8 18)
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// NOOPTARRAY: call void @llvm.ubsantrap(i8 18) #[[ATTR2:[0-9]+]]
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B2[k] = '\0';
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}
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@@ -90,3 +102,4 @@ struct S {
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struct S *f9(int i) {
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return &s[i];
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}
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// NOOPTARRAY: attributes #[[ATTR2]] = { nomerge noreturn nounwind }

‎clang/test/CodeGen/ubsan-trap-merge.c‎

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@@ -10,10 +10,6 @@
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// RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -fsanitize=signed-integer-overflow -O3 %s -o - | FileCheck %s --check-prefixes=HANDLER-NOMERGE
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// RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -fsanitize=signed-integer-overflow -O3 %s -o - -fsanitize-minimal-runtime | FileCheck %s --check-prefixes=MINRT-NOMERGE
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//
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// RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -fsanitize=signed-integer-overflow -O3 -mllvm -ubsan-unique-traps %s -o - -fsanitize-trap=signed-integer-overflow | FileCheck %s --check-prefixes=TRAP-NOMERGE
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// RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -fsanitize=signed-integer-overflow -O3 -mllvm -ubsan-unique-traps %s -o - | FileCheck %s --check-prefixes=HANDLER-NOMERGE
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// RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -fsanitize=signed-integer-overflow -O3 -mllvm -ubsan-unique-traps %s -o - -fsanitize-minimal-runtime | FileCheck %s --check-prefixes=MINRT-NOMERGE
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//
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// RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -fsanitize=signed-integer-overflow -O3 -fno-sanitize-merge=signed-integer-overflow %s -o - -fsanitize-trap=signed-integer-overflow | FileCheck %s --check-prefixes=TRAP-NOMERGE
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// RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -fsanitize=signed-integer-overflow -O3 -fno-sanitize-merge=signed-integer-overflow %s -o - | FileCheck %s --check-prefixes=HANDLER-NOMERGE
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// RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -fsanitize=signed-integer-overflow -O3 -fno-sanitize-merge=signed-integer-overflow %s -o - -fsanitize-minimal-runtime | FileCheck %s --check-prefixes=MINRT-NOMERGE

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