From 64037afe014e241e1c642952a703b6031d17d5a5 Mon Sep 17 00:00:00 2001
From: Reid Kleckner <rnk@google.com>
Date: Thu, 10 Feb 2022 13:40:28 -0800
Subject: [PATCH] [CodeView] Avoid integer overflow while parsing long version
 strings

This came up on a funny vendor-provided version string that didn't have
a standard dotted quad of numbers.
---
 llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp |  3 +-
 .../COFF/compiler-version-overflow.ll         | 36 +++++++++++++++++++
 2 files changed, 38 insertions(+), 1 deletion(-)
 create mode 100644 llvm/test/DebugInfo/COFF/compiler-version-overflow.ll

diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
index 52c74713551..6cc30ebe5ce 100644
--- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -826,6 +826,8 @@ static Version parseVersion(StringRef Name) {
     if (isdigit(C)) {
       V.Part[N] *= 10;
       V.Part[N] += C - '0';
+      V.Part[N] =
+          std::min<int>(V.Part[N], std::numeric_limits<uint16_t>::max());
     } else if (C == '.') {
       ++N;
       if (N >= 4)
@@ -867,7 +869,6 @@ void CodeViewDebug::emitCompilerInformation() {
   Version FrontVer = parseVersion(CompilerVersion);
   OS.AddComment("Frontend version");
   for (int N : FrontVer.Part) {
-    N = std::min<int>(N, std::numeric_limits<uint16_t>::max());
     OS.emitInt16(N);
   }
 
diff --git a/llvm/test/DebugInfo/COFF/compiler-version-overflow.ll b/llvm/test/DebugInfo/COFF/compiler-version-overflow.ll
new file mode 100644
index 00000000000..538ba699ae6
--- /dev/null
+++ b/llvm/test/DebugInfo/COFF/compiler-version-overflow.ll
@@ -0,0 +1,36 @@
+; RUN: llc -filetype=obj -mtriple i686-pc-windows-msvc %s -o %t.o
+; RUN: llvm-pdbutil dump %t.o -symbols | FileCheck %s
+
+; CHECK: {{.*}} | S_COMPILE3 [size = {{.*}}]
+; CHECK-NEXT: machine = intel pentium 3, Ver = clang version 999999999999.9999999999.9999999.99999999 , language = c++
+; CHECK-NEXT: frontend = 65535.65535.65535.65535, backend = 15000.0.0.0
+; CHECK-NEXT: flags = none
+
+
+; ModuleID = 'D:\src\scopes\foo.cpp'
+source_filename = "D:\5Csrc\5Cscopes\5Cfoo.cpp"
+target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32"
+target triple = "i686-pc-windows-msvc19.0.23918"
+
+define i32 @"?foo@@YAHXZ"() !dbg !10 {
+entry:
+  ret i32 42, !dbg !14
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!7, !8}
+!llvm.ident = !{!9}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 999999999999.9999999999.9999999.99999999 ", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
+; One .debug$S section should contain an S_COMPILE3 record that identifies the
+; source language and the version of the compiler based on the DICompileUnit.
+!1 = !DIFile(filename: "D:\5Csrc\5Cscopes\5Cfoo.cpp", directory: "D:\5Csrc\5Cscopes\5Cclang")
+!2 = !{}
+!7 = !{i32 2, !"CodeView", i32 1}
+!8 = !{i32 2, !"Debug Info Version", i32 3}
+!9 = !{!"clang version 4.0.0 "}
+!10 = distinct !DISubprogram(name: "foo", linkageName: "\01?foo@@YAHXZ", scope: !1, file: !1, line: 1, type: !11, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
+!11 = !DISubroutineType(types: !12)
+!12 = !{!13}
+!13 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
+!14 = !DILocation(line: 2, scope: !10)
-- 
2.35.1.473.g83b2b277ed-goog