[clang] Fix INF/NAN warning. (PR #80290)
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Fri Feb 2 05:36:03 PST 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang
Author: Zahira Ammarguellat (zahiraam)
<details>
<summary>Changes</summary>
In https://github.com/llvm/llvm-project/pull/76873 a warning was added when the macros INFINITY and NAN are used in binary expressions when -menable-no-nans or -menable-no-infs are used. If the user uses an option that nullifies these two options, the warning will still be generated. This patch adds an additional information to the warning comment to let the user know about this. It also suppresses the warning when #ifdef INFINITY, #ifdef NAN, #ifdef NAN or #ifndef NAN are used in the code.
---
Full diff: https://github.com/llvm/llvm-project/pull/80290.diff
7 Files Affected:
- (modified) clang/include/clang/Basic/DiagnosticCommonKinds.td (+1-1)
- (modified) clang/include/clang/Basic/DiagnosticDocs.td (+7)
- (modified) clang/include/clang/Lex/Preprocessor.h (+6-5)
- (modified) clang/lib/Lex/PPDirectives.cpp (+1-1)
- (modified) clang/lib/Lex/PPExpressions.cpp (+3-1)
- (modified) clang/test/Sema/warn-infinity-nan-disabled-lnx.cpp (+31-7)
- (modified) clang/test/Sema/warn-infinity-nan-disabled-win.cpp (+31-7)
``````````diff
diff --git a/clang/include/clang/Basic/DiagnosticCommonKinds.td b/clang/include/clang/Basic/DiagnosticCommonKinds.td
index b1bada65cb6b2..a9779992a49c2 100644
--- a/clang/include/clang/Basic/DiagnosticCommonKinds.td
+++ b/clang/include/clang/Basic/DiagnosticCommonKinds.td
@@ -73,7 +73,7 @@ def warn_pragma_debug_unexpected_argument : Warning<
def warn_fp_nan_inf_when_disabled : Warning<
"use of %select{infinity|NaN}0%select{| via a macro}1 is undefined behavior "
"due to the currently enabled floating-point options">,
- InGroup<DiagGroup<"nan-infinity-disabled">>;
+ InGroup<DiagGroup<"NanInfDisabledDocs">>;
}
// Parse && Sema
diff --git a/clang/include/clang/Basic/DiagnosticDocs.td b/clang/include/clang/Basic/DiagnosticDocs.td
index e9862422b4997..df153bae4567d 100644
--- a/clang/include/clang/Basic/DiagnosticDocs.td
+++ b/clang/include/clang/Basic/DiagnosticDocs.td
@@ -87,3 +87,10 @@ program by treating all string literals as having type ``const char *``
instead of ``char *``. This can cause unexpected behaviors with type-sensitive
constructs like ``_Generic``.
}];
+
+defvar NanInfDisabledDocs = [{
+This warning is enabled when source code using the macros INFINITY and/or NAN
+is compiled with floating-point options preventing these two values. This can
+lead to undefined behavior. Some command line combinations order and pragmas
+may have an impact and a warning can be generated when not expected.
+}];
diff --git a/clang/include/clang/Lex/Preprocessor.h b/clang/include/clang/Lex/Preprocessor.h
index 9d0d53129a12d..0836b7d439bb0 100644
--- a/clang/include/clang/Lex/Preprocessor.h
+++ b/clang/include/clang/Lex/Preprocessor.h
@@ -2838,7 +2838,8 @@ class Preprocessor {
return AnnotationInfos.find(II)->second;
}
- void emitMacroExpansionWarnings(const Token &Identifier) const {
+ void emitMacroExpansionWarnings(const Token &Identifier,
+ bool IsIfnDef = false) const {
IdentifierInfo *Info = Identifier.getIdentifierInfo();
if (Info->isDeprecatedMacro())
emitMacroDeprecationWarning(Identifier);
@@ -2847,12 +2848,12 @@ class Preprocessor {
!SourceMgr.isInMainFile(Identifier.getLocation()))
emitRestrictExpansionWarning(Identifier);
- if (Info->getName() == "INFINITY")
- if (getLangOpts().NoHonorInfs)
+ if (!IsIfnDef) {
+ if (Info->getName() == "INFINITY" && getLangOpts().NoHonorInfs)
emitRestrictInfNaNWarning(Identifier, 0);
- if (Info->getName() == "NAN")
- if (getLangOpts().NoHonorNaNs)
+ if (Info->getName() == "NAN" && getLangOpts().NoHonorNaNs)
emitRestrictInfNaNWarning(Identifier, 1);
+ }
}
static void processPathForFileMacro(SmallVectorImpl<char> &Path,
diff --git a/clang/lib/Lex/PPDirectives.cpp b/clang/lib/Lex/PPDirectives.cpp
index 9f82a6d073e3b..a980f4bcbae12 100644
--- a/clang/lib/Lex/PPDirectives.cpp
+++ b/clang/lib/Lex/PPDirectives.cpp
@@ -3288,7 +3288,7 @@ void Preprocessor::HandleIfdefDirective(Token &Result,
return;
}
- emitMacroExpansionWarnings(MacroNameTok);
+ emitMacroExpansionWarnings(MacroNameTok, /*IsIfnDef=*/true);
// Check to see if this is the last token on the #if[n]def line.
CheckEndOfDirective(isIfndef ? "ifndef" : "ifdef");
diff --git a/clang/lib/Lex/PPExpressions.cpp b/clang/lib/Lex/PPExpressions.cpp
index 1feb0eb18d71e..8f25c67ec9dfb 100644
--- a/clang/lib/Lex/PPExpressions.cpp
+++ b/clang/lib/Lex/PPExpressions.cpp
@@ -133,7 +133,9 @@ static bool EvaluateDefined(PPValue &Result, Token &PeekTok, DefinedTracker &DT,
Result.Val.setIsUnsigned(false); // Result is signed intmax_t.
DT.IncludedUndefinedIds = !Macro;
- PP.emitMacroExpansionWarnings(PeekTok);
+ PP.emitMacroExpansionWarnings(
+ PeekTok,
+ (II->getName() == "INFINITY" || II->getName() == "NAN") ? true : false);
// If there is a macro, mark it used.
if (Result.Val != 0 && ValueLive)
diff --git a/clang/test/Sema/warn-infinity-nan-disabled-lnx.cpp b/clang/test/Sema/warn-infinity-nan-disabled-lnx.cpp
index 8a610fa0e737e..67a2611374a13 100644
--- a/clang/test/Sema/warn-infinity-nan-disabled-lnx.cpp
+++ b/clang/test/Sema/warn-infinity-nan-disabled-lnx.cpp
@@ -1,13 +1,19 @@
-// RUN: %clang_cc1 -x c++ -verify=no-inf-no-nan -triple powerpc64le-unknown-unknown %s \
-// RUN: -menable-no-infs -menable-no-nans
+// RUN: %clang_cc1 -x c++ -verify=no-inf-no-nan \
+// RUN: -triple powerpc64le-unknown-unknown %s -menable-no-infs \
+// RUN: -menable-no-nans -std=c++23
-// RUN: %clang_cc1 -x c++ -verify=no-fast -triple powerpc64le-unknown-unknown %s
+// RUN: %clang_cc1 -x c++ -verify=no-inf-no-nan \
+// RUN: -triple powerpc64le-unknown-unknown %s -menable-no-infs \
+// RUN: -menable-no-nans -funsafe-math-optimizations -std=c++23
+
+// RUN: %clang_cc1 -x c++ -verify=no-fast -triple powerpc64le-unknown-unknown \
+// RUN: %s -std=c++23
// RUN: %clang_cc1 -x c++ -verify=no-inf -triple powerpc64le-unknown-unknown %s \
-// RUN: -menable-no-infs
+// RUN: -menable-no-infs -std=c++23
// RUN: %clang_cc1 -x c++ -verify=no-nan -triple powerpc64le-unknown-unknown %s \
-// RUN: -menable-no-nans
+// RUN: -menable-no-nans -std=c++23
// no-fast-no-diagnostics
@@ -133,13 +139,31 @@ int compareit(float a, float b) {
// no-inf-warning at +1 {{use of infinity is undefined behavior due to the currently enabled floating-point options}}
p = __builtin_isfinite(a);
- // These should NOT warn, since they are not using NaN or infinity.
+// These should NOT warn, since they are not using NaN or infinity.
j = a > 1.1;
j = b < 1.1;
j = a >= 1.1;
j = b <= 1.1;
j = isunorderedf(a, b);
+#ifndef INFINITY
+ j = a;
+#endif
+#ifndef NAN
+ j = b;
+#endif
+#ifdef INFINITY
+ j = a;
+#endif
+#ifdef NAN
+ j = b;
+#endif
+#if defined(INFINITY)
+ j = a;
+#elifndef(INFINITY)
+ j = b;
+#endif
+
// no-inf-no-nan-warning at +4 {{use of NaN via a macro is undefined behavior due to the currently enabled floating-point options}}
// no-inf-no-nan-warning at +3 {{use of NaN is undefined behavior due to the currently enabled floating-point options}}
// no-nan-warning at +2 {{use of NaN via a macro is undefined behavior due to the currently enabled floating-point options}}
@@ -173,4 +197,4 @@ int compareit(float a, float b) {
j = numeric_limits<float>::infinity();
return 0;
-}
+}
diff --git a/clang/test/Sema/warn-infinity-nan-disabled-win.cpp b/clang/test/Sema/warn-infinity-nan-disabled-win.cpp
index 19a575386e329..a904cfbd04f75 100644
--- a/clang/test/Sema/warn-infinity-nan-disabled-win.cpp
+++ b/clang/test/Sema/warn-infinity-nan-disabled-win.cpp
@@ -1,16 +1,22 @@
// Use of NAN macro will trigger a warning "infinity defined in macro" because
// on Windows the NAN macro is defined using INFINITY. See below.
-// RUN: %clang_cc1 -x c++ -verify=no-inf-no-nan -triple powerpc64le-unknown-unknown %s \
-// RUN: -menable-no-infs -menable-no-nans
+// RUN: %clang_cc1 -x c++ -verify=no-inf-no-nan \
+// RUN: -triple powerpc64le-unknown-unknown %s -menable-no-infs \
+// RUN: -menable-no-nans -std=c++23
-// RUN: %clang_cc1 -x c++ -verify=no-fast -triple powerpc64le-unknown-unknown %s
+// RUN: %clang_cc1 -x c++ -verify=no-inf-no-nan \
+// RUN: -triple powerpc64le-unknown-unknown %s -menable-no-infs \
+// RUN: -menable-no-nans -funsafe-math-optimizations -std=c++23
+
+// RUN: %clang_cc1 -x c++ -verify=no-fast -triple powerpc64le-unknown-unknown \
+// RUN: %s -std=c++23
// RUN: %clang_cc1 -x c++ -verify=no-inf -triple powerpc64le-unknown-unknown %s \
-// RUN: -menable-no-infs
+// RUN: -menable-no-infs -std=c++23
// RUN: %clang_cc1 -x c++ -verify=no-nan -triple powerpc64le-unknown-unknown %s \
-// RUN: -menable-no-nans
+// RUN: -menable-no-nans -std=c++23
// no-fast-no-diagnostics
@@ -136,13 +142,31 @@ int compareit(float a, float b) {
// no-inf-warning at +1 {{use of infinity is undefined behavior due to the currently enabled floating-point options}}
p = __builtin_isfinite(a);
- // These should NOT warn, since they are not using NaN or infinity.
+// These should NOT warn, since they are not using NaN or infinity.
j = a > 1.1;
j = b < 1.1;
j = a >= 1.1;
j = b <= 1.1;
j = isunorderedf(a, b);
+#ifndef INFINITY
+ j = a;
+#endif
+#ifndef NAN
+ j = b;
+#endif
+#ifdef INFINITY
+ j = a;
+#endif
+#ifdef NAN
+ j = b;
+#endif
+#if defined(INFINITY)
+ j = a;
+#elifndef(INFINITY)
+ j = b;
+#endif
+
// no-inf-no-nan-warning at +4 {{use of infinity via a macro is undefined behavior due to the currently enabled floating-point option}}
// no-inf-no-nan-warning at +3 {{use of NaN via a macro is undefined behavior due to the currently enabled floating-point options}}
// no-inf-warning at +2 {{use of infinity via a macro is undefined behavior due to the currently enabled floating-point options}}
@@ -176,4 +200,4 @@ int compareit(float a, float b) {
j = numeric_limits<float>::infinity();
return 0;
-}
+}
``````````
</details>
https://github.com/llvm/llvm-project/pull/80290
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