https://github.com/bjope updated https://github.com/llvm/llvm-project/pull/68590
From 44eedec9dae39e72d5474426a15a07d9be4144fc Mon Sep 17 00:00:00 2001
From: Bjorn Pettersson <bjorn.a.petters...@ericsson.com>
Date: Mon, 9 Oct 2023 16:13:39 +0200
Subject: [PATCH 1/2] [Sema] Handle large shift counts in GetExprRange
GetExprRange did not expect that very large shift counts when
narrowing the range based on logical right shifts. So with inputs
such as
*a >> 123456789012345678901uwb
it would hit assertions about trying to convert a too large APInt
into uint64_t.
This patch fixes that by using the APInt value when determining if
we should reduce the range by the shift count or not.
---
clang/lib/Sema/SemaChecking.cpp | 5 ++---
clang/test/Sema/c2x-expr-range.c | 20 ++++++++++++++++++++
2 files changed, 22 insertions(+), 3 deletions(-)
create mode 100644 clang/test/Sema/c2x-expr-range.c
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 3932d9cd07d9864..eb4d8d2e2806bcb 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -13554,11 +13554,10 @@ static IntRange GetExprRange(ASTContext &C, const
Expr *E, unsigned MaxWidth,
if (std::optional<llvm::APSInt> shift =
BO->getRHS()->getIntegerConstantExpr(C)) {
if (shift->isNonNegative()) {
- unsigned zext = shift->getZExtValue();
- if (zext >= L.Width)
+ if (shift->uge(L.Width))
L.Width = (L.NonNegative ? 0 : 1);
else
- L.Width -= zext;
+ L.Width -= shift->getZExtValue();
}
}
diff --git a/clang/test/Sema/c2x-expr-range.c b/clang/test/Sema/c2x-expr-range.c
new file mode 100644
index 000000000000000..1690a6280386bd5
--- /dev/null
+++ b/clang/test/Sema/c2x-expr-range.c
@@ -0,0 +1,20 @@
+// RUN: %clang_cc1 -verify -fsyntax-only -std=c2x -triple=x86_64-unknown-linux
%s
+
+// test1 used to hit an assertion failure like this during parsing:
+// clang: ../include/llvm/ADT/APInt.h:1488: uint64_t
llvm::APInt::getZExtValue() const: Assertion `getActiveBits() <= 64 && "Too
many bits for uint64_t"' failed.
+// With a stack trace like this leading up to the assert:
+//
+// #9 0x00005645bca16518 GetExprRange(clang::ASTContext&, clang::Expr const*,
unsigned int, bool, bool) SemaChecking.cpp:0:0
+// #10 0x00005645bca048a8 AnalyzeImplicitConversions(clang::Sema&,
clang::Expr*, clang::SourceLocation, bool) SemaChecking.cpp:0:0
+// #11 0x00005645bca06af1 clang::Sema::CheckCompletedExpr(clang::Expr*,
clang::SourceLocation, bool)
+//
+void test1(int *a)
+{
+ (void)(*a >> 123456789012345678901uwb <= 0); // expected-warning {{shift
count >= width of type}}
+}
+
+// Same as above but using __uint128_t instead of __BitInt.
+void test2(__uint128_t *a)
+{
+ (void)(*a >> ((__uint128_t)__UINT64_MAX__ + (__uint128_t)1) <= 0); //
expected-warning {{shift count >= width of type}}
+}
From f8881531c6b5f8a7f71554c01c4e7df8e24e7f72 Mon Sep 17 00:00:00 2001
From: Bjorn Pettersson <bjorn.a.petters...@ericsson.com>
Date: Mon, 9 Oct 2023 17:34:41 +0200
Subject: [PATCH 2/2] [Sema] Handle large shift counts in GetExprRange
GetExprRange did not expect that very large shift counts when
narrowing the range based on logical right shifts. So with inputs
such as
*a >> 123456789012345678901uwb
it would hit assertions about trying to convert a too large APInt
into uint64_t.
This patch fixes that by using the APInt value when determining if
we should reduce the range by the shift count or not.
---
clang/docs/ReleaseNotes.rst | 4 ++++
clang/test/Sema/c2x-expr-range.c | 14 +++++---------
2 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 2d0302c399fb6f3..45ee6db4112b978 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -219,6 +219,10 @@ Bug Fixes in This Version
- Clang no longer considers the loss of ``__unaligned`` qualifier from objects
as
an invalid conversion during method function overload resolution.
+- Fixed an issue when a shift count larger than ``__INT64_MAX__``, in a right
+ shift operation, could result in missing warnings about
+ ``shift count >= width of type`` or internal compiler error.
+
Bug Fixes to Compiler Builtins
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/test/Sema/c2x-expr-range.c b/clang/test/Sema/c2x-expr-range.c
index 1690a6280386bd5..0fe1bc547bbd353 100644
--- a/clang/test/Sema/c2x-expr-range.c
+++ b/clang/test/Sema/c2x-expr-range.c
@@ -1,19 +1,15 @@
// RUN: %clang_cc1 -verify -fsyntax-only -std=c2x -triple=x86_64-unknown-linux
%s
-// test1 used to hit an assertion failure like this during parsing:
-// clang: ../include/llvm/ADT/APInt.h:1488: uint64_t
llvm::APInt::getZExtValue() const: Assertion `getActiveBits() <= 64 && "Too
many bits for uint64_t"' failed.
-// With a stack trace like this leading up to the assert:
-//
-// #9 0x00005645bca16518 GetExprRange(clang::ASTContext&, clang::Expr const*,
unsigned int, bool, bool) SemaChecking.cpp:0:0
-// #10 0x00005645bca048a8 AnalyzeImplicitConversions(clang::Sema&,
clang::Expr*, clang::SourceLocation, bool) SemaChecking.cpp:0:0
-// #11 0x00005645bca06af1 clang::Sema::CheckCompletedExpr(clang::Expr*,
clang::SourceLocation, bool)
-//
+// Regression test for bug where we used to hit assertion due to shift amount
+// being larger than 64 bits. We want to see a warning about too large shift
+// amount.
void test1(int *a)
{
(void)(*a >> 123456789012345678901uwb <= 0); // expected-warning {{shift
count >= width of type}}
}
-// Same as above but using __uint128_t instead of __BitInt.
+// Similar to test1 above, but using __uint128_t instead of __BitInt.
+// We want to see a warning about too large shift amount.
void test2(__uint128_t *a)
{
(void)(*a >> ((__uint128_t)__UINT64_MAX__ + (__uint128_t)1) <= 0); //
expected-warning {{shift count >= width of type}}
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