diff --git a/clang/lib/Analysis/UninitializedValues.cpp b/clang/lib/Analysis/UninitializedValues.cpp --- a/clang/lib/Analysis/UninitializedValues.cpp +++ b/clang/lib/Analysis/UninitializedValues.cpp @@ -637,6 +637,34 @@ 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 terminator = Pred->getTerminator(); + if (GCCAsmStmt *as = dyn_cast_or_null(terminator.getStmt())) + if (as->isAsmGoto()) { + bool uninitedAfterDecl = false; + for (const auto &o : as->outputs()) { + if (vd != findVar(o).getDecl()) + continue; + for (const auto &label : as->labels()) { + const LabelStmt *ls = label->getLabel()->getStmt(); + if (ls == B->Label) { + uninitedAfterDecl = true; + break; + } + } + if (uninitedAfterDecl) + break; + } + if (uninitedAfterDecl) { + Use.setUninitAfterDecl(); + continue; + } + } + } + unsigned &SV = SuccsVisited[Pred->getBlockID()]; if (!SV) { // When visiting the first successor of a block, mark all NULL @@ -829,7 +857,8 @@ for (const auto &o : as->outputs()) if (const VarDecl *VD = findVar(o).getDecl()) - vals[VD] = Initialized; + if (vals[VD] != Initialized) + vals[VD] = MayUninitialized; } void TransferFunctions::VisitObjCMessageExpr(ObjCMessageExpr *ME) { diff --git a/clang/test/Analysis/uninit-asm-goto.cpp b/clang/test/Analysis/uninit-asm-goto.cpp --- a/clang/test/Analysis/uninit-asm-goto.cpp +++ b/clang/test/Analysis/uninit-asm-goto.cpp @@ -1,6 +1,6 @@ // RUN: %clang_cc1 -std=c++11 -Wuninitialized -verify %s -// expected-no-diagnostics +// test1: Expect no diagnostics int test1(int x) { int y; asm goto("# %0 %1 %2" : "=r"(y) : "r"(x) : : err); @@ -8,3 +8,31 @@ 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 foo(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; +}