Add support for configurable hashing for source checksums

[KevinRansom]

Internal thread:

From: Mike Lai
Sent: Monday, May 23, 2016 3:44 PM
To: Kevin Ransom Kevin.Ransom@microsoft.com
Cc: Michael Fanning (DEVDIV) Michael.Fanning@microsoft.com; Tomas Matousek Tomas.Matousek@microsoft.com
Subject: RE: F# Compiler (fsc.exe)

I see, Kevin. Would you mind to consider our request to make SHA256 as one of available sections, please?

All the following compilers support SHA256 today.

Thanks
Mike

• cl.exe /ZH:SHA_256
• ml.exe /ZH:SHA_256
• ml64.exe /ZH:SHA_256
• armasm.exe -gh:SHA_256
• armasm64.exe -gh:SHA_256
• csc.exe /checksumalgorithm:SHA256

From: Kevin Ransom
Sent: Monday, May 23, 2016 3:40 PM
To: Mike Lai mikelai@microsoft.com
Cc: Michael Fanning (DEVDIV) Michael.Fanning@microsoft.com; Tomas Matousek Tomas.Matousek@microsoft.com
Subject: Re: F# Compiler (fsc.exe)

Not selectable and MD5

https://github.com/Microsoft/visualfsharp/blob/master/src/absil/ilwritepdb.fs#L126

Kevin
From: Mike Lai mikelai@microsoft.com
Date: Monday, May 23, 2016 at 3:30 PM
To: Kevin Ransom Kevin.Ransom@microsoft.com
Cc: "Michael Fanning (DEVDIV)" Michael.Fanning@microsoft.com, Tomas Matousek Tomas.Matousek@microsoft.com
Subject: RE: F# Compiler (fsc.exe)

Hi Kevin -- It is about the hashes of compiled source files being written by the compiler to the pdb files?

What kind (SHA1 or SHA256) of hashes does the F# Compiler (fsc.exe) put in the pdb files ?

CSC.exe can put either based on the “/checksumalgorithm:” switch. I am wondering if fsc.exe can support the same please?

Thanks

Mike

From: Kevin Ransom
Sent: Monday, May 23, 2016 3:26 PM
To: Mike Lai mikelai@microsoft.com
Cc: Michael Fanning (DEVDIV) Michael.Fanning@microsoft.com; Tomas Matousek Tomas.Matousek@microsoft.com
Subject: Re: F# Compiler (fsc.exe)

Hey Mike,

Can you let me know what this is about?

Thanks

Kevin

From: Mike Lai mikelai@microsoft.com
Date: Monday, May 23, 2016 at 2:10 PM
To: Kevin Ransom Kevin.Ransom@microsoft.com
Cc: "Michael Fanning (DEVDIV)" Michael.Fanning@microsoft.com, Tomas Matousek Tomas.Matousek@microsoft.com
Subject: RE: F# Compiler (fsc.exe)

Thanks Tomas for the introduction! Hi Kevin – please find enclosed the background information on why we are driving this. Please feel free to let me know if you have additional questions.

Thanks
Mike

From: Tomas Matousek
Sent: Monday, May 23, 2016 1:56 PM
To: Kevin Ransom Kevin.Ransom@microsoft.com
Cc: Michael Fanning (DEVDIV) Michael.Fanning@microsoft.com; Mike Lai mikelai@microsoft.com
Subject: RE: F# Compiler (fsc.exe)

Kevin, F# needs “/checksumalgorithm:” command line switch to set the algorithm to calculate document hash saved to PDB.
Mike is driving the effort to get the option to all compilers.

Thanks,
Tomas

[tmat]

This switch determines the algorithm used to calculate source file checksums stored in PDB.

The corresponding MSBuild task property is ChecksumAlgorithm.

Supported values should include SHA1 and SHA256. See Roslyn for details:

http://source.roslyn.io/#Microsoft.CodeAnalysis.CSharp/CommandLine/CSharpCommandLineParser.cs,286

The default in Roslyn is currently SHA1. We are considering switching to SHA256:

dotnet/roslyn#24820

[tmat]

@KevinRansom Can we do this work for 15.7?

[KevinRansom]

@tmat I will add it to my list

[tmat]

The default in Roslyn is currently SHA1. We are considering switching to SHA256.

We did switch Roslyn to SHA256. F# should also default to SHA256.