https://github.com/pskrgag created
https://github.com/llvm/llvm-project/pull/109838
Since b1e4656e8ee3289dc5f3139fc8eb33152f96bfe6 it's possible to pass `Stmt`
into `invalidateRegions`(). Use it in `VisitGCCAsmStmt` to invalidate regions
passed as in and out arguments for inline assembly.
This also fixes #109836 issue with FP uninitialized read, since
`invalidateRegions()` invalidates super region as well, so there won't be
problems with binding only to first element of the array.
Closes #109836
>From dbec0e8368157684f9efc63a556037ba31d5f2ea Mon Sep 17 00:00:00 2001
From: Pavel Skripkin <paskrip...@gmail.com>
Date: Tue, 24 Sep 2024 20:18:30 +0300
Subject: [PATCH] clang/csa: use invalidateRegions() in VisitGCCAsmStmt
---
clang/lib/StaticAnalyzer/Core/ExprEngine.cpp | 8 +++++--
clang/test/Analysis/asm.cpp | 22 ++++++++++++++++----
2 files changed, 24 insertions(+), 6 deletions(-)
diff --git a/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
b/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
index fdabba46992b08..a1a015715b4c8b 100644
--- a/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
+++ b/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
@@ -3810,7 +3810,9 @@ void ExprEngine::VisitGCCAsmStmt(const GCCAsmStmt *A,
ExplodedNode *Pred,
assert(!isa<NonLoc>(X)); // Should be an Lval, or unknown, undef.
if (std::optional<Loc> LV = X.getAs<Loc>())
- state = state->bindLoc(*LV, UnknownVal(), Pred->getLocationContext());
+ state = state->invalidateRegions(*LV, A, currBldrCtx->blockCount(),
+ Pred->getLocationContext(),
+ /*CausedByPointerEscape=*/true);
}
// Do not reason about locations passed inside inline assembly.
@@ -3818,7 +3820,9 @@ void ExprEngine::VisitGCCAsmStmt(const GCCAsmStmt *A,
ExplodedNode *Pred,
SVal X = state->getSVal(I, Pred->getLocationContext());
if (std::optional<Loc> LV = X.getAs<Loc>())
- state = state->bindLoc(*LV, UnknownVal(), Pred->getLocationContext());
+ state = state->invalidateRegions(*LV, A, currBldrCtx->blockCount(),
+ Pred->getLocationContext(),
+ /*CausedByPointerEscape=*/true);
}
Bldr.generateNode(A, Pred, state);
diff --git a/clang/test/Analysis/asm.cpp b/clang/test/Analysis/asm.cpp
index e0691dc4d794f5..b77038b2e83db7 100644
--- a/clang/test/Analysis/asm.cpp
+++ b/clang/test/Analysis/asm.cpp
@@ -10,8 +10,10 @@ void testRValueOutput() {
int &ref = global;
ref = 1;
__asm__("" : "=r"(((int)(global)))); // don't crash on rvalue output operand
- clang_analyzer_eval(global == 1); // expected-warning{{UNKNOWN}}
- clang_analyzer_eval(ref == 1); // expected-warning{{UNKNOWN}}
+ clang_analyzer_eval(global == 1); // expected-warning{{FALSE}}
+ // expected-warning@-1{{TRUE}}
+ clang_analyzer_eval(ref == 1); // expected-warning{{FALSE}}
+ // expected-warning@-1{{TRUE}}
}
void *MyMemcpy(void *d, const void *s, const int n) {
@@ -40,7 +42,19 @@ void testInlineAsmMemcpyUninit(void)
{
int a[10], b[10] = {}, c;
MyMemcpy(&a[1], &b[1], sizeof(b) - sizeof(b[1]));
- c = a[0]; // expected-warning{{Assigned value is garbage or undefined}}
+ c = a[0]; // FIXME: should be warning about uninitialized value, but
invalidateRegions() also
+ // invalidates super region.
+}
+
+void testInlineAsmMemcpyUninitLoop(const void *src, unsigned long len)
+{
+ int a[10], c;
+ unsigned long toCopy = sizeof(a) < len ? sizeof(a) : len;
+
+ MyMemcpy(&a, src, toCopy);
+
+ for (unsigned long i = 0; i < toCopy; ++i)
+ c = a[i]; // no-warning
}
void testAsmWithVoidPtrArgument()
@@ -49,6 +63,6 @@ void testAsmWithVoidPtrArgument()
clang_analyzer_dump(*(int *)globalVoidPtr); // expected-warning-re
{{reg_${{[0-9]+}}<int Element{SymRegion{reg_${{[0-9]+}}<void *
globalVoidPtr>},0 S64b,int}>}}
clang_analyzer_dump_ptr(globalVoidPtr); // expected-warning-re
{{&SymRegion{reg_${{[0-9]+}}<void * globalVoidPtr>}}}
asm ("" : : "a"(globalVoidPtr)); // no crash
- clang_analyzer_dump(*(int *)globalVoidPtr); // expected-warning {{Unknown}}
+ clang_analyzer_dump(*(int *)globalVoidPtr); // expected-warning
{{derived_$3{conj_$2{int, LC1, S2385, #1},Element{SymRegion{reg_$0<void *
globalVoidPtr>},0 S64b,int}}}}
clang_analyzer_dump_ptr(globalVoidPtr); // expected-warning-re
{{&SymRegion{reg_${{[0-9]+}}<void * globalVoidPtr>}}}
}
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