[clang] c511963 - [clang] Fix length threshold for MicrosoftMangle md5 hash

[Melanie Blower via cfe-commits]

Author: Melanie Blower
Date: 2020-11-07T07:40:24-08:00
New Revision: c511963d5adb1a8ca16adabf4b49f8d013a66785

URL: https://github.com/llvm/llvm-project/commit/c511963d5adb1a8ca16adabf4b49f8d013a66785
DIFF: https://github.com/llvm/llvm-project/commit/c511963d5adb1a8ca16adabf4b49f8d013a66785.diff

LOG: [clang] Fix length threshold for MicrosoftMangle md5 hash

Reviewers: rnk, dblaikie

Differential Revision: https://reviews.llvm.org/D90714

Added: 
    

Modified: 
    clang/lib/AST/MicrosoftMangle.cpp
    clang/test/CodeGenCXX/mangle-ms-md5.cpp

Removed: 
    


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diff  --git a/clang/lib/AST/MicrosoftMangle.cpp b/clang/lib/AST/MicrosoftMangle.cpp
index 3a263d487b75..de03a88d7612 100644
--- a/clang/lib/AST/MicrosoftMangle.cpp
+++ b/clang/lib/AST/MicrosoftMangle.cpp
@@ -50,7 +50,7 @@ struct msvc_hashing_ostream : public llvm::raw_svector_ostream {
     bool StartsWithEscape = MangledName.startswith("\01");
     if (StartsWithEscape)
       MangledName = MangledName.drop_front(1);
-    if (MangledName.size() <= 4096) {
+    if (MangledName.size() < 4096) {
       OS << str();
       return;
     }

diff  --git a/clang/test/CodeGenCXX/mangle-ms-md5.cpp b/clang/test/CodeGenCXX/mangle-ms-md5.cpp
index 52a29324af05..bd7cef2f099b 100644
--- a/clang/test/CodeGenCXX/mangle-ms-md5.cpp
+++ b/clang/test/CodeGenCXX/mangle-ms-md5.cpp
@@ -49,3 +49,25 @@ void g() {
 // HAVECTOR: "_CT??@c14087f0ec22b387aea7c59083f4f546@??@4ef4f8979c81f9d2224b32bf327e6bdf at 4"
 }
 #endif
+
+// Verify the threshold where md5 mangling kicks in
+// Test an ident with 4088 characters, pre-hash, MangleName.size() is 4095
+#define X4088(X)                                \
+    C2(C2(                                      \
+      C4(X,       X4(X),   X4(X),    X8(X)),    \
+      C4(X8(X),   X32(X),  X64(X),   X128(X))), \
+      C4(X256(X), X512(X), X1024(X), X2048(X)))
+#define Z4088 X4088(z)
+// Use initialization to verify mangled name association in the il
+int X4088(z) = 1515;
+// CHECK-DAG: @"?{{z+}}@@3HA" = dso_local global i32 1515, align 4
+
+// Test an ident with 4089 characters, pre-hash, MangleName.size() is 4096
+#define X4089(X)                                \
+    C2(C2(                                      \
+      C4(X2(X),   X4(X),   X4(X),    X8(X)),    \
+      C4(X8(X),   X32(X),  X64(X),   X128(X))), \
+      C4(X256(X), X512(X), X1024(X), X2048(X)))
+// Use initialization to verify mangled name association in the il
+int X4089(z) = 1717;
+// CHECK-DAG: @"??@0269945400a3474730d6880df0967d8f@" = dso_local global i32 1717, align 4