[clang] d8c6d24 - -funique-internal-linkage-names appends a hex md5hash suffix to the symbol name which is not demangler friendly, convert it to decimal.

[Sriraman Tallam via cfe-commits]

Author: Sriraman Tallam
Date: 2021-01-11T11:10:29-08:00
New Revision: d8c6d24359f17c55a8966231ef74e8f4b03ad282

URL: https://github.com/llvm/llvm-project/commit/d8c6d24359f17c55a8966231ef74e8f4b03ad282
DIFF: https://github.com/llvm/llvm-project/commit/d8c6d24359f17c55a8966231ef74e8f4b03ad282.diff

LOG: -funique-internal-linkage-names appends a hex md5hash suffix to the symbol name which is not demangler friendly, convert it to decimal.

Please see D93747 for more context which tries to make linkage names of internal
linkage functions to be the uniqueified names. This causes a problem with gdb
because breaking using the demangled function name will not work if the new
uniqueified name cannot be demangled. The problem is the generated suffix which
is a mix of integers and letters which do not demangle. The demangler accepts
either all numbers or all letters. This patch simply converts the hash to decimal.

There is no loss of uniqueness by doing this as the precision is maintained.
The symbol names get longer by a few characters though.

Differential Revision: https://reviews.llvm.org/D94154

Added: 
    

Modified: 
    clang/test/CodeGen/unique-internal-linkage-names.cpp
    llvm/lib/Transforms/Utils/UniqueInternalLinkageNames.cpp
    llvm/test/Transforms/UniqueInternalLinkageNames/unique_symbol_names.ll

Removed: 
    


################################################################################
diff  --git a/clang/test/CodeGen/unique-internal-linkage-names.cpp b/clang/test/CodeGen/unique-internal-linkage-names.cpp
index 3ad3bdc9f1bbb..b731ed07f4a76 100644
--- a/clang/test/CodeGen/unique-internal-linkage-names.cpp
+++ b/clang/test/CodeGen/unique-internal-linkage-names.cpp
@@ -53,15 +53,15 @@ int mver_call() {
 // PLAIN: define weak_odr i32 ()* @_ZL4mverv.resolver()
 // PLAIN: define internal i32 @_ZL4mverv()
 // PLAIN: define internal i32 @_ZL4mverv.sse4.2()
-// UNIQUE: @_ZL4glob.__uniq.{{[0-9a-f]+}} = internal global
-// UNIQUE: @_ZZ8retAnonMvE5fGlob.__uniq.{{[0-9a-f]+}} = internal global
-// UNIQUE: @_ZN12_GLOBAL__N_16anon_mE.__uniq.{{[0-9a-f]+}} = internal global
-// UNIQUE: define internal i32 @_ZL3foov.__uniq.{{[0-9a-f]+}}()
-// UNIQUE: define internal i32 @_ZN12_GLOBAL__N_14getMEv.__uniq.{{[0-9a-f]+}}
+// UNIQUE: @_ZL4glob.__uniq.{{[0-9]+}} = internal global
+// UNIQUE: @_ZZ8retAnonMvE5fGlob.__uniq.{{[0-9]+}} = internal global
+// UNIQUE: @_ZN12_GLOBAL__N_16anon_mE.__uniq.{{[0-9]+}} = internal global
+// UNIQUE: define internal i32 @_ZL3foov.__uniq.{{[0-9]+}}()
+// UNIQUE: define internal i32 @_ZN12_GLOBAL__N_14getMEv.__uniq.{{[0-9]+}}
 // UNIQUE: define weak_odr i32 ()* @_ZL4mverv.resolver()
-// UNIQUE: define internal i32 @_ZL4mverv.__uniq.{{[0-9a-f]+}}()
-// UNIQUE: define internal i32 @_ZL4mverv.sse4.2.__uniq.{{[0-9a-f]+}}
-// UNIQUEO1: define internal i32 @_ZL3foov.__uniq.{{[0-9a-f]+}}()
+// UNIQUE: define internal i32 @_ZL4mverv.__uniq.{{[0-9]+}}()
+// UNIQUE: define internal i32 @_ZL4mverv.sse4.2.__uniq.{{[0-9]+}}
+// UNIQUEO1: define internal i32 @_ZL3foov.__uniq.{{[0-9]+}}()
 // UNIQUEO1: define weak_odr i32 ()* @_ZL4mverv.resolver()
-// UNIQUEO1: define internal i32 @_ZL4mverv.__uniq.{{[0-9a-f]+}}()
-// UNIQUEO1: define internal i32 @_ZL4mverv.sse4.2.__uniq.{{[0-9a-f]+}}
+// UNIQUEO1: define internal i32 @_ZL4mverv.__uniq.{{[0-9]+}}()
+// UNIQUEO1: define internal i32 @_ZL4mverv.sse4.2.__uniq.{{[0-9]+}}

diff  --git a/llvm/lib/Transforms/Utils/UniqueInternalLinkageNames.cpp b/llvm/lib/Transforms/Utils/UniqueInternalLinkageNames.cpp
index 385bf8bb429ae..29ad0b6fcae50 100644
--- a/llvm/lib/Transforms/Utils/UniqueInternalLinkageNames.cpp
+++ b/llvm/lib/Transforms/Utils/UniqueInternalLinkageNames.cpp
@@ -27,9 +27,12 @@ static bool uniqueifyInternalLinkageNames(Module &M) {
   Md5.final(R);
   SmallString<32> Str;
   llvm::MD5::stringifyResult(R, Str);
+  // Convert MD5hash to Decimal. Demangler suffixes can either contain numbers
+  // or characters but not both.
+  APInt IntHash = APInt(128, Str.str(), 16);
   // Prepend "__uniq" before the hash for tools like profilers to understand that
   // this symbol is of internal linkage type.
-  std::string ModuleNameHash = (Twine(".__uniq.") + Twine(Str)).str();
+  std::string ModuleNameHash = (Twine(".__uniq.") + Twine(IntHash.toString(10, false))).str();
   bool Changed = false;
 
   // Append the module hash to all internal linkage functions.

diff  --git a/llvm/test/Transforms/UniqueInternalLinkageNames/unique_symbol_names.ll b/llvm/test/Transforms/UniqueInternalLinkageNames/unique_symbol_names.ll
index bf15daebda383..492c716a0bb11 100644
--- a/llvm/test/Transforms/UniqueInternalLinkageNames/unique_symbol_names.ll
+++ b/llvm/test/Transforms/UniqueInternalLinkageNames/unique_symbol_names.ll
@@ -10,5 +10,5 @@ entry:
   ret i32 0
 }
 
-; CHECK: @glob.__uniq.6ae72bb15a7d1834b42ae042a58f7a4d = internal global
-; CHECK: define internal i32 @foo.__uniq.6ae72bb15a7d1834b42ae042a58f7a4d()
+; CHECK: @glob.__uniq.142098474322525230676991677820000238157 = internal global
+; CHECK: define internal i32 @foo.__uniq.142098474322525230676991677820000238157()