Update Clang.cpp

[hw-1]

fix bug with PCH check failed, detail with #76923

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[llvmbot]

@llvm/pr-subscribers-clang-driver

@llvm/pr-subscribers-clang

Author: hw-1 (hw-1)

Changes

fix bug with PCH check failed, detail with #76923

---

Full diff: https://github.com/llvm/llvm-project/pull/77031.diff

1 Files Affected:

• (modified) clang/lib/Driver/ToolChains/Clang.cpp (+1-1)

diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 2d8ef841d4f6be..bb8b496dbfe5fc 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -951,7 +951,7 @@ static void handleAMDGPUCodeObjectVersionOptions(const Driver &D,
 static bool hasClangPchSignature(const Driver &D, StringRef Path) {
   if (llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> MemBuf =
           D.getVFS().getBufferForFile(Path))
-    return (*MemBuf)->getBuffer().starts_with("CPCH");
+    return (*MemBuf)->getBuffer().substr(0x500,-1).starts_with("CPCH");
   return false;
 }
 

[github-actions]

⚠️ C/C++ code formatter, clang-format found issues in your code. ⚠️

You can test this locally with the following command:

git-clang-format --diff c1eef483b2c1ab2564e0ee1e4d1a30db11f8049f 50e69eac786a646491e278478bb096e361d6c4c1 -- clang/lib/Driver/ToolChains/Clang.cpp

View the diff from clang-format here.

diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index bb8b496dbf..0eb32c9b03 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -951,7 +951,7 @@ static void handleAMDGPUCodeObjectVersionOptions(const Driver &D,
 static bool hasClangPchSignature(const Driver &D, StringRef Path) {
   if (llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> MemBuf =
           D.getVFS().getBufferForFile(Path))
-    return (*MemBuf)->getBuffer().substr(0x500,-1).starts_with("CPCH");
+    return (*MemBuf)->getBuffer().substr(0x500, -1).starts_with("CPCH");
   return false;
 }
 

[cor3ntin]

Can you provide a more complete description of your change, a better title?
Does this change needs tests? A release note?

Thanks