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<base href="https://bugs.llvm.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - llvm-exegesis build on x86 doesn't set LLVM_EXEGESIS_INITIALIZE_NATIVE_TARGET"
href="https://bugs.llvm.org/show_bug.cgi?id=39021">39021</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>llvm-exegesis build on x86 doesn't set LLVM_EXEGESIS_INITIALIZE_NATIVE_TARGET
</td>
</tr>
<tr>
<th>Product</th>
<td>Build scripts
</td>
</tr>
<tr>
<th>Version</th>
<td>7.0
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>cmake
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>steven@uplinklabs.net
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Something's up with the llvm-exegesis build process on 7.0.0 release. On my x86
machines they always complain "no exegesis target for x86_64-pc-linux-gnu,
using default", and this seems to be because
LLVM_EXEGESIS_INITIALIZE_NATIVE_TARGET never gets set by CMake.
The CMake scripts try to set LLVM_EXEGESIS_TARGETS in the lib subdirectory, but
this doesn't seem to work properly. I made this change to figure out what's
happening:
---
diff --git a/tools/llvm-exegesis/CMakeLists.txt
b/tools/llvm-exegesis/CMakeLists.txt
index 65b1ada8529..94842519ca7 100644
--- a/tools/llvm-exegesis/CMakeLists.txt
+++ b/tools/llvm-exegesis/CMakeLists.txt
@@ -8,7 +8,9 @@ add_llvm_tool(llvm-exegesis
llvm-exegesis.cpp
)
+message(WARNING "LLVM_EXEGESIS_TARGETS at parent scope before:
${LLVM_EXEGESIS_TARGETS}")
add_subdirectory(lib)
+message(FATAL_ERROR "LLVM_EXEGESIS_TARGETS at parent scope after:
${LLVM_EXEGESIS_TARGETS}")
# Link the native exegesis target if compiled and on the right host.
if ((LLVM_TARGETS_TO_BUILD MATCHES "${LLVM_NATIVE_ARCH}") AND
(LLVM_EXEGESIS_TARGETS MATCHES "${LLVM_NATIVE_ARCH}"))
diff --git a/tools/llvm-exegesis/lib/CMakeLists.txt
b/tools/llvm-exegesis/lib/CMakeLists.txt
index 175c2adf9de..4dc91ef125c 100644
--- a/tools/llvm-exegesis/lib/CMakeLists.txt
+++ b/tools/llvm-exegesis/lib/CMakeLists.txt
@@ -1,12 +1,18 @@
+message( WARNING "LLVM_EXEGESIS_TARGETS before: ${LLVM_EXEGESIS_TARGETS}" )
+
if (LLVM_TARGETS_TO_BUILD MATCHES "X86")
add_subdirectory(X86)
+ message( WARNING "Appending X86" )
set(LLVM_EXEGESIS_TARGETS "${LLVM_EXEGESIS_TARGETS} X86" PARENT_SCOPE)
endif()
if (LLVM_TARGETS_TO_BUILD MATCHES "AArch64")
add_subdirectory(AArch64)
+ message( WARNING "Appending AArch64" )
set(LLVM_EXEGESIS_TARGETS "${LLVM_EXEGESIS_TARGETS} AArch64" PARENT_SCOPE)
endif()
+message( WARNING "LLVM_EXEGESIS_TARGETS after: ${LLVM_EXEGESIS_TARGETS}" )
+
add_library(LLVMExegesis
STATIC
Analysis.cpp
---
This results in this behavior (extraneous newlines removed for readability):
CMake Warning at tools/llvm-exegesis/CMakeLists.txt:11 (message):
LLVM_EXEGESIS_TARGETS at parent scope before:
CMake Warning at tools/llvm-exegesis/lib/CMakeLists.txt:1 (message):
LLVM_EXEGESIS_TARGETS before:
CMake Warning at tools/llvm-exegesis/lib/CMakeLists.txt:5 (message):
Appending X86
CMake Warning at tools/llvm-exegesis/lib/CMakeLists.txt:10 (message):
Appending AArch64
CMake Warning at tools/llvm-exegesis/lib/CMakeLists.txt:14 (message):
LLVM_EXEGESIS_TARGETS after:
CMake Error at tools/llvm-exegesis/CMakeLists.txt:13 (message):
LLVM_EXEGESIS_TARGETS at parent scope after: AArch64
So reading the LLVM_EXEGESIS_TARGETS variable in lib/CMakeLists.txt doesn't
work properly, and the second set(... PARENT_SCOPE) just sees the empty
LLVM_EXEGESIS_TARGETS value, overwriting the previously appended X86 value.
Any ideas on how to fix this? I'm doing this locally but it seems sloppy:
diff --git a/tools/llvm-exegesis/lib/CMakeLists.txt
b/tools/llvm-exegesis/lib/CMakeLists.txt
index 175c2adf9de..194304adf98 100644
--- a/tools/llvm-exegesis/lib/CMakeLists.txt
+++ b/tools/llvm-exegesis/lib/CMakeLists.txt
@@ -1,12 +1,16 @@
+set(TARGETS_TO_APPEND "")
+
if (LLVM_TARGETS_TO_BUILD MATCHES "X86")
add_subdirectory(X86)
- set(LLVM_EXEGESIS_TARGETS "${LLVM_EXEGESIS_TARGETS} X86" PARENT_SCOPE)
+ set(TARGETS_TO_APPEND "${TARGETS_TO_APPEND} X86")
endif()
if (LLVM_TARGETS_TO_BUILD MATCHES "AArch64")
add_subdirectory(AArch64)
- set(LLVM_EXEGESIS_TARGETS "${LLVM_EXEGESIS_TARGETS} AArch64" PARENT_SCOPE)
+ set(TARGETS_TO_APPEND "${TARGETS_TO_APPEND} AArch64")
endif()
+set(LLVM_EXEGESIS_TARGETS "${LLVM_EXEGESIS_TARGETS} ${TARGETS_TO_APPEND}"
PARENT_SCOPE)
+
add_library(LLVMExegesis
STATIC
Analysis.cpp</pre>
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