nickdesaulniers created this revision.
nickdesaulniers added reviewers: void, jyknight, jyu2, efriedma.
nickdesaulniers requested review of this revision.
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When performing CFG based analyses, don't forget to check the child
statements of an asm goto, such as the expressions used for
inputs+outputs.
Fixes: https://github.com/llvm/llvm-project/issues/51024
Fixes: https://github.com/ClangBuiltLinux/linux/issues/1439
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D116059
Files:
clang/lib/Analysis/CFG.cpp
clang/lib/Analysis/UninitializedValues.cpp
clang/test/Analysis/asm-goto.cpp
Index: clang/test/Analysis/asm-goto.cpp
===================================================================
--- clang/test/Analysis/asm-goto.cpp
+++ clang/test/Analysis/asm-goto.cpp
@@ -1,5 +1,5 @@
-// RUN: %clang_analyze_cc1 -triple i386-pc-linux-gnu -analyzer-checker=debug.DumpCFG %s 2>&1 | FileCheck %s
-// RUN: %clang_analyze_cc1 -triple x86_64-pc-linux-gnu -analyzer-checker=debug.DumpCFG %s 2>&1 | FileCheck %s
+// RUN: %clang_analyze_cc1 -triple i386-pc-linux-gnu -analyzer-checker=debug.DumpCFG %s 2>&1 | FileCheck %s
+// RUN: %clang_analyze_cc1 -triple x86_64-pc-linux-gnu -analyzer-checker=debug.DumpCFG %s 2>&1 | FileCheck %s
int foo(int cond)
{
@@ -17,11 +17,13 @@
// CHECK-NEXT: Succs (1): B0
// CHECK-LABEL: label_true
+// CHECK-NEXT: cond
+// CHECK-NEXT: [B3.1]
// CHECK-NEXT: asm goto
+// CHECK-NEXT: T: [B3.3]
// CHECK-NEXT: Preds (2): B3 B4
// CHECK-NEXT: Succs (3): B2 B3 B1
-
int bar(int cond)
{
asm goto("testl %0, %0; jne %l1;" :: "r"(cond)::L1, L2);
@@ -32,7 +34,10 @@
}
// CHECK: [B4]
+// CHECK-NEXT: cond
+// CHECK-NEXT: [B4.1]
// CHECK-NEXT: asm goto
+// CHECK-NEXT: T: [B4.3]
// CHECK-NEXT: Preds (1): B5
// CHECK-NEXT: Succs (3): B3 B2 B1
@@ -48,6 +53,22 @@
}
// CHECK-LABEL: A1
+// CHECK-NEXT: n
+// CHECK-NEXT: [B4.1]
// CHECK-NEXT: asm goto
+// CHECK-NEXT: T: [B4.3]
// CHECK-NEXT: Preds (2): B5 B4
// CHECK-NEXT: Succs (5): B3 B4 B2 B1 B5
+
+void baz(void)
+{
+ asm goto("" :: "r"(1 ? 2 : 0 << -1) :: error);
+error:;
+}
+
+// CHECK: [B2]
+// CHECK-NEXT: 1: [B5.2] ? [B3.1] : [B4.4]
+// CHECK-NEXT: 2: asm goto ("" : : "r" ([B2.1]) : : error);
+// CHECK-NEXT: T: [B2.2]
+// CHECK-NEXT: Preds (2): B3 B4
+// CHECK-NEXT: Succs (1): B1
Index: clang/lib/Analysis/UninitializedValues.cpp
===================================================================
--- clang/lib/Analysis/UninitializedValues.cpp
+++ clang/lib/Analysis/UninitializedValues.cpp
@@ -820,10 +820,10 @@
Ex = stripCasts(C, UO->getSubExpr());
if (const VarDecl *VD = findVar(Ex).getDecl())
- if (vals[VD] != Initialized)
- // If the variable isn't initialized by the time we get here, then we
- // mark it as potentially uninitialized for those cases where it's used
- // on an indirect path, where it's not guaranteed to be defined.
+ if (vals[VD] == Initialized)
+ // If the variable is initialized by the time we get here, then we mark
+ // it as potentially uninitialized for those cases where it's used on
+ // an indirect path, where it's not guaranteed to be defined.
vals[VD] = MayUninitialized;
}
}
Index: clang/lib/Analysis/CFG.cpp
===================================================================
--- clang/lib/Analysis/CFG.cpp
+++ clang/lib/Analysis/CFG.cpp
@@ -3340,23 +3340,23 @@
CFGBlock *CFGBuilder::VisitGCCAsmStmt(GCCAsmStmt *G, AddStmtChoice asc) {
// Goto is a control-flow statement. Thus we stop processing the current
// block and create a new one.
+ if (G->isAsmGoto()) {
+ if (Block) {
+ Succ = Block;
+ if (badCFG)
+ return nullptr;
+ }
- if (!G->isAsmGoto())
- return VisitStmt(G, asc);
-
- if (Block) {
- Succ = Block;
- if (badCFG)
- return nullptr;
+ Block = createBlock();
+ Block->setTerminator(G);
+ // We will backpatch this block later for all the labels.
+ BackpatchBlocks.push_back(JumpSource(Block, ScopePos));
+ // Save "Succ" in BackpatchBlocks. In the backpatch processing, "Succ" is
+ // used to avoid adding "Succ" again.
+ BackpatchBlocks.push_back(JumpSource(Succ, ScopePos));
}
- Block = createBlock();
- Block->setTerminator(G);
- // We will backpatch this block later for all the labels.
- BackpatchBlocks.push_back(JumpSource(Block, ScopePos));
- // Save "Succ" in BackpatchBlocks. In the backpatch processing, "Succ" is
- // used to avoid adding "Succ" again.
- BackpatchBlocks.push_back(JumpSource(Succ, ScopePos));
- return Block;
+
+ return VisitStmt(G, asc);
}
CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) {
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