void updated this revision to Diff 244844.
void added a comment.
Herald added a subscriber: martong.
Use "auto" and change labels to clarify test.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D71314/new/
https://reviews.llvm.org/D71314
Files:
clang/lib/Analysis/UninitializedValues.cpp
clang/test/Analysis/uninit-asm-goto.cpp
Index: clang/test/Analysis/uninit-asm-goto.cpp
===================================================================
--- /dev/null
+++ clang/test/Analysis/uninit-asm-goto.cpp
@@ -0,0 +1,59 @@
+// RUN: %clang_cc1 -std=c++11 -Wuninitialized -verify %s
+
+// test1: Expect no diagnostics
+int test1(int x) {
+ int y;
+ asm goto("# %0 %1 %2" : "=r"(y) : "r"(x) : : err);
+ return y;
+ err:
+ return -1;
+}
+
+int test2(int x) {
+ int y; // expected-warning {{variable 'y' is used uninitialized whenever its declaration is reached}} \
+ // expected-note {{initialize the variable}}
+ if (x < 42)
+ asm volatile goto("testl %0, %0; testl %1, %2; jne %l3" : "+S"(x), "+D"(y) : "r"(x) :: indirect_1, indirect_2);
+ else
+ asm volatile goto("testl %0, %1; testl %2, %3; jne %l5" : "+S"(x), "+D"(y) : "r"(x), "r"(y) :: indirect_1, indirect_2);
+ return x + y;
+indirect_1:
+ return -42;
+indirect_2:
+ return y; // expected-note {{uninitialized use occurs here}}
+}
+
+int test3(int x) {
+ int y; // expected-warning {{variable 'y' is used uninitialized whenever its declaration is reached}} \
+ // expected-note {{initialize the variable}}
+ asm goto("xorl %1, %0; jmp %l2" : "=&r"(y) : "r"(x) : : fail);
+normal:
+ y += x;
+ return y;
+ if (x) {
+fail:
+ return y; // expected-note {{uninitialized use occurs here}}
+ }
+ return 0;
+}
+
+int test4(int x) {
+ int y; // expected-warning {{variable 'y' is used uninitialized whenever its declaration is reached}} \
+ // expected-note {{initialize the variable}}
+ goto forward;
+backward:
+ return y; // expected-note {{uninitialized use occurs here}}
+forward:
+ asm goto("# %0 %1 %2" : "=r"(y) : "r"(x) : : backward);
+ return y;
+}
+
+// test5: Expect no diagnostics
+int test5(int x) {
+ int y;
+ asm volatile goto("testl %0, %0; testl %1, %2; jne %l3" : "+S"(x), "+D"(y) : "r"(x) :: fallthrough_1, fallthrough_2);
+fallthrough_1:
+ return y;
+fallthrough_2:
+ return -2;
+}
Index: clang/lib/Analysis/UninitializedValues.cpp
===================================================================
--- clang/lib/Analysis/UninitializedValues.cpp
+++ clang/lib/Analysis/UninitializedValues.cpp
@@ -575,6 +575,28 @@
continue;
}
+ if (AtPredExit == MayUninitialized) {
+ // If the predecessor's terminator is an "asm goto" that initializes
+ // the variable, then it won't be counted as "initialized" on the
+ // non-fallthrough paths.
+ CFGTerminator term = Pred->getTerminator();
+ if (const auto *as = dyn_cast_or_null<GCCAsmStmt>(term.getStmt())) {
+ const CFGBlock *fallthrough = *Pred->succ_begin();
+ if (as->isAsmGoto() &&
+ llvm::any_of(as->outputs(), [&](const Expr *output) {
+ return vd == findVar(output).getDecl() &&
+ llvm::any_of(as->labels(),
+ [&](const AddrLabelExpr *label) {
+ return label->getLabel()->getStmt() == B->Label &&
+ B != fallthrough;
+ });
+ })) {
+ Use.setUninitAfterDecl();
+ continue;
+ }
+ }
+ }
+
unsigned &SV = SuccsVisited[Pred->getBlockID()];
if (!SV) {
// When visiting the first successor of a block, mark all NULL
@@ -760,6 +782,17 @@
}
}
+void TransferFunctions::VisitGCCAsmStmt(GCCAsmStmt *as) {
+ // An "asm goto" statement is a terminator that may initialize some variables.
+ if (!as->isAsmGoto())
+ return;
+
+ for (const auto &o : as->outputs())
+ if (const auto *VD = findVar(o).getDecl())
+ if (vals[VD] != Initialized)
+ vals[VD] = MayUninitialized;
+}
+
void TransferFunctions::VisitObjCMessageExpr(ObjCMessageExpr *ME) {
// If the Objective-C message expression is an implicit no-return that
// is not modeled in the CFG, set the tracked dataflow values to Unknown.
@@ -797,6 +830,10 @@
if (Optional<CFGStmt> cs = I.getAs<CFGStmt>())
tf.Visit(const_cast<Stmt *>(cs->getStmt()));
}
+ CFGTerminator terminator = block->getTerminator();
+ if (const auto *as = dyn_cast_or_null<GCCAsmStmt>(terminator.getStmt()))
+ if (as->isAsmGoto())
+ tf.Visit(as);
return vals.updateValueVectorWithScratch(block);
}
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