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cranelift: improve debug value locations around cold blocks#12484

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cfallin merged 1 commit intobytecodealliance:mainfrom
philipc:issue-11337
Feb 4, 2026
Merged

cranelift: improve debug value locations around cold blocks#12484
cfallin merged 1 commit intobytecodealliance:mainfrom
philipc:issue-11337

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@philipc philipc commented Feb 1, 2026

If a debug range started or ended on an instruction from a cold block, we omitted the entire range. Fix by skipping the instructions in the cold block to find the next valid offset.

Closes #11337

@philipc philipc requested review from a team as code owners February 1, 2026 06:02
@philipc philipc requested review from cfallin and dicej and removed request for a team February 1, 2026 06:02
@philipc
cranelift: improve debug value locations around cold blocks
cf70053 
If a debug range started or ended on an instruction from a cold block,
we omitted the entire range. Fix by skipping the instructions in the
cold block to find the next valid offset.
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philipc commented Feb 1, 2026

Before this change, the WASMTIME_LOG=cranelift_codegen::machinst::vcode=trace output for foo showed:

|BB|Inst    |IP         |VL0     |VL1      |VL2     |VL3      |VL4     |VL5     |VL6     |VL7     |VL8     |VL9     |VL10    |VL11    |VL12    |VL13    |VL14    |VL15    |VL16    |VL17    |VL18    |VL4294967294|
|--|--------|-----------|--------|---------|--------|---------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|------------|
|B0|Inst 0  |53         |    |   |    |    |    |   |    |    |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |       |
|  |Inst 1  |53         |v194|p2i|    |    |    |   |    |    |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |v192|p7i    |
|  |Inst 2  |60         |*   |p2i|v269|p13i|v196|   |    |    |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |*   |p7i    |
|  |Inst 3  |64         |*   |p2i|*   |p13i|*   |   |v268|p14i|    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |*   |p7i    |
|  |Inst 4  |68         |*   |p2i|*   |p13i|*   |   |*   |p14i|    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |*   |p7i    |
|  |Inst 5  |72         |*   |p2i|*   |p13i|*   |   |*   |p14i|    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |*   |p7i    |
|  |Inst 6  |76         |*   |p2i|*   |p13i|*   |   |*   |p14i|    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |*   |p7i    |
|  |Inst 7  |81         |*   |p2i|*   |p13i|*   |   |*   |p14i|    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |*   |p7i    |
|  |Inst 8  |83         |*   |   |*   |p13i|*   |   |*   |p14i|v265|p0i|    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |*   |p7i    |
|  |Inst 9  |88         |*   |   |*   |p13i|*   |   |*   |p14i|*   |   |v264|p1i|    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |*   |p7i    |
|  |Inst 10 |88         |*   |   |*   |p13i|*   |   |*   |p14i|*   |   |*   |p1i|    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |*   |p7i    |
|  |Inst 11 |91         |*   |   |*   |p13i|*   |   |*   |p14i|*   |   |*   |p1i|    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |*   |p7i    |
|  |Inst 12 |98         |*   |   |*   |p13i|*   |   |*   |p14i|*   |   |*   |p1i|    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |*   |p9i    |
|  |Inst 13 |100        |*   |   |*   |p13i|*   |   |*   |p14i|*   |   |*   |p1i|    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |*   |p9i    |
|  |Inst 14 |104        |*   |   |*   |p13i|*   |   |*   |p14i|*   |   |*   |p1i|    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |*   |p9i    |
|  |Inst 15 |107        |*   |   |*   |p13i|*   |   |*   |p14i|*   |   |*   |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |*   |p9i    |
|  |Inst 16 |111        |*   |   |*   |p13i|*   |   |*   |p14i|*   |   |*   |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |*   |p9i    |
|  |Inst 17 |117        |*   |   |*   |p13i|*   |   |*   |p14i|*   |   |*   |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |*   |p9i    |
|  |Inst 18 |121        |*   |   |*   |p13i|*   |   |*   |p14i|*   |   |*   |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |*   |p9i    |
|  |Inst 19 |124        |*   |   |*   |p13i|*   |   |*   |p14i|*   |   |*   |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |*   |p9i    |
|B1|Inst 20 |133        |*   |   |*   |p13i|*   |   |*   |p14i|*   |   |*   |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |*   |p9i    |
|B2|Inst 21 |4294967295 |*   |   |*   |p13i|*   |   |*   |p14i|*   |   |*   |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |*   |p9i    |
|  |Inst 22 |4294967295 |*   |   |*   |p13i|*   |   |*   |p14i|*   |   |*   |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |*   |p9i    |
|  |Inst 23 |4294967295 |*   |   |v255|p6i |v255|p6i|v255|p6i |v255|p6i|v255|p6i|v255|p6i|v255|p6i|v255|p6i|v255|p6i|v255|p6i|v255|p6i|v255|p6i|v255|p6i|v255|p6i|v255|p6i|v255|p6i|v255|p6i|v255|p6i|*   |p12i   |
|  |Inst 24 |4294967295 |*   |   |*   |    |*   |   |*   |    |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |p12i   |
|B3|Inst 25 |133        |*   |   |*   |    |*   |   |*   |    |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |p12i   |
|  |Inst 26 |137        |*   |   |*   |    |*   |   |*   |    |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |p12i   |
|  |Inst 27 |142        |*   |   |*   |    |*   |   |*   |    |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |p12i   |
|  |Inst 28 |145        |*   |   |*   |    |*   |   |*   |    |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |p12i   |
|  |Inst 29 |151        |*   |   |*   |    |*   |   |*   |    |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |p12i   |
|  |Inst 30 |155        |*   |   |*   |    |*   |   |*   |    |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |p12i   |
|  |Inst 31 |162        |*   |   |*   |    |*   |   |*   |    |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |p12i   |
|  |Inst 32 |164        |*   |   |*   |    |*   |   |*   |    |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |p12i   |
|  |Inst 33 |167        |*   |   |*   |    |*   |   |*   |    |*   |   |*   |   |v248|p7i|*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |p12i   |
|  |Inst 34 |171        |*   |   |*   |    |*   |   |*   |    |*   |   |*   |   |*   |   |v247|p7i|v234|   |v247|p7i|v234|   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |p12i   |
|  |Inst 35 |174        |*   |   |*   |    |*   |   |*   |    |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |p12i   |
|B4|Inst 36 |180        |*   |   |*   |    |*   |   |*   |    |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |p12i   |
|  |Inst 37 |189        |*   |   |*   |    |*   |   |*   |    |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |p12i   |
|B5|Inst 38 |194        |*   |   |*   |    |*   |   |*   |    |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |v240|   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |p12i   |
|  |Inst 39 |203        |*   |   |*   |    |*   |   |*   |    |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |p12i   |
|B6|Inst 40 |203        |*   |   |*   |    |*   |   |*   |    |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |p12i   |
|  |Inst 41 |208        |*   |   |*   |    |*   |   |*   |    |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |v246|p0i|*   |   |*   |   |*   |p12i   |
|  |Inst 42 |213        |*   |   |*   |    |*   |   |*   |    |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |p0i|*   |   |*   |   |*   |p12i   |
|  |Inst 43 |213        |*   |   |*   |    |*   |   |*   |    |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |   |*   |p0i|*   |   |*   |   |*   |       |
Recording debug range for VL0 in Reg(p2i): [Inst 1..Inst 8) [53..83)
Recording debug range for VL3 in Reg(p14i): [Inst 3..Inst 5) [64..72)
Recording debug range for VL4 in Reg(p0i): [Inst 8..Inst 9) [83..88)
Recording debug range for VL5 in Reg(p1i): [Inst 9..Inst 15) [88..107)
Recording debug range for VL6 in Reg(p7i): [Inst 33..Inst 34) [167..171)
Recording debug range for VL7 in Reg(p7i): [Inst 34..Inst 35) [171..174)
Recording debug range for VL9 in Reg(p7i): [Inst 34..Inst 35) [171..174)
Recording debug range for VL16 in Reg(p0i): [Inst 41..Inst 44) [208..264)
Recording debug range for VL4294967294 in Reg(p7i): [Inst 1..Inst 12) [53..98)

After this change we get:

Recording debug range for VL0 in Reg(p2i): [Inst 1..Inst 8) [53..83)
Recording debug range for VL1 in Reg(p13i): [Inst 2..Inst 23) [60..133)
Recording debug range for VL3 in Reg(p14i): [Inst 3..Inst 5) [64..72)
Extending debug range for VL3 in Reg(p14i) to Inst 23 (133)
Recording debug range for VL4 in Reg(p0i): [Inst 8..Inst 9) [83..88)
Recording debug range for VL5 in Reg(p1i): [Inst 9..Inst 15) [88..107)
Recording debug range for VL6 in Reg(p7i): [Inst 33..Inst 34) [167..171)
Recording debug range for VL7 in Reg(p7i): [Inst 34..Inst 35) [171..174)
Recording debug range for VL9 in Reg(p7i): [Inst 34..Inst 35) [171..174)
Recording debug range for VL16 in Reg(p0i): [Inst 41..Inst 44) [208..264)
Recording debug range for VL4294967294 in Reg(p7i): [Inst 1..Inst 12) [53..98)
Recording debug range for VL4294967294 in Reg(p9i): [Inst 12..Inst 23) [98..133)
Recording debug range for VL4294967294 in Reg(p12i): [Inst 23..Inst 43) [133..213)

@philipc philipc mentioned this pull request Feb 1, 2026
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@github-actions github-actions bot added cranelift Issues related to the Cranelift code generator cranelift:area:machinst Issues related to instruction selection and the new MachInst backend. labels Feb 1, 2026
cfallin
cfallin approved these changes Feb 4, 2026
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Thanks!

@cfallin cfallin added this pull request to the merge queue Feb 4, 2026
Merged via the queue into bytecodealliance:main with commit 9fe4cc1 Feb 4, 2026
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@philipc philipc deleted the issue-11337 branch February 4, 2026 21:59
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@cfallin cfallin cfallin approved these changes

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"Couldn't materialize" error in debugger after indirect call

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