ymandel updated this revision to Diff 419804.
ymandel added a comment.
comment
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D122908/new/
https://reviews.llvm.org/D122908
Files:
clang/lib/Analysis/FlowSensitive/Transfer.cpp
clang/unittests/Analysis/FlowSensitive/TransferTest.cpp
Index: clang/unittests/Analysis/FlowSensitive/TransferTest.cpp
===================================================================
--- clang/unittests/Analysis/FlowSensitive/TransferTest.cpp
+++ clang/unittests/Analysis/FlowSensitive/TransferTest.cpp
@@ -2368,6 +2368,131 @@
});
}
+TEST_F(TransferTest, BuiltinExpect) {
+ std::string Code = R"(
+ void target(long Foo) {
+ long Bar = __builtin_expect(Foo, true);
+ /*[[p]]*/
+ }
+ )";
+ runDataflow(Code,
+ [](llvm::ArrayRef<
+ std::pair<std::string, DataflowAnalysisState<NoopLattice>>>
+ Results,
+ ASTContext &ASTCtx) {
+ ASSERT_THAT(Results, ElementsAre(Pair("p", _)));
+ const auto &Env = Results[0].second.Env;
+
+ const ValueDecl *FooDecl = findValueDecl(ASTCtx, "Foo");
+ ASSERT_THAT(FooDecl, NotNull());
+
+ const ValueDecl *BarDecl = findValueDecl(ASTCtx, "Bar");
+ ASSERT_THAT(BarDecl, NotNull());
+
+ EXPECT_EQ(Env.getValue(*FooDecl, SkipPast::None),
+ Env.getValue(*BarDecl, SkipPast::None));
+ });
+}
+
+TEST_F(TransferTest, BuiltinUnreachable) {
+ std::string Code = R"(
+ void target(bool Foo) {
+ bool Bar = false;
+ if (Foo)
+ Bar = Foo;
+ else
+ __builtin_unreachable();
+ (void)0;
+ /*[[p]]*/
+ }
+ )";
+ runDataflow(Code,
+ [](llvm::ArrayRef<
+ std::pair<std::string, DataflowAnalysisState<NoopLattice>>>
+ Results,
+ ASTContext &ASTCtx) {
+ ASSERT_THAT(Results, ElementsAre(Pair("p", _)));
+ const auto &Env = Results[0].second.Env;
+
+ const ValueDecl *FooDecl = findValueDecl(ASTCtx, "Foo");
+ ASSERT_THAT(FooDecl, NotNull());
+
+ const ValueDecl *BarDecl = findValueDecl(ASTCtx, "Bar");
+ ASSERT_THAT(BarDecl, NotNull());
+
+ // `__builtin_unreachable` promises that the code is
+ // unreachable, so the compiler treats the "then" branch as the
+ // only possible predecessor of this statement.
+ EXPECT_EQ(Env.getValue(*FooDecl, SkipPast::None),
+ Env.getValue(*BarDecl, SkipPast::None));
+ });
+}
+
+TEST_F(TransferTest, BuiltinTrap) {
+ std::string Code = R"(
+ void target(bool Foo) {
+ bool Bar = false;
+ if (Foo)
+ Bar = Foo;
+ else
+ __builtin_trap();
+ (void)0;
+ /*[[p]]*/
+ }
+ )";
+ runDataflow(Code,
+ [](llvm::ArrayRef<
+ std::pair<std::string, DataflowAnalysisState<NoopLattice>>>
+ Results,
+ ASTContext &ASTCtx) {
+ ASSERT_THAT(Results, ElementsAre(Pair("p", _)));
+ const auto &Env = Results[0].second.Env;
+
+ const ValueDecl *FooDecl = findValueDecl(ASTCtx, "Foo");
+ ASSERT_THAT(FooDecl, NotNull());
+
+ const ValueDecl *BarDecl = findValueDecl(ASTCtx, "Bar");
+ ASSERT_THAT(BarDecl, NotNull());
+
+ // `__builtin_trap` ensures program termination, so only the
+ // "then" branch is a predecessor of this statement.
+ EXPECT_EQ(Env.getValue(*FooDecl, SkipPast::None),
+ Env.getValue(*BarDecl, SkipPast::None));
+ });
+}
+
+TEST_F(TransferTest, BuiltinDebugTrap) {
+ std::string Code = R"(
+ void target(bool Foo) {
+ bool Bar = false;
+ if (Foo)
+ Bar = Foo;
+ else
+ __builtin_debugtrap();
+ (void)0;
+ /*[[p]]*/
+ }
+ )";
+ runDataflow(Code,
+ [](llvm::ArrayRef<
+ std::pair<std::string, DataflowAnalysisState<NoopLattice>>>
+ Results,
+ ASTContext &ASTCtx) {
+ ASSERT_THAT(Results, ElementsAre(Pair("p", _)));
+ const auto &Env = Results[0].second.Env;
+
+ const ValueDecl *FooDecl = findValueDecl(ASTCtx, "Foo");
+ ASSERT_THAT(FooDecl, NotNull());
+
+ const ValueDecl *BarDecl = findValueDecl(ASTCtx, "Bar");
+ ASSERT_THAT(BarDecl, NotNull());
+
+ // `__builtin_debugtrap` doesn't ensure program termination.
+ EXPECT_NE(Env.getValue(*FooDecl, SkipPast::None),
+ Env.getValue(*BarDecl, SkipPast::None));
+ });
+}
+
TEST_F(TransferTest, StaticIntSingleVarDecl) {
std::string Code = R"(
void target() {
Index: clang/lib/Analysis/FlowSensitive/Transfer.cpp
===================================================================
--- clang/lib/Analysis/FlowSensitive/Transfer.cpp
+++ clang/lib/Analysis/FlowSensitive/Transfer.cpp
@@ -22,6 +22,7 @@
#include "clang/AST/StmtVisitor.h"
#include "clang/Analysis/FlowSensitive/DataflowEnvironment.h"
#include "clang/Analysis/FlowSensitive/Value.h"
+#include "clang/Basic/Builtins.h"
#include "clang/Basic/OperatorKinds.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/Casting.h"
@@ -444,6 +445,9 @@
}
void VisitCallExpr(const CallExpr *S) {
+ // Of clang's builtins, only `__builtin_expect` is handled explicitly, since
+ // others (like trap, debugtrap, and unreachable) are handled by CFG
+ // construction.
if (S->isCallToStdMove()) {
assert(S->getNumArgs() == 1);
@@ -455,6 +459,18 @@
return;
Env.setStorageLocation(*S, *ArgLoc);
+ } else if (S->getDirectCallee() != nullptr &&
+ S->getDirectCallee()->getBuiltinID() ==
+ Builtin::BI__builtin_expect) {
+ assert(S->getNumArgs() > 0);
+ assert(S->getArg(0) != nullptr);
+ // `__builtin_expect` returns by-value, so strip away any potential
+ // references in the argument.
+ auto *ArgLoc = Env.getStorageLocation(
+ *S->getArg(0)->IgnoreParenImpCasts(), SkipPast::Reference);
+ if (ArgLoc == nullptr)
+ return;
+ Env.setStorageLocation(*S, *ArgLoc);
}
}
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
