Fix CFG on our static-lib-only DLL projects #16056
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(cherry picked from commit 447841463bfda0f5dc4476bfe0ae324e1f5c54b1)
zadjii-msft
approved these changes
Sep 29, 2023
| @@ -101,6 +101,13 @@ | |||
| <PreferredToolArchitecture>x64</PreferredToolArchitecture> | |||
| <EnableHybridCRT Condition="'$(EnableHybridCRT)'=='' and '$(ConfigurationSupportsHybridCRT)'=='true'">true</EnableHybridCRT> | |||
| <UseCrtSDKReferenceStaticWarning Condition="'$(EnableHybridCRT)'=='true'">false</UseCrtSDKReferenceStaticWarning> | |||
| <!-- | |||
| We must set this to True for projects that do not contain any ClCompile entries. | |||
| The Link task guesses whether to enable CFG based on ClCompile->ControlFlowGuard. | |||
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Does it use the metadata of items in the Sources parameter for that? From the Link task documentation, I'd have expected the ObjectFiles parameter instead, but that one has type String[] and thus cannot carry any metadata.
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Yep, it uses the ClCompile item metadata
Microsoft\VC\v170\Microsoft.CppCommon.targets
1091: <LinkControlFlowGuard Condition="'$(LinkControlFlowGuard)' == '' and '@(ClCompile)' != '' and '@(ClCompile->AnyHaveMetadataValue('ControlFlowGuard', 'Guard'))' == 'true'">true</LinkControlFlowGuard>
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Oh that's not the Link task doing the guessing then.
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You're right of course, and you caught me out on describing it improperly :)
lhecker
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Sep 29, 2023
DHowett
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Sep 29, 2023
Control Flow Guard requires both linker and compiler flags. It turns out that the MSVC build rules determine whether to _link_ with CFG based on whether it compiled anything with CFG. It also turns out that when you don't compile anything (such as in our DLL projects that only consume a static library!), the build rules can't guess whether to link with CFG. Whoops. We need to force it. (cherry picked from commit 1b143e3) Service-Card-Id: 90688104 Service-Version: 1.18
DHowett
added a commit
that referenced
this pull request
Sep 29, 2023
Control Flow Guard requires both linker and compiler flags. It turns out that the MSVC build rules determine whether to _link_ with CFG based on whether it compiled anything with CFG. It also turns out that when you don't compile anything (such as in our DLL projects that only consume a static library!), the build rules can't guess whether to link with CFG. Whoops. We need to force it. (cherry picked from commit 1b143e3) Service-Card-Id: 90688105 Service-Version: 1.19
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Control Flow Guard requires both linker and compiler flags.
It turns out that the MSVC build rules determine whether to link with CFG based on whether it compiled anything with CFG.
It also turns out that when you don't compile anything (such as in our DLL projects that only consume a static library!), the build rules can't guess whether to link with CFG.
Whoops.
We need to force it.