Saint's Log – Page 3

2024-04-14 —Categories: Manufacturing, Microfabrication, Semiconductors

Semiconductor Manufacturing – Part 2

The post on Processors & Microfabrication was a brief but helpful refresher on the current state of the art in microfabrication. I have found some (more current) interesting videos on chipmaking this past week. After reviewing an introduction to manufacturing, I found myself wondering which area of manufacturing would be interesting to me (one of the chapters had a question like that). It hit me that fabs are the only manufacturing industry that seem really intriguing at this point (perhaps based on my background in computer science). Therefore, I have been trying to get up to speed with what’s happening in semiconductor manufacturing.

The first video on chipmaking in TX gave me a good sense of how many companies are in this space. Learning that the integrated circuit was invented at Texas Instruments leaves me surprised at how little I know about the history of chips. Some of the companies manufacturing chips in TX are Samsung, Texas Instruments, Infineon, Global Wafers, NXP, and Applied Materials. TI mentions their Power management solutions as part of the vast reach of their products. The video highlights the importance of space, power, and water.

How Texas Became The American Chipmaking Hub

Micron is the focus of the following video. It has a fascinating history, having been founded in the basement of a dental office in Boise, ID. Something that stands out to me in the document showing 2.1 million common shares when Micron went public in 1984 is the now infamous Lehman Brothers. It’s interesting seeing the distribution of market share across memory manufacters: Samsung, SK hynix, and Micron sharing about 94% of market share. The rest is split into slivers taken by Winbond, PSMC (powerchip.com), CXMT, and others. I haven’t paid much attention to the memory industry, so HBM3E | Micron Technology Inc. is new to me. I was also surprised to learn that the cost of power is lower in the US than in Asia. How cool is it that Micron also runs a chip camp?

Micron HBM3E 8-high 24GB will ship in NVIDIA H200 Tensor Core GPUs starting in the second calendar quarter 2024.
HBM3E | Micron Technology Inc.

The next video is yet another overview of semiconductor manufacturing. One of the key takeaways for me is that Taiwan leads not just in logic (CPUs, GPUs, etc) but also in memory, courtesy of Micron! 25% of Micron employees are in Taiwan, producing 65% of Micron’s DRAM!

Inside Micron Taiwan’s Semiconductor Factory | Taiwan’s Mega Factories Ep.1

This next video is a survey of the intense competition in the semiconductor industry given its significance in the modern economy. It covers topics like how and why the chips act was passed. See FACT SHEET: One Year after the CHIPS and Science Act, Biden-Harris Administration Marks Historic Progress in Bringing Semiconductor Supply Chains Home, Supporting Innovation, and Protecting National Security | The White House for the PR side of it from the white house. One of the speakers is the author of Chip War: The Fight for the World’s Most Critical Technology: Miller, Chris: 9781982172008: Amazon.com: Books. Sounds like good reading for this summer.

The race for semiconductor supremacy | FT Film

2024-04-13 —Categories: Manufacturing

Introduction to Manufacturing – Part 2

The High-Performance Manufacturing book has a section highlighting a few manufacturing companies. The first is Intel’s Fab 22 in Chandler AZ. Although that highlight is 20 years old, Intel is still active in Chandler. In Intel breaks ground on two new semiconductor factories | City of Chandler (chandleraz.gov), we learn that there will be 6 fabs at the Ocotillo campus.

Featured next is Harley Davidson. I have never really paid attention to these bikes or how they are made so this was quite interesting (especially the in-house road tests)!

How It’s Made: Harley Davidson

Another company highlighted is Union Carbide, which I had never heard of before. It features a production technician at a plant making Butanol in St. Charles LA. This area definitely fell into the unknown unknowns for me.

The History of Union Carbide in Kanawha County, WV

The course links to this video about some biofuel research focused on butanol. Doesn’t seem particularly interesting to me but to each their own.

Last company is American Licorice Company plant in Alsip, IL. The Our Story page mentions that they’re now in Indiana. Yet another product whose origins I never before stopped to ponder.

There is also a link to Mike Rowe’s talk on learning from dirty jobs. I’m only now realizing how big of an advocate of vocational jobs Mike is but then again, I didn’t really watch much of his show so it’s not surprising I’m late to the party.

Learning from dirty jobs | Mike Rowe

Finally, there is a discussion about safety practices and personal protective equipment (PPE).

Personal Protective Equipment (PPE): An Overview of the Basics | Your ACSA Safety Training

I wasn’t sure what to expect from such a course, but it has certainly been educational given that I now see Doritos and my first thought is how was this made and packaged and what does the supply chain look like?

2024-03-30 —Categories: Build Tools and Procedures, Mathematics

Building GMP on Windows (MSYS)

I was recently trying to build the Prime95 Mersenne search software in Visual Studio 2022 when I got error messages about missing a gmp.h dependency.

1>C:\repos\gimps\p95v3019b13.source\common.h(23,10): error C1083: Cannot open include file: 'gmp.h': No such file or directory
...

This got me started trying to figure out how to build the GMP sources on Windows. It was easy to do in the MSYS MINGW64 shell. Use these steps:

cd /c/repos/gmp
curl -Lo gmp-6.3.0.tar.xz https://gmplib.org/download/gmp/gmp-6.3.0.tar.xz
unxz --keep gmp-6.3.0.tar.xz
tar xf gmp-6.3.0.tar
cd gmp-6.3.0
./configure
make

Background Investigation

Searching gmp.h not found windows – Google Search leads to makefile – How to install GMP Mp on windows? (C++) – Stack Overflow. Turns out I need the GNU MP Bignum Library (gmplib.org). The GMP developers’ corner (gmplib.org) points to the repo. It is a mercurial repo! Haven’t seen that in some time!

hg clone https://gmplib.org/repo/gmp/
hg clone https://gmplib.org/repo/gmp-6.3/

Such distractions aside, there is a link to download gmp-6.3.0.tar.xz:

cd /c/repos/gmp

curl -Lo gmp-6.3.0.tar.xz https://gmplib.org/download/gmp/gmp-6.3.0.tar.xz

file gmp-6.3.0.tar.xz

The file command outputs gmp-6.3.0.tar.xz: XZ compressed data, checksum CRC64. Thisrepresents XZ data compression, which is unfamiliar to me (haven’t run into this often). The unxz command can be used to decompress the file with the --keep option to avoid removing the source file.

unxz --keep gmp-6.3.0.tar.xz
tar xf gmp-6.3.0.tar

# Search for gmp.h
cd gmp-6.3.0
find . -name "gmp.h"

Ironically, xz is currently (as I write this post) making the rounds for having recently shipped a back door (All about the xz-utils backdoor | Kali Linux Blog) but I digress. There is no gmp.h file in the new gmp-6.3.0 directory though. The GNU MP Manual (gmplib.org) has a section with Notes for Particular Systems (GNU MP 6.3.0) (gmplib.org).

On an MS-DOS system DJGPP can be used to build GMP, and on an MS Windows system Cygwin, DJGPP and MINGW can be used. All three are excellent ports of GCC and the various GNU tools.
Notes for Particular Systems (GNU MP 6.3.0) (gmplib.org)

Let’s try in Cygwin. Looks like we just run configure then make.

cd /cygdrive/c/repos/gmp/gmp-6.3.0
./configure

Here is the final output from configure.

configure: summary of build options:

  Version:           GNU MP 6.3.0
  Host type:         x86_64-pc-cygwin
  ABI:               64
  Install prefix:    /usr/local
  Compiler:          gcc
  Static libraries:  yes
  Shared libraries:  no

The make command fails though:

Making all in mpn
make[2]: Entering directory '/cygdrive/c/repos/gmp/gmp-6.3.0/mpn'
/bin/sh ../libtool  --tag=CC   --mode=compile gcc -DHAVE_CONFIG_H -I. -I..  -D__GMP_WITHIN_GMP -I.. -DOPERATION_`echo fib_table | sed 's/_$//'`   -O2 -pedantic -fomit-frame-pointer -m64 -mtune=k8 -march=k8 -c -o fib_table.lo fib_table.c
libtool: compile:  gcc -DHAVE_CONFIG_H -I. -I.. -D__GMP_WITHIN_GMP -I.. -DOPERATION_fib_table -O2 -pedantic -fomit-frame-pointer -m64 -mtune=k8 -march=k8 -c fib_table.c -o fib_table.o
In file included from fib_table.c:4:
../gmp-impl.h:146:10: fatal error: ../gmp-mparam.h: Invalid argument
 #include "gmp-mparam.h"
          ^~~~~~~~~~~~~~
compilation terminated.
make[2]: *** [Makefile:492: fib_table.lo] Error 1
make[2]: Leaving directory '/cygdrive/c/repos/gmp/gmp-6.3.0/mpn'
make[1]: *** [Makefile:998: all-recursive] Error 1
make[1]: Leaving directory '/cygdrive/c/repos/gmp/gmp-6.3.0'
make: *** [Makefile:788: all] Error 2

This file exists in the repo! repo/gmp-6.3: 71011d1c130f mpn/x86_64/gmp-mparam.h (gmplib.org). It is linked to on disk.

saint@machine /cygdrive/c/repos/gmp/gmp-6.3.0
$ ls -l  gmp-mparam.h
lrwxrwxrwx 1 saint saint 26 Mar 26 17:14 gmp-mparam.h -> mpn/x86_64/k8/gmp-mparam.h

Search for “fatal error: ../gmp-mparam.h: Invalid argument“. Notice gmp.h in the ls output in this thread: I have a GMP problem. If this is the wrong forum I am sorry to post it here. (gmplib.org).

Trying building it in the MSYS MINGW64 Shell. The end of the ./configure output is shown below. The host type and install prefix are different from the Cygwin environment’s.

config.status: linking mpn/x86_64/k8/gmp-mparam.h to gmp-mparam.h
config.status: executing libtool commands
configure: summary of build options:

  Version:           GNU MP 6.3.0
  Host type:         x86_64-w64-mingw32
  ABI:               64
  Install prefix:    /mingw64
  Compiler:          gcc
  Static libraries:  yes
  Shared libraries:  no

The make command succeeds in the MSYS MINGW64 Shell, running for 4 minutes. I can ignore Cygwin for now. Let’s try the Tutorial on GMP (colorado.edu). Copy the example into a file called mpz_simple1.c then use the command from the tutorial to compile it. Interestingly, I don’t need the -I and -L arguments from the tutorial. The gmp library must already be installed.

cd /c/repos/scratchpad/apps/gmp/tutorial
gcc -o mpz_simple1 mpz_simple1.c -lgmp

To see how gmp.h and the libraries are found, run these commands:

saint@machine MINGW64 /mingw64
$ find . -name "*gmp*"
./bin/libgmp-10.dll
./bin/libgmpxx-4.dll
./include/gmp.h
./include/gmpxx.h
./include/isl/val_gmp.h
./lib/libgmp.a
./lib/libgmp.dll.a
./lib/libgmpxx.a
./lib/libgmpxx.dll.a
./lib/libigmpagnt.a
./lib/pkgconfig/gmp.pc
./lib/pkgconfig/gmpxx.pc
./share/info/gmp.info-1.gz
./share/info/gmp.info-2.gz
./share/info/gmp.info.gz

$ cygpath -w /mingw64
C:\dev\software\msys64\mingw64

Poking around in file explorer shows 2022-01-05 timestamps for gmp.h and libgmp.*. Looks like these were indeed installed with MSYS. How do I automatically output the timestamps for each result of find? bash – How to loop through file names returned by find? – Stack Overflow suggests this command:

find . -name "*gmp*" | while IFS= read -r file; do ls -l $file; done

How do I check the loaded modules to see what is running when I execute this command? windbg – List loaded modules using gdb – Stack Overflow reminds me that process explorer can do this on Windows.

At this point, all we have seen is how to build GMP in the MSYS MINGW64 shell. We have also verified that we can build a sample GMP program, the Tutorial on GMP (colorado.edu). The Cygwin and Visual Studio environments can be investigated another time.

2024-03-30 —Categories: Manufacturing

Introduction to Manufacturing

I have been trying to branch out of computer science/software and learn more about how things are made in the “real world”. Here are some videos that I have watched as part of an online intro to manufacturing course I’m slowly working through. The key idea in the first video is that not everybody needs to get a 4-year degree. Don’t overlook manufacturing when picking a career path.

Path To Careers – The Truth About Manufacturing Careers

The Path to Careers video above features people from these companies:

The next video starts out at Gateway Technical College | Serving Southeastern Wisconsin (gtc.edu).

Made in Wisconsin: A manufacturing special

The video highlights these companies:

The “future of manufacturing” video below might be a bit dated now. I’m not sure how many of its predictions hold as of today.

The Future of Manufacturing

There is also a discussion of the services industry in manufacturing, which is great because it really opens my eyes to how I’ve never really thought much about this sector.

The Evolution of Manufacturing Services Industry

Another video to stimulate some thinking about supply chains:

What Toilet Paper Can Teach Us About Supply Chains | Willy Shih | TEDxBeaconStreet

And why not have some fun with just in time manufacturing?

Just in time manufacturing TBBT

And finally a short tour of a Tesla factory.

Tesla Factory Tour with Elon Musk!

2024-02-02 —Categories: Benchmarks, Java

Running the JMH Benchmark

To build and run the JMH benchmark, ensure Maven is installed (the mvn command should be available in the shell). On Ubuntu, this is as easy as running sudo apt install maven then setting up JMH using the steps below.

git clone https://github.com/swesonga/benchmarks
cd benchmarks
cd java/jmh
./setup_jmh_jdk_micros.sh
./run_jmh_jdk_micros.sh Parallel 1 2 10 5 5

The setup_jmh_jdk_micros.sh script builds the JMH JDK microbenchmarks and the run_jmh_jdk_micros.sh run the benchmark. Someone recently asked why there are 2 java processes shown in top when the run_jmh_jdk_micros.sh script runs given that it launches only 1 java process. I learned from this site how to use top to see java processes only: run top, type ‘o’, then type ‘COMMAND=java’ and press ENTER. This is the resulting output from the top command:

top - 22:15:21 up  8:15,  1 user,  load average: 1.73, 0.66, 0.30
Tasks: 330 total,   1 running, 329 sleeping,   0 stopped,   0 zombie
%Cpu(s): 20.9 us,  0.6 sy,  0.0 ni, 78.3 id,  0.0 wa,  0.0 hi,  0.2 si,  0.0 st
MiB Mem :  15415.5 total,   5837.9 free,   5436.0 used,   4141.6 buff/cache
MiB Swap:   2048.0 total,   2048.0 free,      0.0 used.   9568.6 avail Mem 

    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND                                                                                          
  22007 saint     20   0 5009436   1.1g  22464 S 345.3   7.2   1:02.74 java                                                                                             
  21927 saint     20   0 5607592   1.1g  23100 S   0.3   7.2   0:01.08 java

Sure enough, there are 2 java processes, each with 1.1g RES. This can also be confirmed by running the ps -aux | grep java command.

saint      21927  0.2  7.2 5607592 1141808 pts/2 Sl+  22:15   0:01 /home/saint/java/binaries/jdk/x64/jdk-21.0.1+12/bin/java -Xms1G -Xmx1G -XX:+AlwaysPreTouch -XX:+UseLargePages -jar jmh-jdk-microbenchmarks/micros-uber/target/micros-uberpackage-1.0-SNAPSHOT.jar -f 1 -si true -w 10 -i 5 -wi 5 -t 2 -o ./applogs/Parallel-1G-2024-02-02_22-15-03.txt -rff ./applogs/Parallel-1G-2024-02-02_22-15-03_machine.txt -rf text (?i)\.*(atomic|lock|volatile|ConcurrentHashMap|ProducerConsumer|Queues|ThreadLocalRandomNextInt)\.*
saint      22237  200  7.1 4876316 1125396 pts/2 Sl+  22:21   2:16 /home/saint/java/binaries/jdk/x64/jdk-21.0.1+12/bin/java -Xms1G -Xmx1G -XX:+AlwaysPreTouch -XX:+UseLargePages -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -DcompilerBlackholesEnabled=true -XX:CompileCommandFile=/tmp/jmh12734456823702200189compilecommand -cp jmh-jdk-microbenchmarks/micros-uber/target/micros-uberpackage-1.0-SNAPSHOT.jar org.openjdk.jmh.runner.ForkedMain 127.0.0.1 36835

Notice that one of the processes has an IP address and what is most likely a port number. Without knowing anything else, this would suggest a client/server model in use. To better understand why there are 2 java processes, let us see look at how the run script launches Java. It passes flags like -f 1 to the benchmark jar file. What parses these flags?

The benchmark JAR file is created from a pom.xml file containing a mainClass attribute of org.openjdk.jmh.Main. That’s the class responsible for parsing these flags. This Main class uses the CommandLineOptions class to parse arguments like -f 1 then executes the Runner.run() method. Runner.runBenchmarks() checks whether the benchmarks should be run embedded or forked. runBenchmarksEmbedded() has a warning about using non-forked runs only for debugging purposes. This answers the question of why there are 2 JVMs: we are running in forked mode. runSeparate() has a getForkedMainCommand() method, which suggests that there is most likely a way to pass custom arguments to the ForkedMain JVM.

Now that we understand why there are 2 JVMs, can we control the heap size of each of them independently? The CommandLineOptions class has a list of all the supported arguments. Notice the jvmArgs, jvmArgsAppend, and jvmArgsAppend arguments! These suggest that we can indeed control the heap sizes of each of the JVMs. Use the jvmArgsAppend flag in the run_jmh_jdk_micros.sh script (e.g. just before the benchmark_filter_regex to specify a custom heap size for the forked java process (independent of the jvm_heap_size_opts).

Installing Maven

I did not have Java set up on my Ubuntu VM. Therefore, setting up MVN installed Java and many other dependencies. I decided to list these here for future reference.

saint@vm1ubuntu:~/java$ sudo apt install maven
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following additional packages will be installed:
  ca-certificates-java default-jre-headless java-common libaopalliance-java libapache-pom-java libatinject-jsr330-api-java libcdi-api-java libcommons-cli-java
  libcommons-io-java libcommons-lang3-java libcommons-parent-java libgeronimo-annotation-1.3-spec-java libgeronimo-interceptor-3.0-spec-java libguava-java
  libguice-java libhawtjni-runtime-java libjansi-java libjansi-native-java libjsr305-java libmaven-parent-java libmaven-resolver-java libmaven-shared-utils-java
  libmaven3-core-java libplexus-cipher-java libplexus-classworlds-java libplexus-component-annotations-java libplexus-interpolation-java libplexus-sec-dispatcher-java
  libplexus-utils2-java libsisu-inject-java libsisu-plexus-java libslf4j-java libwagon-file-java libwagon-http-shaded-java libwagon-provider-api-java
  openjdk-11-jre-headless
Suggested packages:
  default-jre libaopalliance-java-doc libatinject-jsr330-api-java-doc libel-api-java libcommons-io-java-doc libcommons-lang3-java-doc libasm-java libcglib-java
  libjsr305-java-doc libmaven-shared-utils-java-doc liblogback-java libplexus-classworlds-java-doc libplexus-sec-dispatcher-java-doc libplexus-utils2-java-doc junit4
  testng libcommons-logging-java liblog4j1.2-java fonts-dejavu-extra fonts-ipafont-gothic fonts-ipafont-mincho fonts-wqy-microhei | fonts-wqy-zenhei
The following NEW packages will be installed:
  ca-certificates-java default-jre-headless java-common libaopalliance-java libapache-pom-java libatinject-jsr330-api-java libcdi-api-java libcommons-cli-java
  libcommons-io-java libcommons-lang3-java libcommons-parent-java libgeronimo-annotation-1.3-spec-java libgeronimo-interceptor-3.0-spec-java libguava-java
  libguice-java libhawtjni-runtime-java libjansi-java libjansi-native-java libjsr305-java libmaven-parent-java libmaven-resolver-java libmaven-shared-utils-java
  libmaven3-core-java libplexus-cipher-java libplexus-classworlds-java libplexus-component-annotations-java libplexus-interpolation-java libplexus-sec-dispatcher-java
  libplexus-utils2-java libsisu-inject-java libsisu-plexus-java libslf4j-java libwagon-file-java libwagon-http-shaded-java libwagon-provider-api-java maven
  openjdk-11-jre-headless
0 upgraded, 37 newly installed, 0 to remove and 72 not upgraded.
Need to get 52.7 MB of archives.
After this operation, 189 MB of additional disk space will be used.
Do you want to continue? [Y/n]

2023-12-29 —Categories: Compilers, LLVM, Visual C++

Trying to Build LLVM for Windows using the Release Script

The post on Tracking Down Missing Headers in LLVM for Windows identified which headers were missing from the LLVM for Windows builds. Let us fix this. Clone the LLVM repo and install the prerequisites as explained at Getting Started with the LLVM System using Microsoft Visual Studio — LLVM 18.0.0git documentation.

7-Zip
Visual Studio 2022

The build_llvm_release.bat script in the LLVM repo is used to create a release build for Windows. Running it without any arguments displays a sample command line to use to build LLVM.

cd \repos && mkdir llvm
cd \repos\llvm\llvm-project\llvm\utils\release

C:\> cd \repos\llvm\llvm-project\llvm\utils\release
C:\repos\llvm\llvm-project\llvm\utils\release> build_llvm_release.bat
--version option is required
=============================
Script for building the LLVM installer on Windows,
used for the releases at https://github.com/llvm/llvm-project/releases

Usage: build_llvm_release.bat --version <version> [--x86,--x64, --arm64]

Options:
--version: [required] version to build
--help: display this help
--x86: build and test x86 variant
--x64: build and test x64 variant
--arm64: build and test arm64 variant

Note: At least one variant to build is required.

Example: build_llvm_release.bat --version 15.0.0 --x86 --x64

Let us build version 17.0.1, which is the latest LLVM release. Open an administrator Developer Command Prompt then run:

:: set PATH=%PATH%;C:\Program Files\7-Zip
build_llvm_release.bat --version 17.0.1 --x64

The first error is caused by mv not being a standard command in the Windows command prompt. There are ways to create aliases, e.g. alias – Aliases in Windows command prompt – Stack Overflow but given that this is a batch file, why not just use the built-in function? I fix this in the script.

C:\repos\llvm\llvm-project\llvm\utils\release\llvm_package_17.0.1> mv llvm-project-* llvm-project   || exit /b 1
'mv' is not recognized as an internal or external command,
operable program or batch file.

The build directory needs to be deleted before restarting the build with the fix. Otherwise, the script will fail.

rmdir /s /q llvm_package_17.0.1

Installing Python

The next things that fails on my machine is setting the python environment. I should have started with Getting Started with the LLVM System using Microsoft Visual Studio — LLVM 18.0.0git documentation. I head to Welcome to Python.org and download Python 3.11.5. The installer says I already have it:

This command confirms that it is installed.

C:\repos\llvm\llvm-project\llvm\utils\release> \Python311\python.exe --version
Python 3.11.0

However, from a new command window, it looks like it hasn’t been set up.

C:\repos> python --version
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.

Just running python loads the Microsoft Store:

I proceed with the Customize Installation option in the open Python installer, this time selecting “for all users (requires admin privileges)”.

I’m not sure why the “Install Python 3.11 for all users” option is not checked on the “Advanced Options” page.

Setup completes successfully. The What’s New In Python 3.11 — Python 3.11.5 documentation page is interesting.

Opening a new command prompt then running python still gives the same behavior as before. where python shows that the new installation appears 2nd.

C:\repos> where python
C:\Users\saint\AppData\Local\Microsoft\WindowsApps\python.exe
C:\Python311\python.exe

The PATH environment variable has these paths in reverse order so I don’t understand what is happening. Looks like the easiest way forward is to just install python from the Microsoft Store – this at least ensures that python scripts can run. After a failure due to the python command not being found, closer inspection of build_llvm_release.bat reveals that it needs the PYTHON_HOME environment variable to be set. However, that is set on line 358 using the python_dir variable, which is in turn the first argument to :set_environment. The call to set_environment is from :do_build_32 (or do_build_64), which uses a hard-coded python path! The script should first validate the python installation and exit early if it cannot be found! I should have reported/fixed these when I worked on Tracking Down Missing Headers in LLVM for Windows – Saint’s Log (swesonga.org) last year.

Build Errors

With the Python path fixed, the build proceeds but the C++ compilation fails. A few months ago I got the error below build version 15.0.7. Unfortunately, I didn’t explicitly note the compiler version.

[5834/6907] Building CXX object tools\lldb\source\Plugins\InstrumentationRuntime\MainThreadChecker\CMakeFiles\lldbPluginInstrumentationRuntimeMainThreadChecker.dir\InstrumentationRuntimeMainThreadChecker.cpp.obj
FAILED: tools/lldb/source/Plugins/InstrumentationRuntime/MainThreadChecker/CMakeFiles/lldbPluginInstrumentationRuntimeMainThreadChecker.dir/InstrumentationRuntimeMainThreadChecker.cpp.obj
C:\PROGRA~1\MICROS~3\2022\COMMUN~1\VC\Tools\MSVC\1437~1.328\bin\Hostx64\x64\cl.exe 
 /nologo
 /TP
 -DGTEST_HAS_RTTI=0
 -DUNICODE
 -D_CRT_NONSTDC_NO_DEPRECATE
 -D_CRT_NONSTDC_NO_WARNINGS
 -D_CRT_SECURE_NO_DEPRECATE
 -D_CRT_SECURE_NO_WARNINGS
 -D_ENABLE_EXTENDED_ALIGNED_STORAGE
 -D_HAS_EXCEPTIONS=0
 -D_SCL_SECURE_NO_DEPRECATE
 -D_SCL_SECURE_NO_WARNINGS
 -D_UNICODE
 -D__STDC_CONSTANT_MACROS
 -D__STDC_FORMAT_MACROS
 -D__STDC_LIMIT_MACROS
 -IC:\repos\llvm\llvm-project\llvm\utils\release\llvm_package_15.0.7\build64_stage0\tools\lldb\source\Plugins\InstrumentationRuntime\MainThreadChecker
 -IC:\repos\llvm\llvm-project\llvm\utils\release\llvm_package_15.0.7\llvm-project\lldb\source\Plugins\InstrumentationRuntime\MainThreadChecker
 -IC:\repos\llvm\llvm-project\llvm\utils\release\llvm_package_15.0.7\llvm-project\lldb\include
 -IC:\repos\llvm\llvm-project\llvm\utils\release\llvm_package_15.0.7\build64_stage0\tools\lldb\include
 -IC:\repos\llvm\llvm-project\llvm\utils\release\llvm_package_15.0.7\build64_stage0\include
 -IC:\repos\llvm\llvm-project\llvm\utils\release\llvm_package_15.0.7\llvm-project\llvm\include
 -IC:\repos\llvm\llvm-project\llvm\utils\release\llvm_package_15.0.7\llvm-project\llvm\..\clang\include
 -IC:\repos\llvm\llvm-project\llvm\utils\release\llvm_package_15.0.7\build64_stage0\tools\lldb\..\clang\include
 -IC:\repos\llvm\llvm-project\llvm\utils\release\llvm_package_15.0.7\llvm-project\lldb\source
 -IC:\repos\llvm\llvm-project\llvm\utils\release\llvm_package_15.0.7\build64_stage0\tools\lldb\source
 -DLIBXML_STATIC
 /Zc:inline
 /Zc:__cplusplus
 /Oi
 /bigobj
 /permissive-
 /W4
 -wd4141
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 -std:c++14
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 /Fotools\lldb\source\Plugins\InstrumentationRuntime\MainThreadChecker\CMakeFiles\lldbPluginInstrumentationRuntimeMainThreadChecker.dir\InstrumentationRuntimeMainThreadChecker.cpp.obj
 /Fdtools\lldb\source\Plugins\InstrumentationRuntime\MainThreadChecker\CMakeFiles\lldbPluginInstrumentationRuntimeMainThreadChecker.dir\lldbPluginInstrumentationRuntimeMainThreadChecker.pdb
 /FS
 -c C:\repos\llvm\llvm-project\llvm\utils\release\llvm_package_15.0.7\llvm-project\lldb\source\Plugins\InstrumentationRuntime\MainThreadChecker\InstrumentationRuntimeMainThreadChecker.cpp
C:\repos\llvm\llvm-project\llvm\utils\release\llvm_package_15.0.7\llvm-project\lldb\source\Plugins\InstrumentationRuntime\MainThreadChecker\InstrumentationRuntimeMainThreadChecker.cpp : fatal error C1083: Cannot open compiler generated file: '': Invalid argument

Today, I got a similar error in InstrumentationRuntimeMainThreadChecker.cpp AND and this internal compiler error using Microsoft (R) C/C++ Optimizing Compiler Version 19.38.33133 for x64!

FAILED: tools/clang/lib/Analysis/FlowSensitive/CMakeFiles/obj.clangAnalysisFlowSensitive.dir/HTMLLogger.cpp.obj
C:\PROGRA~1\MICROS~3\2022\COMMUN~1\VC\Tools\MSVC\1438~1.331\bin\Hostx64\x64\cl.exe  /nologo /TP ... -c C:\repos\llvm\llvm-project\llvm\utils\release\llvm_package_17.0.1\llvm-project\clang\lib\Analysis\FlowSensitive\HTMLLogger.cpp
C:\repos\llvm\llvm-project\llvm\utils\release\llvm_package_17.0.1\llvm-project\clang\lib\Analysis\FlowSensitive\HTMLLogger.cpp(332): fatal error C1001: Internal compiler error.
(compiler file 'msc1.cpp', line 1587)
 To work around this problem, try simplifying or changing the program near the locations listed above.
If possible please provide a repro here: https://developercommunity.visualstudio.com
Please choose the Technical Support command on the Visual C++
 Help menu, or open the Technical Support help file for more information

Additional troubleshooting is obviously required to make progress here. I might try to create a narrowed down testcase for the internal compiler error or perhaps just report it as is and let the Visual C++ team figure that out.

2023-12-28 —Categories: Compilers, Fortran, LLVM

Building Flang with Visual C++ [2022/10]

Note: I wrote this in October 2022 but never got around to posting it. Doing so now to enable comparisons with the latest sources and compilers.

In Failing to Build Flang with Visual C++, the C++ compiler had bugs that prevented compilation from succeeding. I just tried a new version of the Visual C++ compiler (Microsoft (R) C/C++ Optimizing Compiler Version 19.34.31823.3 for x64). This failed to build the same commit with the following error.

D:\dev\repos\llvm-project\flang\lib\Evaluate\fold-implementation.h(1585): error C2220: the following warning is treated as an error
D:\dev\repos\llvm-project\flang\lib\Evaluate\fold-implementation.h(1585): warning C4189: 'ctx': local variable is initialized but not referenced
...

This line was last modified by [flang][msvc] Fix lambda capture ambiguity. NFC. · llvm/llvm-project@0b671a4 (github.com). Can the entire workaround be removed? Some of it was introduced by [flang][msvc] Rework a MSVC work-around to avoid clang warning · llvm/llvm-project@75a5ec1 (github.com). I get the same warning as error if I rename ctx to context. I undo the MSVC workaround and get this error now:

D:\dev\repos\llvm-project\flang\lib\Evaluate\fold-implementation.h(1578): error C2220: the following warning is treated as an error
D:\dev\repos\llvm-project\flang\lib\Evaluate\fold-implementation.h(1578): warning C4101: 'buffer': unreferenced local variable
...

Moving that variable deeper into the if-statement addresses that issue. I end up having to suppress C4661 again.

D:\dev\repos\llvm-project\flang\include\flang\Evaluate\expression.h(101): error C2220: the following warning is treated as an error
D:\dev\repos\llvm-project\flang\include\flang\Evaluate\expression.h(101): warning C4661: 'std::optional<Fortran::evaluate::DynamicType> Fortran::evaluate::ExpressionBase<Fortran::evaluate::SomeDerived>::GetType(void) const': no suitable definition provided for explicit template instantiation request
...

These are the next failures I run into:

C:\PROGRA~1\MIB055~1\2022\Preview\VC\Tools\MSVC\1434~1.318\bin\Hostx64\x64\cl.exe  /nologo /TP -DFLANG_LITTLE_ENDIAN=1 -DGTEST_HAS_RTTI=0 -DUNICODE -D_CRT_NONSTDC_NO_DEPRECATE -D_CRT_NONSTDC_NO_WARNINGS -D_CRT_SECURE_NO_DEPRECATE -D_CRT_SECURE_NO_WARNINGS -D_HAS_EXCEPTIONS=0 -D_SCL_SECURE_NO_DEPRECATE -D_SCL_SECURE_NO_WARNINGS -D_UNICODE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -ID:\dev\repos\llvm-project\build-nowarn\tools\flang\lib\Semantics -ID:\dev\repos\llvm-project\flang\lib\Semantics -ID:\dev\repos\llvm-project\flang\include -ID:\dev\repos\llvm-project\build-nowarn\tools\flang\include -ID:\dev\repos\llvm-project\build-nowarn\include -ID:\dev\repos\llvm-project\llvm\include -external:ID:\dev\repos\llvm-project\llvm\..\mlir\include -external:ID:\dev\repos\llvm-project\build-nowarn\tools\mlir\include -external:ID:\dev\repos\llvm-project\build-nowarn\tools\clang\include -external:ID:\dev\repos\llvm-project\llvm\..\clang\include -external:W0 /DWIN32 /D_WINDOWS   /Zc:inline /Zc:__cplusplus /Oi /bigobj /permissive- /W4 -wd4141 -wd4146 -wd4244 -wd4267 -wd4291 -wd4351 -wd4456 -wd4457 -wd4458 -wd4459 -wd4503 -wd4624 -wd4722 -wd4100 -wd4127 -wd4512 -wd4505 -wd4610 -wd4510 -wd4702 -wd4245 -wd4706 -wd4310 -wd4701 -wd4703 -wd4389 -wd4611 -wd4805 -wd4204 -wd4577 -wd4091 -wd4592 -wd4319 -wd4709 -wd4661 -wd4324 -w14062 -we4238 /Gw /WX /MD /O2 /Ob2  /EHs-c- /GR- -UNDEBUG -std:c++17 /showIncludes /Fotools\flang\lib\Semantics\CMakeFiles\obj.FortranSemantics.dir\mod-file.cpp.obj /Fdtools\flang\lib\Semantics\CMakeFiles\obj.FortranSemantics.dir\ /FS -c D:\dev\repos\llvm-project\flang\lib\Semantics\mod-file.cpp
D:\dev\repos\llvm-project\flang\lib\Semantics\mod-file.cpp(962): error C2220: the following warning is treated as an error
D:\dev\repos\llvm-project\flang\lib\Semantics\mod-file.cpp(962): warning C4834: discarding return value of function with 'nodiscard' attribute

c++ – What’s the reason for not using C++17’s [[nodiscard]] almost everywhere in new code? – Software Engineering Stack Exchange has a link to the proposal of [[nodiscard]] and other attributes. This is easy to resolve by casting the result to (void) as per Compiler warning (Level 1) C4834 | Microsoft Docs.


[4578/5288] Building CXX object tools\flang\lib\Semantics\CMakeFiles\obj.FortranSemantics.dir\expression.cpp.obj

C:\PROGRA~1\MIB055~1\2022\Preview\VC\Tools\MSVC\1434~1.318\bin\Hostx64\x64\cl.exe  /nologo /TP -DFLANG_LITTLE_ENDIAN=1 -DGTEST_HAS_RTTI=0 -DUNICODE -D_CRT_NONSTDC_NO_DEPRECATE -D_CRT_NONSTDC_NO_WARNINGS -D_CRT_SECURE_NO_DEPRECATE -D_CRT_SECURE_NO_WARNINGS -D_HAS_EXCEPTIONS=0 -D_SCL_SECURE_NO_DEPRECATE -D_SCL_SECURE_NO_WARNINGS -D_UNICODE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -ID:\dev\repos\llvm-project\build-nowarn\tools\flang\lib\Semantics -ID:\dev\repos\llvm-project\flang\lib\Semantics -ID:\dev\repos\llvm-project\flang\include -ID:\dev\repos\llvm-project\build-nowarn\tools\flang\include -ID:\dev\repos\llvm-project\build-nowarn\include -ID:\dev\repos\llvm-project\llvm\include -external:ID:\dev\repos\llvm-project\llvm\..\mlir\include -external:ID:\dev\repos\llvm-project\build-nowarn\tools\mlir\include -external:ID:\dev\repos\llvm-project\build-nowarn\tools\clang\include -external:ID:\dev\repos\llvm-project\llvm\..\clang\include -external:W0 /DWIN32 /D_WINDOWS   /Zc:inline /Zc:__cplusplus /Oi /bigobj /permissive- /W4 -wd4141 -wd4146 -wd4244 -wd4267 -wd4291 -wd4351 -wd4456 -wd4457 -wd4458 -wd4459 -wd4503 -wd4624 -wd4722 -wd4100 -wd4127 -wd4512 -wd4505 -wd4610 -wd4510 -wd4702 -wd4245 -wd4706 -wd4310 -wd4701 -wd4703 -wd4389 -wd4611 -wd4805 -wd4204 -wd4577 -wd4091 -wd4592 -wd4319 -wd4709 -wd4661 -wd4324 -w14062 -we4238 /Gw /WX /MD /O2 /Ob2  /EHs-c- /GR- -UNDEBUG -std:c++17 /showIncludes /Fotools\flang\lib\Semantics\CMakeFiles\obj.FortranSemantics.dir\expression.cpp.obj /Fdtools\flang\lib\Semantics\CMakeFiles\obj.FortranSemantics.dir\ /FS -c D:\dev\repos\llvm-project\flang\lib\Semantics\expression.cpp
D:\dev\repos\llvm-project\flang\lib\Semantics\expression.cpp(1192): error C2220: the following warning is treated as an error
D:\dev\repos\llvm-project\flang\lib\Semantics\expression.cpp(1192): warning C4927: illegal conversion; more than one user-defined conversion has been implicitly applied
D:\dev\repos\llvm-project\flang\lib\Semantics\expression.cpp(1192): note: while calling the constructor 'Fortran::semantics::Symbol::Symbol(const Fortran::semantics::Symbol &) noexcept(false)'
D:\dev\repos\llvm-project\flang\include\flang\Semantics\symbol.h(734): note: compiler has generated 'Fortran::semantics::Symbol::Symbol' here

C:\PROGRA~1\MIB055~1\2022\Preview\VC\Tools\MSVC\1434~1.318\bin\Hostx64\x64\cl.exe  /nologo /TP -DFLANG_LITTLE_ENDIAN=1 -DGTEST_HAS_RTTI=0 -DUNICODE -D_CRT_NONSTDC_NO_DEPRECATE -D_CRT_NONSTDC_NO_WARNINGS -D_CRT_SECURE_NO_DEPRECATE -D_CRT_SECURE_NO_WARNINGS -D_HAS_EXCEPTIONS=0 -D_SCL_SECURE_NO_DEPRECATE -D_SCL_SECURE_NO_WARNINGS -D_UNICODE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -ID:\dev\repos\llvm-project\build-nowarn\tools\flang\lib\Semantics -ID:\dev\repos\llvm-project\flang\lib\Semantics -ID:\dev\repos\llvm-project\flang\include -ID:\dev\repos\llvm-project\build-nowarn\tools\flang\include -ID:\dev\repos\llvm-project\build-nowarn\include -ID:\dev\repos\llvm-project\llvm\include -external:ID:\dev\repos\llvm-project\llvm\..\mlir\include -external:ID:\dev\repos\llvm-project\build-nowarn\tools\mlir\include -external:ID:\dev\repos\llvm-project\build-nowarn\tools\clang\include -external:ID:\dev\repos\llvm-project\llvm\..\clang\include -external:W0 /DWIN32 /D_WINDOWS   /Zc:inline /Zc:__cplusplus /Oi /bigobj /permissive- /W4 -wd4141 -wd4146 -wd4244 -wd4267 -wd4291 -wd4351 -wd4456 -wd4457 -wd4458 -wd4459 -wd4503 -wd4624 -wd4722 -wd4100 -wd4127 -wd4512 -wd4505 -wd4610 -wd4510 -wd4702 -wd4245 -wd4706 -wd4310 -wd4701 -wd4703 -wd4389 -wd4611 -wd4805 -wd4204 -wd4577 -wd4091 -wd4592 -wd4319 -wd4709 -wd4661 -wd4324 -w14062 -we4238 /Gw /WX /MD /O2 /Ob2  /EHs-c- /GR- -UNDEBUG -std:c++17 /showIncludes /Fotools\flang\lib\Semantics\CMakeFiles\obj.FortranSemantics.dir\resolve-names.cpp.obj /Fdtools\flang\lib\Semantics\CMakeFiles\obj.FortranSemantics.dir\ /FS -c D:\dev\repos\llvm-project\flang\lib\Semantics\resolve-names.cpp
D:\dev\repos\llvm-project\flang\lib\Semantics\resolve-names.cpp(3151): error C2220: the following warning is treated as an error
D:\dev\repos\llvm-project\flang\lib\Semantics\resolve-names.cpp(3151): warning C4927: illegal conversion; more than one user-defined conversion has been implicitly applied
D:\dev\repos\llvm-project\flang\lib\Semantics\resolve-names.cpp(3151): note: while calling the constructor 'Fortran::semantics::Symbol::Symbol(const Fortran::semantics::Symbol &) noexcept(false)'
D:\dev\repos\llvm-project\flang\include\flang\Semantics\symbol.h(734): note: compiler has generated 'Fortran::semantics::Symbol::Symbol' here

This same warning appears in more files:

C:\PROGRA~1\MIB055~1\2022\Preview\VC\Tools\MSVC\1434~1.318\bin\Hostx64\x64\cl.exe  /nologo /TP -DFLANG_LITTLE_ENDIAN=1 -DGTEST_HAS_RTTI=0 -DUNICODE -D_CRT_NONSTDC_NO_DEPRECATE -D_CRT_NONSTDC_NO_WARNINGS -D_CRT_SECURE_NO_DEPRECATE -D_CRT_SECURE_NO_WARNINGS -D_HAS_EXCEPTIONS=0 -D_SCL_SECURE_NO_DEPRECATE -D_SCL_SECURE_NO_WARNINGS -D_UNICODE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -ID:\dev\repos\llvm-project\build-nowarn\tools\flang\lib\Semantics -ID:\dev\repos\llvm-project\flang\lib\Semantics -ID:\dev\repos\llvm-project\flang\include -ID:\dev\repos\llvm-project\build-nowarn\tools\flang\include -ID:\dev\repos\llvm-project\build-nowarn\include -ID:\dev\repos\llvm-project\llvm\include -external:ID:\dev\repos\llvm-project\llvm\..\mlir\include -external:ID:\dev\repos\llvm-project\build-nowarn\tools\mlir\include -external:ID:\dev\repos\llvm-project\build-nowarn\tools\clang\include -external:ID:\dev\repos\llvm-project\llvm\..\clang\include -external:W0 /DWIN32 /D_WINDOWS   /Zc:inline /Zc:__cplusplus /Oi /bigobj /permissive- /W4 -wd4141 -wd4146 -wd4244 -wd4267 -wd4291 -wd4351 -wd4456 -wd4457 -wd4458 -wd4459 -wd4503 -wd4624 -wd4722 -wd4100 -wd4127 -wd4512 -wd4505 -wd4610 -wd4510 -wd4702 -wd4245 -wd4706 -wd4310 -wd4701 -wd4703 -wd4389 -wd4611 -wd4805 -wd4204 -wd4577 -wd4091 -wd4592 -wd4319 -wd4709 -wd4661 -wd4324 -w14062 -we4238 /Gw /WX /MD /O2 /Ob2  /EHs-c- /GR- -UNDEBUG -std:c++17 /showIncludes /Fotools\flang\lib\Semantics\CMakeFiles\obj.FortranSemantics.dir\semantics.cpp.obj /Fdtools\flang\lib\Semantics\CMakeFiles\obj.FortranSemantics.dir\ /FS -c D:\dev\repos\llvm-project\flang\lib\Semantics\semantics.cpp
D:\dev\repos\llvm-project\flang\lib\Semantics\semantics.cpp(511): error C2220: the following warning is treated as an error
D:\dev\repos\llvm-project\flang\lib\Semantics\semantics.cpp(511): warning C4927: illegal conversion; more than one user-defined conversion has been implicitly applied
D:\dev\repos\llvm-project\flang\lib\Semantics\semantics.cpp(511): note: while calling the constructor 'Fortran::semantics::Symbol::Symbol(const Fortran::semantics::Symbol &) noexcept(false)'
D:\dev\repos\llvm-project\flang\include\flang\Semantics\symbol.h(734): note: compiler has generated 'Fortran::semantics::Symbol::Symbol' here

This last error is different because it comes from a generated source file.

C:\PROGRA~1\MIB055~1\2022\Preview\VC\Tools\MSVC\1434~1.318\bin\Hostx64\x64\cl.exe  /nologo /TP -DFLANG_LITTLE_ENDIAN=1 -DGTEST_HAS_RTTI=0 -DUNICODE -D_CRT_NONSTDC_NO_DEPRECATE -D_CRT_NONSTDC_NO_WARNINGS -D_CRT_SECURE_NO_DEPRECATE -D_CRT_SECURE_NO_WARNINGS -D_HAS_EXCEPTIONS=0 -D_SCL_SECURE_NO_DEPRECATE -D_SCL_SECURE_NO_WARNINGS -D_UNICODE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -ID:\dev\repos\llvm-project\build-nowarn\tools\flang\lib\Optimizer\Dialect -ID:\dev\repos\llvm-project\flang\lib\Optimizer\Dialect -ID:\dev\repos\llvm-project\flang\include -ID:\dev\repos\llvm-project\build-nowarn\tools\flang\include -ID:\dev\repos\llvm-project\build-nowarn\include -ID:\dev\repos\llvm-project\llvm\include -external:ID:\dev\repos\llvm-project\llvm\..\mlir\include -external:ID:\dev\repos\llvm-project\build-nowarn\tools\mlir\include -external:ID:\dev\repos\llvm-project\build-nowarn\tools\clang\include -external:ID:\dev\repos\llvm-project\llvm\..\clang\include -external:W0 /DWIN32 /D_WINDOWS   /Zc:inline /Zc:__cplusplus /Oi /bigobj /permissive- /W4 -wd4141 -wd4146 -wd4244 -wd4267 -wd4291 -wd4351 -wd4456 -wd4457 -wd4458 -wd4459 -wd4503 -wd4624 -wd4722 -wd4100 -wd4127 -wd4512 -wd4505 -wd4610 -wd4510 -wd4702 -wd4245 -wd4706 -wd4310 -wd4701 -wd4703 -wd4389 -wd4611 -wd4805 -wd4204 -wd4577 -wd4091 -wd4592 -wd4319 -wd4709 -wd4661 -wd4324 -w14062 -we4238 /Gw /WX /MD /O2 /Ob2  /EHs-c- /GR- -UNDEBUG -std:c++17 /showIncludes /Fotools\flang\lib\Optimizer\Dialect\CMakeFiles\obj.FIRDialect.dir\FIROps.cpp.obj /Fdtools\flang\lib\Optimizer\Dialect\CMakeFiles\obj.FIRDialect.dir\ /FS -c D:\dev\repos\llvm-project\flang\lib\Optimizer\Dialect\FIROps.cpp
D:\dev\repos\llvm-project\build-nowarn\tools\flang\include\flang/Optimizer/Dialect/CanonicalizationPatterns.inc(386): error C2220: the following warning is treated as an error
D:\dev\repos\llvm-project\build-nowarn\tools\flang\include\flang/Optimizer/Dialect/CanonicalizationPatterns.inc(386): warning C4927: illegal conversion; more than one user-defined conversion has been implicitly applied

Next error is because resolve-names.cpp has a function that doesn’t return a value in some path. Did this compile before?

C:\PROGRA~1\MIB055~1\2022\Preview\VC\Tools\MSVC\1434~1.318\bin\Hostx64\x64\cl.exe  /nologo /TP -DFLANG_LITTLE_ENDIAN=1 -DGTEST_HAS_RTTI=0 -DUNICODE -D_CRT_NONSTDC_NO_DEPRECATE -D_CRT_NONSTDC_NO_WARNINGS -D_CRT_SECURE_NO_DEPRECATE -D_CRT_SECURE_NO_WARNINGS -D_HAS_EXCEPTIONS=0 -D_SCL_SECURE_NO_DEPRECATE -D_SCL_SECURE_NO_WARNINGS -D_UNICODE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -ID:\dev\repos\llvm-project\build-nowarn\tools\flang\lib\Semantics -ID:\dev\repos\llvm-project\flang\lib\Semantics -ID:\dev\repos\llvm-project\flang\include -ID:\dev\repos\llvm-project\build-nowarn\tools\flang\include -ID:\dev\repos\llvm-project\build-nowarn\include -ID:\dev\repos\llvm-project\llvm\include -external:ID:\dev\repos\llvm-project\llvm\..\mlir\include -external:ID:\dev\repos\llvm-project\build-nowarn\tools\mlir\include -external:ID:\dev\repos\llvm-project\build-nowarn\tools\clang\include -external:ID:\dev\repos\llvm-project\llvm\..\clang\include -external:W0 /DWIN32 /D_WINDOWS   /Zc:inline /Zc:__cplusplus /Oi /bigobj /permissive- /W4 -wd4141 -wd4146 -wd4244 -wd4267 -wd4291 -wd4351 -wd4456 -wd4457 -wd4458 -wd4459 -wd4503 -wd4624 -wd4722 -wd4100 -wd4127 -wd4512 -wd4505 -wd4610 -wd4510 -wd4702 -wd4245 -wd4706 -wd4310 -wd4701 -wd4703 -wd4389 -wd4611 -wd4805 -wd4204 -wd4577 -wd4091 -wd4592 -wd4319 -wd4709 -wd4661 -wd4927 -wd4324 -w14062 -we4238 /Gw /WX /MD /O2 /Ob2  /EHs-c- /GR- -UNDEBUG -std:c++17 /showIncludes /Fotools\flang\lib\Semantics\CMakeFiles\obj.FortranSemantics.dir\resolve-names.cpp.obj /Fdtools\flang\lib\Semantics\CMakeFiles\obj.FortranSemantics.dir\ /FS -c D:\dev\repos\llvm-project\flang\lib\Semantics\resolve-names.cpp
D:\dev\repos\llvm-project\flang\lib\Semantics\resolve-names.cpp(2796) : error C2220: the following warning is treated as an error
D:\dev\repos\llvm-project\flang\lib\Semantics\resolve-names.cpp(2796) : warning C4715: '`Fortran::semantics::ModuleVisitor::DoAddUse'::`2'::<lambda_1>::operator()': not all control paths return a value

Oh boy, them errors keep coming:

C:\PROGRA~1\MIB055~1\2022\Preview\VC\Tools\MSVC\1434~1.318\bin\Hostx64\x64\cl.exe  /nologo /TP -DFLANG_LITTLE_ENDIAN=1 -DUNICODE -D_CRT_NONSTDC_NO_DEPRECATE -D_CRT_NONSTDC_NO_WARNINGS -D_CRT_SECURE_NO_DEPRECATE -D_CRT_SECURE_NO_WARNINGS -D_SCL_SECURE_NO_DEPRECATE -D_SCL_SECURE_NO_WARNINGS -D_UNICODE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -ID:\dev\repos\llvm-project\build-nowarn\tools\flang\unittests\Evaluate -ID:\dev\repos\llvm-project\flang\unittests\Evaluate -ID:\dev\repos\llvm-project\flang\include -ID:\dev\repos\llvm-project\build-nowarn\tools\flang\include -ID:\dev\repos\llvm-project\build-nowarn\include -ID:\dev\repos\llvm-project\llvm\include -external:ID:\dev\repos\llvm-project\llvm\..\mlir\include -external:ID:\dev\repos\llvm-project\build-nowarn\tools\mlir\include -external:ID:\dev\repos\llvm-project\build-nowarn\tools\clang\include -external:ID:\dev\repos\llvm-project\llvm\..\clang\include -external:W0 /DWIN32 /D_WINDOWS   /Zc:inline /Zc:__cplusplus /Oi /bigobj /permissive- /W4 -wd4141 -wd4146 -wd4244 -wd4267 -wd4291 -wd4351 -wd4456 -wd4457 -wd4458 -wd4459 -wd4503 -wd4624 -wd4722 -wd4100 -wd4127 -wd4512 -wd4505 -wd4610 -wd4510 -wd4702 -wd4245 -wd4706 -wd4310 -wd4701 -wd4703 -wd4389 -wd4611 -wd4805 -wd4204 -wd4577 -wd4091 -wd4592 -wd4319 -wd4709 -wd4661 -wd4927 -wd4324 -w14062 -we4238 /Gw /WX /MD /O2 /Ob2 -UNDEBUG -std:c++17 /showIncludes /Fotools\flang\unittests\Evaluate\CMakeFiles\FortranEvaluateTesting.dir\fp-testing.cpp.obj /Fdtools\flang\unittests\Evaluate\CMakeFiles\FortranEvaluateTesting.dir\FortranEvaluateTesting.pdb /FS -c D:\dev\repos\llvm-project\flang\unittests\Evaluate\fp-testing.cpp
C:\Program Files\Microsoft Visual Studio\2022\Preview\VC\Tools\MSVC\14.34.31823\include\xtree(1664): error C2220: the following warning is treated as an error
C:\Program Files\Microsoft Visual Studio\2022\Preview\VC\Tools\MSVC\14.34.31823\include\xtree(1626): note: see reference to function template instantiation 'std::_Tree_node<std::pair<const Fortran::parser::CharBlock,Fortran::common::ConstantSubscript>,std::_Default_allocator_traits<_Alloc>::void_pointer> *std::_Tree<std::_Tmap_traits<_Kty,_Ty,_Pr,_Alloc,false>>::_Copy_nodes<std::_Tree<std::_Tmap_traits<_Kty,_Ty,_Pr,_Alloc,false>>::_Strategy::_Copy>(std::_Tree_node<std::pair<const Fortran::parser::CharBlock,Fortran::common::ConstantSubscript>,std::_Default_allocator_traits<_Alloc>::void_pointer> *,std::_Tree_node<std::pair<const Fortran::parser::CharBlock,Fortran::common::ConstantSubscript>,std::_Default_allocator_traits<_Alloc>::void_pointer> *)' being compiled
        with
        [
            _Alloc=std::allocator<std::pair<const Fortran::parser::CharBlock,Fortran::common::ConstantSubscript>>,
            _Kty=Fortran::parser::CharBlock,
            _Ty=Fortran::common::ConstantSubscript,
            _Pr=std::less<Fortran::parser::CharBlock>
        ]
...
C:\Program Files\Microsoft Visual Studio\2022\Preview\VC\Tools\MSVC\14.34.31823\include\map(109): note: while compiling class template member function 'std::map<Fortran::parser::CharBlock,Fortran::common::ConstantSubscript,std::less<Fortran::parser::CharBlock>,std::allocator<std::pair<const Fortran::parser::CharBlock,Fortran::common::ConstantSubscript>>>::map(const std::map<Fortran::parser::CharBlock,Fortran::common::ConstantSubscript,std::less<Fortran::parser::CharBlock>,std::allocator<std::pair<const Fortran::parser::CharBlock,Fortran::common::ConstantSubscript>>> &)'
D:\dev\repos\llvm-project\flang\include\flang/Evaluate/common.h(243): note: see reference to function template instantiation 'std::map<Fortran::parser::CharBlock,Fortran::common::ConstantSubscript,std::less<Fortran::parser::CharBlock>,std::allocator<std::pair<const Fortran::parser::CharBlock,Fortran::common::ConstantSubscript>>>::map(const std::map<Fortran::parser::CharBlock,Fortran::common::ConstantSubscript,std::less<Fortran::parser::CharBlock>,std::allocator<std::pair<const Fortran::parser::CharBlock,Fortran::common::ConstantSubscript>>> &)' being compiled
D:\dev\repos\llvm-project\flang\include\flang/Evaluate/common.h(291): note: see reference to class template instantiation 'std::map<Fortran::parser::CharBlock,Fortran::common::ConstantSubscript,std::less<Fortran::parser::CharBlock>,std::allocator<std::pair<const Fortran::parser::CharBlock,Fortran::common::ConstantSubscript>>>' being compiled
C:\Program Files\Microsoft Visual Studio\2022\Preview\VC\Tools\MSVC\14.34.31823\include\xtree(1664): warning C4530: C++ exception handler used, but unwind semantics are not enabled. Specify /EHsc

I try setting this flag just at the end of the if(MSVC) block in HandleLLVMOptions.cmake. Unfortunately, the build still fails and that’s when I notice that the earlier command lines in this post have the /EHs-c- flag. Looks like HandleLLVMOptions.cmake is explicitly removing such flags. The next logical step is to search for /EH in the codebase to see how it’s getting set for the commands that have it. That’s when I notice clang-cl – looks like a cl.exe immitation. Maybe this is how they’ve been building flang for windows without addressing all these Visual C++ issues?

https://github.com/llvm/llvm-project/blob/c0702ac07b8e206f424930ff0331151954fb821c/libc/cmake/modules/LLVMLibCObjectRules.cmake#L25

There is talk of using clang-cl on non-Windows hosts to target MSVC in llvm-project/WinMsvc.cmake at 00874c48ea4d291908517afaab50d1dcbfb016c3 · llvm/llvm-project (github.com). Discovered this when investigating the packing issue in the LLVM missing headers post.

Back to the exception handling issue: searching for /EHsc leads me to AddLLVM.cmake which references the LLVM_ENABLE_EH variable. Looks like that defaults to OFF in HandleLLVMOptions.cmake and it also needs LLVM_ENABLE_RTTI to be enabled.

cmake -G Ninja ../llvm -DCMAKE_BUILD_TYPE=Release -DFLANG_ENABLE_WERROR=On -DLLVM_ENABLE_ASSERTIONS=ON -DLLVM_TARGETS_TO_BUILD=host -DCMAKE_INSTALL_PREFIX=../install -DLLVM_LIT_ARGS=-v -DLLVM_ENABLE_PROJECTS="clang;mlir;flang" -DLLVM_ENABLE_RUNTIMES="compiler-rt" -DLLVM_ENABLE_EH=ON -DLLVM_ENABLE_RTTI=ON

The fact that this still doesn’t address the warning is the red flag forcing me to notice that this is a unit test and we probably don’t want to turn on RTTI anyway. That would be a huge change! Let’s drop these flags and instead modify the flang/unittests/CMakeLists.txt to add the -EHsc flag. That turns out to be exactly the right fix! Building with this command line takes about 1hr 55min on my desktop.

mkdir build
cd build
cmake -G Ninja ../llvm -DCMAKE_BUILD_TYPE=Release -DFLANG_ENABLE_WERROR=On -DLLVM_ENABLE_ASSERTIONS=ON -DLLVM_TARGETS_TO_BUILD=host -DCMAKE_INSTALL_PREFIX=../install -DLLVM_LIT_ARGS=-v -DLLVM_ENABLE_PROJECTS="clang;mlir;flang" -DLLVM_ENABLE_RUNTIMES="compiler-rt" && ninja

At this point, the commit I’ve been using and the Visual Studio build (17.4.0 Preview 3 with C++ compiler version 19.34.31823.3) are outdated. Let’s see what happens with the latest code and Visual Studio 17.4.0 Preview 4 (with C++ compiler version 19.34.31931). Bad timing on my part though, the installer now says Preview 5.0 is available and it comes with Microsoft (R) C/C++ Optimizing Compiler Version 19.34.31932 for x86. Not sure why these new preview builds are showing the x86 host when launching the developer command prompt from the start menu. Doesn’t happen when using the drop down in Windows Terminal.

Outstanding Tasks

Expand on std::vector /EHsc – Search (bing.com) and visual c++ – std::vector without exceptions: warning C4530: C++ exception handler used, but unwind semantics are not enabled. Specify /EHsc – Stack Overflow

2023-12-26 —Categories: Chemistry

Discovery of Neutrons & Radiation

One of the questions I had at the end of the Chemistry Basics II post was about how neurons were discovered. I guess these two channels have become my go to sources for these explanations. The Chadwick and the Neutron video presents a bit more history (e.g. the involvement of Marie Curie’s daughter).

chadwick and the neutron

I like the next video because it poses several questions that should be hints that the model without neutrons.

Atomic Structure: Discovery of the Neutron

The use of radiation in these experiments naturally raises the question of how these various types of radiation were discovered. Kathy Loves Physics addresses this in her video.

Alpha Beta Gamma: History of Radioactivity [CC]

2023-12-24 —Categories: Abstract Algebra, Mathematics

Graph Isomorphism

The Graph Isomorphism problem currently has a deterministic quasi-polynomial time algorithm. This time bound is a breakthrough from the previously best known upper bound of exponential time (in the size of the graph). I started looking at Babai’s paper on [1512.03547] Graph Isomorphism in Quasipolynomial Time (arxiv.org). Many of the key concepts involve abstract algebra, e.g. automorphism groups. This video is a great refresher on automorphisms.

Graph Theory FAQs: 02. Graph Automorphisms

I found it helpful to dig a little bit deeper into automorphisms via Visual Group Theory, Lecture 4.6: Automorphisms – YouTube. This video uses Cayley graphs, which I haven’t studied before but is still a good overview of the automorphism groups.

Visual Group Theory, Lecture 4.6: Automorphisms

The “Graph Isomorphism in Quasipolynomial Time” paper is quite involved. I was pleasantly surprised to find a University of Chicago lecture by Babai on this result few months ago. I still came away short of understanding the proof after watching the video.

The foundations of this line of research comes partially from the paper showing that Isomorphism of Graphs of Bounded Valence Can Be Tested in Polynomial Time. I started looking into this paper to try to understand the fundamentals in the simpler case where the degree of the graph is bounded. There are many algebraic concepts that I still need a refresher on to get an intuitive feel for this old paper. However, [2011.01366] Recent Advances on the Graph Isomorphism Problem (arxiv.org) gives a higher level view of what is happening and is therefore my key aide at this point in shedding some light on these graph isomorphism algorithms. It has, for example, pointed me to the color refinement algorithm. Details about this algorithm are available in this Color Refinement and its Applications paper.

2023-12-23 —Categories: Aerospace

Overview of Tilt Rotor Aircraft

We had an aviation and computers club in high school. The student that led the club was very knowledgeable about all sorts of aircraft and their capabilities. I have recently been learning more about the V-22 Osprey and thought I might as well save links to the more informative videos I’ve watched. It is this exercise that reminded me of that high school club. There are many videos on the V-22 out there. The video below provides a good introduction to the V-22, perhaps the most recognizable tilt rotor aircraft out there.

The V-22 Osprey: US Most Advanced Hybrid Aircraft Ever Built

One of the things I particularly liked about the video below was that it showed engineers working on aircraft models (e.g. propellers) in SolidWorks. Here’s a screenshot of a SolidWorks model at about 14:42 into the video above.

Another interesting video on the V-22 is this one from Business Insider. I like that it presents a bit more about the operational aspects of how the marines use the V-22.

Unfortunately, there have been many fatal accidents involving the V-22 Osprey. Ward Carroll discusses this troubled history and how the program made it through to today, at which point the V-22s have been grounded.

The first video mentioned NASA designing a rotor aircraft and this is worth searching for: nasa rotor aircraft – Google Search. One result that stands out to me is NASA’s PDF on the History of the XV-15 Tilt Rotor Research Aircraft from Concept to Flight. It would be interesting to read a more recent survey of the field. For example, Bell has also created the V-280 Valor, a clean sheet design based on lessons from the V-22. The US Military Defence YouTube channel has a good overview of this tilt rotor aircraft in the next video.

V-280 Is Coming: Get Ready for the Next-Generation Aircraft

The last tidbit on the V-22 is from this video, Why is the V-22 Osprey only sold to Japan – YouTube. It points out that the V-22 uses the AE 1107C engine.